Self-control of traffic lights and vehicle flows in urban road networks

NASA Astrophysics Data System (ADS)

Lämmer, Stefan; Helbing, Dirk

2008-04-01

Based on fluid-dynamic and many-particle (car-following) simulations of traffic flows in (urban) networks, we study the problem of coordinating incompatible traffic flows at intersections. Inspired by the observation of self-organized oscillations of pedestrian flows at bottlenecks, we propose a self-organization approach to traffic light control. The problem can be treated as a multi-agent problem with interactions between vehicles and traffic lights. Specifically, our approach assumes a priority-based control of traffic lights by the vehicle flows themselves, taking into account short-sighted anticipation of vehicle flows and platoons. The considered local interactions lead to emergent coordination patterns such as 'green waves' and achieve an efficient, decentralized traffic light control. While the proposed self-control adapts flexibly to local flow conditions and often leads to non-cyclical switching patterns with changing service sequences of different traffic flows, an almost periodic service may evolve under certain conditions and suggests the existence of a spontaneous synchronization of traffic lights despite the varying delays due to variable vehicle queues and travel times. The self-organized traffic light control is based on an optimization and a stabilization rule, each of which performs poorly at high utilizations of the road network, while their proper combination reaches a superior performance. The result is a considerable reduction not only in the average travel times, but also of their variation. Similar control approaches could be applied to the coordination of logistic and production processes.

Current state of traffic pollution in Bangladesh and metropolitan Dhaka

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karim, Masud; Matsui, Hiroshi; Ohno, Takashi

1997-12-31

Limited resources, invested for the development of transport facilities, such as infrastructure and vehicles, coupled with the rapid rise in transport demand, existence of a huge number of non-motorized vehicles on roads, lack of application of adequate and proper traffic management schemes are producing severe transport problems in almost all the urban areas of Bangladesh. Worsening situation of traffic congestion in the streets and sufferings of the inhabitants from vehicle emissions demand extensive research in this field. However, no detailed study concerning traffic congestion and pollution problems for urban areas of Bangladesh has yet been done. Therefore, it has becomemore » increasingly important to examine the present state of the problem. This research is a preliminary evaluation of the current situation of traffic pollution problem in Bangladesh. The daily total emissions of NO{sub x}, HC, CO, PM, and SO{sub x} are estimated using the daily fuel consumption and total traffic flows in Dhaka city. Estimated daily emissions are 42, 39, 314, 14, and 42 t/d for NO{sub x}, HC, CO, PM, and SO{sub x}, respectively. The emissions estimated using two different methods revealed good correlation. Daily average concentration of NO{sub x} (NO{sub 2}, NO) were measured at 30 street locations in Dhaka city during September and November, 1996. The results showed extremely high concentrations of NO{sub 2} and NO in these locations.« less

Improving pedestrian facilities in congested urban areas: a case study of Chennai city

NASA Astrophysics Data System (ADS)

Subramanyam, B.; Prasanna Kumar, R.

2017-07-01

Traffic congestion and lack of public pedestrian space are some problems faced by most urban metropolises. Conventionally walking has been a mode of transportation in Indian cities. The percentage of pedestrians may vary from 16 to 57 depending upon the city. Encounters between vehicular traffic and pedestrian traffic are at its rise currently. Rapid industrialization and urbanization in India has resulted in neglecting of pedestrian facilities. Consequently pedestrian are at greater risk for their safety more especially in the commercial zones of large cities. A change in perspective spotlight will create a sense of awareness that the pedestrian traffic is also vital as the vehicular traffic. Soothing the traffic would moderately cut the driving expediency but the pedestrians will get a much safer and peaceful route to their terminuses. Safety and comfort are the two pans of a balance while considering the pedestrian traffic. Considering these aspects, this study deals a study in improving pedestrian facilities by analysing the existing skeleton of the selected locations. The adequacy of facility is checked based on IRC latest guidelines and counteractive measures are postulated.

a Cross-Sectional Study on Insomnia among Japanese Adult Women in Relation to Night-Time Road Traffic Noise

NASA Astrophysics Data System (ADS)

Kageyama, T.; Kabuto, M.; Nitta, N.; Kurokawa, Y.; Taira, K.; Suzuki, S.; Takemoto, T.

1997-08-01

In an effort to determine the contribution of night-time road traffic noise to insomnia in the general population, 3600 adult Japanese women living in urban residential areas were surveyed. Living near a road with a heavy traffic volume is one of the risk factors for insomnia. The risk for insomnia in the zones 0-20 m from the main roads increased linearly with the night-time traffic volume. This suggests that road traffic noise raises the sound level in bedrooms in such zones, and consequently the prevalence rate of insomnia among the residents, and that noise-induced insomnia is an important public health problem, at least in highly urbanized areas.

Strategy research of harbin city green transport and sustainable development from low carbon ecological perspective

NASA Astrophysics Data System (ADS)

Qiang, Wang; Xiao-jie, Qi

2017-04-01

With quick development of urbanization and mechanization, there exist some problems in the cities, such as traffic jam, traffic safety, and traffic pollution and so on. It is extremely urgent for the city to develop green transport, in order to relieve these problems and push forward low carbon ecological construction in Harbin. Strategy research of Harbin city green transport and sustainable development is done from the eight aspects of building public transport system of integration, bicycle, walking, and slow-moving system and so on based on analyzing demands of low carbon ecology on city green transport development, and Harbin traffic development state.

Towards Realistic Urban Traffic Experiments Using DFROUTER: Heuristic, Validation and Extensions.

PubMed

Zambrano-Martinez, Jorge Luis; Calafate, Carlos T; Soler, David; Cano, Juan-Carlos

2017-12-15

Traffic congestion is an important problem faced by Intelligent Transportation Systems (ITS), requiring models that allow predicting the impact of different solutions on urban traffic flow. Such an approach typically requires the use of simulations, which should be as realistic as possible. However, achieving high degrees of realism can be complex when the actual traffic patterns, defined through an Origin/Destination (O-D) matrix for the vehicles in a city, remain unknown. Thus, the main contribution of this paper is a heuristic for improving traffic congestion modeling. In particular, we propose a procedure that, starting from real induction loop measurements made available by traffic authorities, iteratively refines the output of DFROUTER, which is a module provided by the SUMO (Simulation of Urban MObility) tool. This way, it is able to generate an O-D matrix for traffic that resembles the real traffic distribution and that can be directly imported by SUMO. We apply our technique to the city of Valencia, and we then compare the obtained results against other existing traffic mobility data for the cities of Cologne (Germany) and Bologna (Italy), thereby validating our approach. We also use our technique to determine what degree of congestion is expectable if certain conditions cause additional traffic to circulate in the city, adopting both a uniform pattern and a hotspot-based pattern for traffic injection to demonstrate how to regulate the overall number of vehicles in the city. This study allows evaluating the impact of vehicle flow changes on the overall traffic congestion levels.

Development of a prototype vehicle-infrastructure integration system for real-time traffic management.

DOT National Transportation Integrated Search

2008-08-01

Freeway congestion is a major problem in many urban areas. It has been estimated that freeway incidents (events that impede the flow of traffic: accidents, disabled vehicles, etc.) account for one-half to three-fourths of the total congestion on metr...

Top-down quantification of NOx emissions from traffic in an urban area using a high-resolution regional atmospheric chemistry model

NASA Astrophysics Data System (ADS)

Kuik, Friderike; Kerschbaumer, Andreas; Lauer, Axel; Lupascu, Aurelia; von Schneidemesser, Erika; Butler, Tim M.

2018-06-01

With NO2 limit values being frequently exceeded in European cities, complying with the European air quality regulations still poses a problem for many cities. Traffic is typically a major source of NOx emissions in urban areas. High-resolution chemistry transport modelling can help to assess the impact of high urban NOx emissions on air quality inside and outside of urban areas. However, many modelling studies report an underestimation of modelled NOx and NO2 compared with observations. Part of this model bias has been attributed to an underestimation of NOx emissions, particularly in urban areas. This is consistent with recent measurement studies quantifying underestimations of urban NOx emissions by current emission inventories, identifying the largest discrepancies when the contribution of traffic NOx emissions is high. This study applies a high-resolution chemistry transport model in combination with ambient measurements in order to assess the potential underestimation of traffic NOx emissions in a frequently used emission inventory. The emission inventory is based on officially reported values and the Berlin-Brandenburg area in Germany is used as a case study. The WRF-Chem model is used at a 3 km × 3 km horizontal resolution, simulating the whole year of 2014. The emission data are downscaled from an original resolution of ca. 7 km × 7 km to a resolution of 1 km × 1 km. An in-depth model evaluation including spectral decomposition of observed and modelled time series and error apportionment suggests that an underestimation in traffic emissions is likely one of the main causes of the bias in modelled NO2 concentrations in the urban background, where NO2 concentrations are underestimated by ca. 8 µg m-3 (-30 %) on average over the whole year. Furthermore, a diurnal cycle of the bias in modelled NO2 suggests that a more realistic treatment of the diurnal cycle of traffic emissions might be needed. Model problems in simulating the correct mixing in the urban planetary boundary layer probably play an important role in contributing to the model bias, particularly in summer. Also taking into account this and other possible sources of model bias, a correction factor for traffic NOx emissions of ca. 3 is estimated for weekday daytime traffic emissions in the core urban area, which corresponds to an overall underestimation of traffic NOx emissions in the core urban area of ca. 50 %. Sensitivity simulations for the months of January and July using the calculated correction factor show that the weekday model bias can be improved from -8.8 µg m-3 (-26 %) to -5.4 µg m-3 (-16 %) in January on average in the urban background, and -10.3 µg m-3 (-46 %) to -7.6 µg m-3 (-34 %) in July. In addition, the negative bias of weekday NO2 concentrations downwind of the city in the rural and suburban background can be reduced from -3.4 µg m-3 (-12 %) to -1.2 µg m-3 (-4 %) in January and from -3.0 µg m-3 (-22 %) to -1.9 µg m-3 (-14 %) in July. The results and their consistency with findings from other studies suggest that more research is needed in order to more accurately understand the spatial and temporal variability in real-world NOx emissions from traffic, and apply this understanding to the inventories used in high-resolution chemical transport models.

Towards Realistic Urban Traffic Experiments Using DFROUTER: Heuristic, Validation and Extensions

PubMed Central

2017-01-01

Traffic congestion is an important problem faced by Intelligent Transportation Systems (ITS), requiring models that allow predicting the impact of different solutions on urban traffic flow. Such an approach typically requires the use of simulations, which should be as realistic as possible. However, achieving high degrees of realism can be complex when the actual traffic patterns, defined through an Origin/Destination (O-D) matrix for the vehicles in a city, remain unknown. Thus, the main contribution of this paper is a heuristic for improving traffic congestion modeling. In particular, we propose a procedure that, starting from real induction loop measurements made available by traffic authorities, iteratively refines the output of DFROUTER, which is a module provided by the SUMO (Simulation of Urban MObility) tool. This way, it is able to generate an O-D matrix for traffic that resembles the real traffic distribution and that can be directly imported by SUMO. We apply our technique to the city of Valencia, and we then compare the obtained results against other existing traffic mobility data for the cities of Cologne (Germany) and Bologna (Italy), thereby validating our approach. We also use our technique to determine what degree of congestion is expectable if certain conditions cause additional traffic to circulate in the city, adopting both a uniform pattern and a hotspot-based pattern for traffic injection to demonstrate how to regulate the overall number of vehicles in the city. This study allows evaluating the impact of vehicle flow changes on the overall traffic congestion levels. PMID:29244762

Comprehensibility of traffic signs among urban drivers in Turkey.

PubMed

Kirmizioglu, Erkut; Tuydes-Yaman, Hediye

2012-03-01

Traffic signs are commonly used traffic safety tools, mainly developed to provide crucial information in a short time to support safe drive; but the success depends on their comprehensibility by the drivers. Also, a sudden change in the traditionally used and accepted signs can cause significant safety problem, as in the case of cancellation of red oblique bars in 2004 as a part of the European Union Harmonization Process of Turkey. Having a severe traffic safety problem in Turkey, a need to assess both the comprehensibility of internationally accepted traffic signs and current level of driver education, was the main motivation behind this study. A paper-based survey study in 2009 that reached a sample of 1478 urban drivers in the City of Ankara, focused on the determination of comprehensibility of 30 selected traffic signs, which are commonly used and critical for safety, including two recently changed signs. The meaning of each sign is sought using an open-ended question format to capture different levels and types of comprehensions, which enabled the detection of "opposite" and "partially correct" answers besides "wrong" and "correct" ones. High comprehensibility of 9 control group signs shows the validity of the study. The recently changed signs are among the oppositely associated ones proving the increased risk in traffic safety and need for more aggressive campaigning to publicize them. Copyright © 2011 Elsevier Ltd. All rights reserved.

Determinant of Road Traffic Crash Fatalities in Iran: A Longitudinal Econometric Analysis.

PubMed

Rezaei, Satar; Bagheri Lankarani, Kamran; Karami Matin, Behzad; Bazyar, Mohammad; Hamzeh, Behrooz; Najafi, Farid

2015-01-01

Injuries and deaths from road traffic crashes are one of the main public health problems throughout the world. This study aimed to identify determinants of fatality traffic accident in Iran for the twenty-span year from 1991 to 2011. A time series analysis (1991-2011) was used to examine the effects of some of the key explanatory factors (GDP per capita, number of doctors per 10,000 populations, degree of urbanization, unemployment rate and motorization rate) on deaths from road traffic in Iran. In order to examine long- and short-run effects of variables, we employed autoregressive distributed lag (ARDL) approach and error correction method (ECM). The data for the study was obtained from the Central Bank of Iran (CBI), Iranian Statistical Center (ISC) and Legal medical organizations (LMO). GDP per capita, doctor per 10,000 populations, degree of urbanization and motorization rate had a significant impact on fatality from road traffic in Iran. We did not observe any short- and long-term effects of the unemployment rate on fatality from road traffic. GDP per capita, doctor per 10,000 populations, degree of urbanization and motorization rate were identified as main determinant of fatality from road traffic accidents in Iran. We hope the results of the current study enable health policy-makers to understand better the factors affecting deaths from road traffic accidents in the country.

Coordinated pre-preemption of traffic signals to enhance railroad grade crossing safety in urban areas and estimation of train impacts to arterial travel time delay.

DOT National Transportation Integrated Search

2014-01-01

This research project investigated the potential for using advanced features of traffic signal system software platforms : (ATMS.now), prevalent in Florida, to alleviate safety and mobility problems at highway-railroad at-grade crossings and : adjace...

Comprehensive evaluation of environmental and economic benefits of China's urban underground transportation construction projects.

PubMed

Yang, Xiaobin; Chen, Zhilong; Guo, Dongjun

2015-07-01

Urban underground transportation projects are introduced to address problems of scarce green land and traffic pollution. As construction of urban underground transportation is still in its infancy, there is no definite quantitative measurement on whether the construction is beneficial and what influences it will place on the region in China. This study intends to construct a comprehensive evaluation method for evaluating social, economic and environmental benefits of urban underground transportation projects and proposes the concept, role and principle for evaluation of environmental and economic benefits. It figures out relationship between the environment and factors of city development. It also summarizes three relevant factors, including transportation, biophysics and social economy, and works out indicators to evaluate the influence of urban underground transportation construction. Based on Contingent Valuation Method (CVM), Cost of Illness Approach (CIA), Human Capital Approach (HCA), this paper constructs 13 monetization calculation models for social, economic and environmental benefits in response to seven aspects, namely, reducing noise pollution and air pollution, using land efficiently, improving traffic safety, reducing traffic congestion, saving shipping time and minimizing transportation costs.

Model architecture of intelligent data mining oriented urban transportation information

NASA Astrophysics Data System (ADS)

Yang, Bogang; Tao, Yingchun; Sui, Jianbo; Zhang, Feizhou

2007-06-01

Aiming at solving practical problems in urban traffic, the paper presents model architecture of intelligent data mining from hierarchical view. With artificial intelligent technologies used in the framework, the intelligent data mining technology improves, which is more suitable for the change of real-time road condition. It also provides efficient technology support for the urban transport information distribution, transmission and display.

Emergency automatic signalling system using time scheduling

NASA Astrophysics Data System (ADS)

Rayavel, P.; Surenderanath, S.; Rathnavel, P.; Prakash, G.

2018-04-01

It is difficult to handle traffic congestion and maintain roads during traffic mainly in India. As the people migrate from rural to urban and sub-urban areas, it becomes still more critical. Presently Roadways is a standout amongst the most vital transportation. At the point when a car crash happens, crisis vehicles, for example, ambulances and fire trucks must rush to the mischance scene. There emerges a situation where a portion of the crisis vehicles may cause another car crash. Therefore it becomes still more difficult for emergency vehicle to reach the destination within a predicted time. To avoid that kind of problem we have come out with an effective idea which can reduce the potential in the traffic system. The traffic system is been modified using a wireless technology and high speed micro controller to provide smooth and clear flow of traffic for ambulance to reach the destination on time. This is achieved by using RFID Tag at the ambulance and RFID Reader at the traffic system i.e., traffic signal. This mainly deals with identifying the emergency vehicle and providing a green signal to traffic signal at time of traffic jam. — By assigning priorities to various traffic movements, we can control the traffic jam. In some moments like ambulance emergency, high delegates arrive people facing lot of trouble. To overcome this problem in this paper we propose a time priority based traffic system achieved by using RFID transmitter at the emergency vehicle and RFID receiver at the traffic system i.e., traffic signal. The signal from the emergency vehicle is sent to traffic system which after detecting it sends it to microcontroller which controls the traffic signal. If any emergency vehicle is detected the system goes to emergency system mode where signal switch to green and if it is not detected normal system mode.

Investigation of the impact of low cost traffic engineering measures on road safety in urban areas.

PubMed

Yannis, George; Kondyli, Alexandra; Georgopoulou, Xenia

2014-01-01

This paper investigates the impact of low cost traffic engineering measures (LCTEMs) on the improvement of road safety in urban areas. A number of such measures were considered, such as speed humps, woonerfs, raised intersections and other traffic calming measures, which have been implemented on one-way, one-lane roads in the Municipality of Neo Psychiko in the Greater Athens Area. Data were analysed using the before-and-after safety analysis methodology with large control group. The selected control group comprised of two Municipalities in the Athens Greater Area, which present similar road network and land use characteristics with the area considered. The application of the methodology showed that the total number of crashes presented a statistically significant reduction, which can be possibly attributed to the introduction of LCTEMs. This reduction concerns passenger cars and single-vehicle crashes and is possibly due to the behavioural improvement of drivers of 25 years old or more. The results of this research are very useful for the identification of the appropriate low cost traffic engineering countermeasures for road safety problems in urban areas.

[Traffic accidents: a qualitative approach from Campinas, São Paulo, Brazil].

PubMed

Queiroz, Marcos S; Oliveira, Patrícia C P

2002-01-01

This article takes an interdisciplinary qualitative approach to the problem of traffic accidents in Campinas, São Paulo, Brazil. The authors begin by analyzing the "municipalization" (i.e., decentralization to the municipal level) of transport and traffic management in Campinas based on social representations by members of the local government's technical staff. Data demonstrate a significant drop in traffic accident mortality in Campinas in the last ten years. The findings illustrate how new transport and traffic policies had several positive effects. Special attention is given to the objectives, strategies, and obstacles dealt with by local government in the "municipalization" of traffic. The paper concludes by emphasizing the need for specific public policies to revitalize urban mass transportation, including special traffic safety educational programs.

Spatial correlation analysis of urban traffic state under a perspective of community detection

NASA Astrophysics Data System (ADS)

Yang, Yanfang; Cao, Jiandong; Qin, Yong; Jia, Limin; Dong, Honghui; Zhang, Aomuhan

2018-05-01

Understanding the spatial correlation of urban traffic state is essential for identifying the evolution patterns of urban traffic state. However, the distribution of traffic state always has characteristics of large spatial span and heterogeneity. This paper adapts the concept of community detection to the correlation network of urban traffic state and proposes a new perspective to identify the spatial correlation patterns of traffic state. In the proposed urban traffic network, the nodes represent road segments, and an edge between a pair of nodes is added depending on the result of significance test for the corresponding correlation of traffic state. Further, the process of community detection in the urban traffic network (named GWPA-K-means) is applied to analyze the spatial dependency of traffic state. The proposed method extends the traditional K-means algorithm in two steps: (i) redefines the initial cluster centers by two properties of nodes (the GWPA value and the minimum shortest path length); (ii) utilizes the weight signal propagation process to transfer the topological information of the urban traffic network into a node similarity matrix. Finally, numerical experiments are conducted on a simple network and a real urban road network in Beijing. The results show that GWPA-K-means algorithm is valid in spatial correlation analysis of traffic state. The network science and community structure analysis perform well in describing the spatial heterogeneity of traffic state on a large spatial scale.

Effects of urban sprawl and vehicle miles traveled on traffic fatalities.

PubMed

Yeo, Jiho; Park, Sungjin; Jang, Kitae

2015-01-01

Previous research suggests that urban sprawl increases auto-dependency and that excessive auto use increases the risk of traffic fatalities. This indirect effect of urban sprawl on traffic fatalities is compared to non-vehicle miles traveled (VMT)-related direct effect of sprawl on fatalities. We conducted a path analysis to examine the causal linkages among urban sprawl, VMT, traffic fatalities, income, and fuel cost. The path diagram includes 2 major linkages: the direct relationship between urban sprawl and traffic fatalities and the indirect effect on fatalities through increased VMT in sprawling urban areas. To measure the relative strength of these causal linkages, path coefficients are estimated using data collected nationally from 147 urbanized areas in the United States. Through both direct and indirect paths, urban sprawl is associated with greater numbers of traffic fatalities, but the direct effect of sprawl on fatalities is more influential than the indirect effect. Enhancing traffic safety can be achieved by impeding urban sprawl and encouraging compact development. On the other hand, policy tools reducing VMT may be less effective than anticipated for traffic safety.

Characterization of transit ride quality.

DOT National Transportation Integrated Search

2016-08-01

Strategies often proposed to combat the growing traffic congestion problems of urban environments target enhancements to increase the use of bus transit. Therefore, service providers are keen to identify and understand factors that could attract more...

Fixed Point Learning Based Intelligent Traffic Control System

NASA Astrophysics Data System (ADS)

Zongyao, Wang; Cong, Sui; Cheng, Shao

2017-10-01

Fixed point learning has become an important tool to analyse large scale distributed system such as urban traffic network. This paper presents a fixed point learning based intelligence traffic network control system. The system applies convergence property of fixed point theorem to optimize the traffic flow density. The intelligence traffic control system achieves maximum road resources usage by averaging traffic flow density among the traffic network. The intelligence traffic network control system is built based on decentralized structure and intelligence cooperation. No central control is needed to manage the system. The proposed system is simple, effective and feasible for practical use. The performance of the system is tested via theoretical proof and simulations. The results demonstrate that the system can effectively solve the traffic congestion problem and increase the vehicles average speed. It also proves that the system is flexible, reliable and feasible for practical use.

Urban air quality

NASA Astrophysics Data System (ADS)

Fenger, Jes

Since 1950 the world population has more than doubled, and the global number of cars has increased by a factor of 10. In the same period the fraction of people living in urban areas has increased by a factor of 4. In year 2000 this will amount to nearly half of the world population. About 20 urban regions will each have populations above 10 million people. Seen over longer periods, pollution in major cities tends to increase during the built up phase, they pass through a maximum and are then again reduced, as abatement strategies are developed. In the industrialised western world urban air pollution is in some respects in the last stage with effectively reduced levels of sulphur dioxide and soot. In recent decades however, the increasing traffic has switched the attention to nitrogen oxides, organic compounds and small particles. In some cities photochemical air pollution is an important urban problem, but in the northern part of Europe it is a large-scale phenomenon, with ozone levels in urban streets being normally lower than in rural areas. Cities in Eastern Europe have been (and in many cases still are) heavily polluted. After the recent political upheaval, followed by a temporary recession and a subsequent introduction of new technologies, the situation appears to improve. However, the rising number of private cars is an emerging problem. In most developing countries the rapid urbanisation has so far resulted in uncontrolled growth and deteriorating environment. Air pollution levels are here still rising on many fronts. Apart from being sources of local air pollution, urban activities are significant contributors to transboundary pollution and to the rising global concentrations of greenhouse gasses. Attempts to solve urban problems by introducing cleaner, more energy-efficient technologies will generally have a beneficial impact on these large-scale problems. Attempts based on city planning with a spreading of the activities, on the other hand, may generate more traffic and may thus have the opposite effect.

The Evaluation of Screening Process and Local Bureaucracy in Determining the Priority of Urban Roads Maintenance and Rehabilitation

NASA Astrophysics Data System (ADS)

Hendhratmoyo, Andri; Syafi'i; Pungky Pramesti, Florentina

2017-11-01

Due to the limited budget of urban roads maintenance and rehabilitation, its prioritizationis inevitable. Many models have been developed to solve these problems. That is the reason why the purpose of this study was to evaluate the screening process in the decision making of the urban roads maintenance and rehabilitation priority. The prioritization that have to be taken into account on the effect of important criteria are road condition, traffic volume, budget processing and land use. 30 stakeholders were asked to fill in the questionnaires. The object of this case study are 188 urban roads sections at Ponorogo in order to examine the priorities. The researchers collected the data from Surface Distress Index (SDI), traffic volume, budget processing and land use of these road sections. Based on analysis, the weights of the criteria were: road condition (W1) = 0,411; traffic volume (W2) = 0,122; budget processing (W3) = 0,363 and land use (W4) = 0,105. The result of this study by the comparison of the index values of the alternatives priorities, Nyi Ageng Serang Street, was revealed to have the highest priority over the other streets regarding of maintenance and rehabilitation activities.

Urban planning and traffic safety at night

NASA Astrophysics Data System (ADS)

Ispas, N.; Trusca, D.

2016-08-01

Urban planning including traffic signs serve vital functions, providing road users with regulatory, warning and guidance information about the roadway and surrounding environment. There are a large number of signs and even more guidelines on how these signs should be designed, installed, and maintained in concordance with on road surface traffic signs. More requirements for signs are made for night urban traffic, including appearance (size, shape, colour), placement (height, lateral, and longitudinal), maintenance (visibility, position, damage) and signs light and retroreflective. In the night, traffic signs visibility can interact by on pedestrian visibility and diminish urban traffic safety. The main aim of this paper are the scientific determination of an urban specific zone visibility for evaluate at night real conditions in case of a traffic accident in the Braşov city area. The night visibility study was made using PC-Rect version 4.2. Other goal of the paper was to modify some urban planning solution in order to increase the urban safety in Brașov.

A Review of Adverse Effects of Road Traffic Noise on Human Health

NASA Astrophysics Data System (ADS)

Singh, Devi; Kumari, Neeraj; Sharma, Pooja

Noise pollution due to road traffic is a potential threat to human health. Since it is a global hazard, the rapid urbanization and exponential traffic growth have aggravated the problem. Population residing along the busy traffic lanes is continuously exposed to the sound levels which are above the permissible limits. This constant exposure to noise pollution is a cause of concern as it leads to several adverse impacts on human health. Traffic noise causes irritation and annoyance, sleep disturbances, cardiovascular disease, risk of stroke, diabetes, hypertension and loss of hearing. It results in decreased work performance. The present review highlights the serious health hazards of road traffic noise (RTN) which needs to be curbed. Preventive measures of noise pollution can help in combating noise-induced health hazards and increased work performance.

A Study on Urban Road Traffic Safety Based on Matter Element Analysis

PubMed Central

Hu, Qizhou; Zhou, Zhuping; Sun, Xu

2014-01-01

This paper examines a new evaluation of urban road traffic safety based on a matter element analysis, avoiding the difficulties found in other traffic safety evaluations. The issue of urban road traffic safety has been investigated through the matter element analysis theory. The chief aim of the present work is to investigate the features of urban road traffic safety. Emphasis was placed on the construction of a criterion function by which traffic safety achieved a hierarchical system of objectives to be evaluated. The matter element analysis theory was used to create the comprehensive appraisal model of urban road traffic safety. The technique was used to employ a newly developed and versatile matter element analysis algorithm. The matter element matrix solves the uncertainty and incompatibility of the evaluated factors used to assess urban road traffic safety. The application results showed the superiority of the evaluation model and a didactic example was included to illustrate the computational procedure. PMID:25587267

Towards smart mobility in urban spaces: Bus tracking and information application

NASA Astrophysics Data System (ADS)

Yue, Wong Seng; Chye, Koh Keng; Hoy, Cheong Wan

2017-10-01

Smart city can be defined as an urban space with complete and advanced infrastructure, intelligent networks and platforms, with millions of sensors among which people themselves and their mobile devices. Urban mobility is one of the global smart city project which offers traffic management in real-time, management of passenger transport means, tracking applications and logistics, car sharing services, car park management and more smart mobility services. Due to the frustrated waiting time for the arrival of buses and the difficulty of accessing shuttle bus-related information in a one-stop centre, bus tracking and information application (BTA) is one the proposed solutions to solve the traffic problems in urban spaces. This paper is aimed to design and develop a bus tracking and information application in a selected city in Selangor state, Malaysia. Next, this application also provides an alternative to design public transport tracking and information application for the urban places in Malaysia. Furthermore, the application also provides a smart solution for the management of public infrastructures and urban facilities in Malaysia in future.

Spatial Analysis of Urban Form and Pedestrian Exposure to Traffic Noise

PubMed Central

Sheng, Ni; Tang, U. Wa

2011-01-01

In the Macao Peninsula, the high population density (49,763 inhabitants/km2) and the lack of control over the number of vehicles (460 vehicles/km) have led to an increase in urban pollution. To provide useful information to local government and urban planners, this paper investigates the spatial distribution of traffic noise in the Macao Peninsula. The interactions among urban form, traffic flow and traffic noise are addressed. Considering the spatial nature of urban geometry and traffic, a high-resolution GIS-based traffic noise model system is applied. Results indicate that the Macao Peninsula has fallen into a situation of serious traffic noise pollution. About 60% of traffic noise levels along the major pedestrian sidewalks in the evening peak hour exceed the National Standard of 70 dB(A) in China. In particular, about 21% of traffic noise levels along the pedestrian sidewalks are above the National Standard by 5 dB(A). Noticeably, the high pedestrian exposure to traffic noise in the historical urban area reduces the comfort of tourists walking in the historic centre and is ruining the reputation of the area as a World Cultural Heritage site. PMID:21776213

Spatial analysis of urban form and pedestrian exposure to traffic noise.

PubMed

Sheng, Ni; Tang, U Wa

2011-06-01

In the Macao Peninsula, the high population density (49,763 inhabitants/km2) and the lack of control over the number of vehicles (460 vehicles/km) have led to an increase in urban pollution. To provide useful information to local government and urban planners, this paper investigates the spatial distribution of traffic noise in the Macao Peninsula. The interactions among urban form, traffic flow and traffic noise are addressed. Considering the spatial nature of urban geometry and traffic, a high-resolution GIS-based traffic noise model system is applied. Results indicate that the Macao Peninsula has fallen into a situation of serious traffic noise pollution. About 60% of traffic noise levels along the major pedestrian sidewalks in the evening peak hour exceed the National Standard of 70 dB(A) in China. In particular, about 21% of traffic noise levels along the pedestrian sidewalks are above the National Standard by 5 dB(A). Noticeably, the high pedestrian exposure to traffic noise in the historical urban area reduces the comfort of tourists walking in the historic centre and is ruining the reputation of the area as a World Cultural Heritage site.

Monitoring Street-Level Spatial-Temporal Variations of Carbon Monoxide in Urban Settings Using a Wireless Sensor Network (WSN) Framework

PubMed Central

Wen, Tzai-Hung; Jiang, Joe-Air; Sun, Chih-Hong; Juang, Jehn-Yih; Lin, Tzu-Shiang

2013-01-01

Air pollution has become a severe environmental problem due to urbanization and heavy traffic. Monitoring street-level air quality is an important issue, but most official monitoring stations are installed to monitor large-scale air quality conditions, and their limited spatial resolution cannot reflect the detailed variations in air quality that may be induced by traffic jams. By deploying wireless sensors on crossroads and main roads, this study established a pilot framework for a wireless sensor network (WSN)-based real-time monitoring system to understand street-level spatial-temporal changes of carbon monoxide (CO) in urban settings. The system consists of two major components. The first component is the deployment of wireless sensors. We deployed 44 sensor nodes, 40 transmitter nodes and four gateway nodes in this study. Each sensor node includes a signal processing module, a CO sensor and a wireless communication module. In order to capture realistic human exposure to traffic pollutants, all sensors were deployed at a height of 1.5 m on lampposts and traffic signs. The study area covers a total length of 1.5 km of Keelung Road in Taipei City. The other component is a map-based monitoring platform for sensor data visualization and manipulation in time and space. Using intensive real-time street-level monitoring framework, we compared the spatial-temporal patterns of air pollution in different time periods. Our results capture four CO concentration peaks throughout the day at the location, which was located along an arterial and nearby traffic sign. The hourly average could reach 5.3 ppm from 5:00 pm to 7:00 pm due to the traffic congestion. The proposed WSN-based framework captures detailed ground information and potential risk of human exposure to traffic-related air pollution. It also provides street-level insights into real-time monitoring for further early warning of air pollution and urban environmental management. PMID:24287859

Monitoring street-level spatial-temporal variations of carbon monoxide in urban settings using a wireless sensor network (WSN) framework.

PubMed

Wen, Tzai-Hung; Jiang, Joe-Air; Sun, Chih-Hong; Juang, Jehn-Yih; Lin, Tzu-Shiang

2013-11-27

Air pollution has become a severe environmental problem due to urbanization and heavy traffic. Monitoring street-level air quality is an important issue, but most official monitoring stations are installed to monitor large-scale air quality conditions, and their limited spatial resolution cannot reflect the detailed variations in air quality that may be induced by traffic jams. By deploying wireless sensors on crossroads and main roads, this study established a pilot framework for a wireless sensor network (WSN)-based real-time monitoring system to understand street-level spatial-temporal changes of carbon monoxide (CO) in urban settings. The system consists of two major components. The first component is the deployment of wireless sensors. We deployed 44 sensor nodes, 40 transmitter nodes and four gateway nodes in this study. Each sensor node includes a signal processing module, a CO sensor and a wireless communication module. In order to capture realistic human exposure to traffic pollutants, all sensors were deployed at a height of 1.5 m on lampposts and traffic signs. The study area covers a total length of 1.5 km of Keelung Road in Taipei City. The other component is a map-based monitoring platform for sensor data visualization and manipulation in time and space. Using intensive real-time street-level monitoring framework, we compared the spatial-temporal patterns of air pollution in different time periods. Our results capture four CO concentration peaks throughout the day at the location, which was located along an arterial and nearby traffic sign. The hourly average could reach 5.3 ppm from 5:00 pm to 7:00 pm due to the traffic congestion. The proposed WSN-based framework captures detailed ground information and potential risk of human exposure to traffic-related air pollution. It also provides street-level insights into real-time monitoring for further early warning of air pollution and urban environmental management.

An integrated methodology to assess the benefits of urban green space.

PubMed

De Ridder, K; Adamec, V; Bañuelos, A; Bruse, M; Bürger, M; Damsgaard, O; Dufek, J; Hirsch, J; Lefebre, F; Pérez-Lacorzana, J M; Thierry, A; Weber, C

2004-12-01

The interrelated issues of urban sprawl, traffic congestion, noise, and air pollution are major socioeconomic problems faced by most European cities. A methodology is currently being developed for evaluating the role of green space and urban form in alleviating the adverse effects of urbanisation, mainly focusing on the environment but also accounting for socioeconomic aspects. The objectives and structure of the methodology are briefly outlined and illustrated with preliminary results obtained from case studies performed on several European cities.

Statistical Methods for Passive Vehicle Classification in Urban Traffic Surveillance and Control

DOT National Transportation Integrated Search

1980-01-01

A statistical approach to passive vehicle classification using the phase-shift signature from electromagnetic presence-type vehicle detectors is developed with digitized samples of the analog phase-shift signature, the problem of classifying vehicle ...

Environmental impacts of urban snow management--the alpine case study of Innsbruck.

PubMed

Engelhard, C; De Toffol, S; Lek, I; Rauch, W; Dallinger, R

2007-09-01

In regions with colder climate, snow at roads can accumulate significant amounts of pollutant chemicals. In northern countries various efforts have been made to face this problem, but for the alpine region little is known about the pollution of urban snow. The present case study was carried out in the city of Innsbruck (Austria). It aimed at measuring pollution of roadside snow and estimating the impact of snow management practises on environmental quality. Concentrations of copper, zinc, lead, cadmium, suspended solids and chloride were determined during a series of sampling events. Various locations with low and high traffic densities and in different distances from a highway have been investigated. The concentrations of copper were generally higher at sites with high traffic density compared to locations with low traffic impact. In contrast to this, the concentrations of zinc and lead remained almost unvaried irrespective of traffic density at the different sampling sites. For cadmium, the picture was more diverse, showing moderately elevated concentrations of this metal also at the urban reference site not polluted by traffic. This indicates that there may be also other important sources for cadmium besides traffic. Suspended solids accumulated in the roadside snow, the highest concentrations were found at the sites with high traffic density. The chloride concentrations were considerable in the snow, especially at the highway. Based on the results of the present measurement campaign, the environmental impact of snow disposal in rivers was also estimated. A negative impact on rivers from snow disposal seems likely to occur, although the discharged loads could only be calculated with substantial uncertainty, considering the high variability of the measured pollutant concentrations. For a more accurate evaluation of this management practise on rivers, further investigations would be necessary.

Social dilemma structure hidden behind traffic flow with route selection

NASA Astrophysics Data System (ADS)

Tanimoto, Jun; Nakamura, Kousuke

2016-10-01

Several traffic flows contain social dilemma structures. Herein, we explored a route-selection problem using a cellular automaton simulation dovetailed with evolutionary game theory. In our model, two classes of driver-agents coexist: D agents (defective strategy), which refer to traffic information for route selection to move fast, and C agents (cooperative strategy), which are insensitive to information and less inclined to move fast. Although no evidence suggests that the social dilemma structure in low density causes vehicles to move freely and that in high density causes traffic jams, we found a structure that corresponds to an n-person (multiplayer) Chicken (n-Chicken) game if the provided traffic information is inappropriate. If appropriate traffic information is given to the agents, the n-Chicken game can be solved. The information delivered to vehicles is crucial for easing the social dilemma due to urban traffic congestion when developing technologies to support the intelligent transportation system (ITS).

A population study on risk factors for insomnia among adult Japanese women: a possible effect of road traffic volume.

PubMed

Kageyama, T; Kabuto, M; Nitta, H; Kurokawa, Y; Taira, K; Suzuki, S; Takemoto, T

1997-11-01

In an effort to identify risk factors for insomnia and determine the contribution of nightime road traffic volume to insomnia in the general population, a questionnaire survey was carried out among 3,600 adult Japanese women living in eight urban residential areas. The crude prevalence rate of insomnia was 11.2%. Multivariate analysis revealed that aging, living with a child/children aged six or younger, undergoing medical treatment, experiencing major life events, having an irregular bedtime, having a sleep apnealike symptom, and living near a road with a heavy volume of traffic are risk factors for insomnia. Taking into account other risk factors, there was a level-response relationship between the nighttime traffic volume of main roads and the risk of insomnia in the subjects living in the zones 0-20 m from these roads. These results suggest that road traffic noise raises the sound level in bedrooms in such zones, and consequently the prevalence rate of insomnia among the residents, and that noise-induced insomnia is an important public health problem, at least in highly urbanized areas. To confirm this, a further study on noise exposure is needed.

A case study predicting environmental impacts of urban transport planning in China.

PubMed

Chen, Chong; Shao, Li-guo; Xu, Ling; Shang, Jin-cheng

2009-10-01

Predicting environmental impacts is essential when performing an environmental assessment on urban transport planning. System dynamics (SD) is usually used to solve complex nonlinear problems. In this study, we utilized system dynamics (SD) to evaluate the environmental impacts associated with urban transport planning in Jilin City, China with respect to the local economy, society, transport, the environment and resources. To accomplish this, we generated simulation models comprising interrelated subsystems designed to utilize changes in the economy, society, road construction, changes in the number of vehicles, the capacity of the road network capacity, nitrogen oxides emission, traffic noise, land used for road construction and fuel consumption associated with traffic to estimate dynamic trends in the environmental impacts associated with Jilin's transport planning. Two simulation scenarios were then analyzed comparatively. The results of this study indicated that implementation of Jilin transport planning would improve the current urban traffic conditions and boost the local economy and development while benefiting the environment in Jilin City. In addition, comparative analysis of the two scenarios provided additional information that can be used to aid in scientific decision-making regarding which aspects of the transport planning to implement in Jilin City. This study demonstrates that our application of the SD method, which is referred to as the Strategic Environmental Assessment (SEA), is feasible for use in urban transport planning.

Understanding urban travel demand : problems, solutions, and the role of forecasting

DOT National Transportation Integrated Search

1999-08-01

This report is a general examination and critique of transportation policy making, focusing on the role of traffic and land use forecasting. There are four major components: (1) Current, historical, and projected travel behavior in the Twin Cities; (...

Commuting, congestion, and pollution : the employer-paid parking connection

DOT National Transportation Integrated Search

1992-09-01

Urban areas increasingly face problems associated with traffic congestion and vehicle air emissions. Employer-paid parking--a form of matching grant whereby an employer offers to pay the cost of parking if employees are willing to pay all other costs...

Heterogeneity Index for the Assessment of Relationship Between Land Use Pattern and Road Traffic Congestion in Apapa-Oworoshoki Express way, Lagos Metropolis

NASA Astrophysics Data System (ADS)

Alaigba, D. B.; Soumah, M.; Banjo, M. O.

2017-05-01

The problem of urban mobility is complicated by traffic delay, resulting from poor planning, high population density and poor condition of roads within urban spaces. This study assessed traffic congestion resulting from differential contribution made by various land-uses along Apapa-Oworoshoki expressway in Lagos metropolis. The data for this study was from both primary and secondary sources; GPS point data was collected at selected points for traffic volume count; observation of the nature of vehicular traffic congestion, and land use types along the corridor. Existing data on traffic count along the corridor, connectivity map and land use map sourced from relevant authorities were acquired. Traffic congestion within the area was estimated using volume capacity ratio (V/C). Heterogeneity Index was developed and used to quantify the percentage contribution to traffic volume from various land-use categories. Analytical Hierarchical Processing (AHP) and knowledge-based weighting were used to rank the importance of different heterogeneity indices. Results showed significant relationship between the degree of heterogeneity of the land use pattern and road traffic congestion. Volume Capacity Ratio computed revealed that the route corridor exceeds its designed capacity in the southward direction between the hours of 8am and 12pm on working days. Five major nodes were analyzed along the corridor, and were all above the expected Passenger Car Unit (PCU), these are "Oshodi" 15 %, "Airport junction" 10 %, "Cele bus stop" 21 %, "Mile 2" 14 %, "Berger" 15 % and "Tincan bus stop" 33 % indicating heavy traffic congestion.

An evaluation of congestion-reducing measures used in Virginia.

DOT National Transportation Integrated Search

1992-01-01

Congestion on our nation's highways, especially in urban areas, is a serious problem that is growing steadily worse. In Virginia, it is estimated that 28 percent of the daily vehicle miles of travel (VMT) occurring during peak hour traffic is congest...

Android-based E-Traffic law enforcement system in Surakarta City

NASA Astrophysics Data System (ADS)

Yulianto, Budi; Setiono

2018-03-01

The urban advancement is always overpowered by the increasing number of vehicles as the need for movement of people and goods. This can lead to traffic problems if there is no effort on the implementation of traffic management and engineering, and traffic law enforcement. In this case, the Government of Surakarta City has implemented various policies and regulations related to traffic management and engineering in order to run traffic in an orderly, safe and comfortable manner according to the applicable law. However, conditions in the field shows that traffic violations still occurred frequently due to the weakness of traffic law enforcement in terms of human resources and the system. In this connection, a tool is needed to support traffic law enforcement, especially in relation to the reporting system of traffic violations. This study aims to develop an Android-based traffic violations reporting application (E-Traffic Law Enforcement) as part of the traffic law enforcement system in Surakarta City. The Android-apps records the location and time of the traffic violations incident along with the visual evidence of the infringement. This information will be connected to the database system to detect offenders and to do the traffic law enforcement process.

Effects of canyon geometry on the distribution of traffic-related air pollution in a large urban area: Implications of a multi-canyon air pollution dispersion model

NASA Astrophysics Data System (ADS)

Fu, Xiangwen; Liu, Junfeng; Ban-Weiss, George A.; Zhang, Jiachen; Huang, Xin; Ouyang, Bin; Popoola, Olalekan; Tao, Shu

2017-09-01

Street canyons are ubiquitous in urban areas. Traffic-related air pollutants in street canyons can adversely affect human health. In this study, an urban-scale traffic pollution dispersion model is developed considering street distribution, canyon geometry, background meteorology, traffic assignment, traffic emissions and air pollutant dispersion. In the model, vehicle exhausts generated from traffic flows first disperse inside street canyons along the micro-scale wind field generated by computational fluid dynamics (CFD) model. Then, pollutants leave the street canyon and further disperse over the urban area. On the basis of this model, the effects of canyon geometry on the distribution of NOx and CO from traffic emissions were studied over the center of Beijing. We found that an increase in building height leads to heavier pollution inside canyons and lower pollution outside canyons at pedestrian level, resulting in higher domain-averaged concentrations over the area. In addition, canyons with highly even or highly uneven building heights on each side of the street tend to lower the urban-scale air pollution concentrations at pedestrian level. Further, increasing street widths tends to lead to lower pollutant concentrations by reducing emissions and enhancing ventilation simultaneously. Our results indicate that canyon geometry strongly influences human exposure to traffic pollutants in the populated urban area. Carefully planning street layout and canyon geometry while considering traffic demand as well as local weather patterns may significantly reduce inhalation of unhealthy air by urban residents.

A Numerical Simulation of Traffic-Related Air Pollution Exposures in Urban Street Canyons

NASA Astrophysics Data System (ADS)

Liu, J.; Fu, X.; Tao, S.

2016-12-01

Urban street canyons are usually associated with intensive vehicle emissions. However, the high buildings successively along both sides of a street block the dispersion of traffic-generated air pollutants, which enhances human exposure and adversely affects human health. In this study, an urban scale traffic pollution dispersion model is developed with the consideration of street distribution, canyon geometry, background meteorology, traffic assignment, traffic emissions and air pollutant dispersion. Vehicle exhausts generated from traffic flows will first disperse inside a street canyon along the micro-scale wind field (generated by computational fluid dynamics (CFD) model) and then leave the street canyon and further disperse over the urban area. On the basis of this model, the effects of canyon geometry on the distribution of NOx and CO from traffic emissions were studied over the center of Beijing, China. We found that an increase of building height along the streets leads to higher pollution levels inside streets and lower pollution levels outside, resulting in higher domain-averaged concentrations over the area. In addition, street canyons with equal (or highly uneven) building heights on two sides of a street tend to lower the urban-scale air pollution concentrations at pedestrian level. Our results indicate that canyon geometry strongly influences human exposure to traffic pollutants in the populated urban area. Carefully planning street layout and canyon geometry in consideration of traffic demand as well as local weather pattern may significantly reduce the chances of unhealthy air being inhaled by urban residents.

Carbon dioxide emission and bio-capacity indexing for transportation activities: A methodological development in determining the sustainability of vehicular transportation systems.

PubMed

Labib, S M; Neema, Meher Nigar; Rahaman, Zahidur; Patwary, Shahadath Hossain; Shakil, Shahadat Hossain

2018-06-09

CO 2 emissions from urban traffic are a major concern in an era of increasing ecological disequilibrium. Adding to the problem net CO 2 emissions in urban settings are worsened due to the decline of bio-productive areas in many cities. This decline exacerbates the lack of capacity to sequestrate CO 2 at the micro and meso-scales resulting in increased temperatures and decreased air quality within city boundaries. Various transportation and environmental strategies have been implemented to address traffic related CO 2 emissions, however current literature identifies difficulties in pinpointing these critical areas of maximal net emissions in urban transport networks. This study attempts to close this gap in the literature by creating a new lay-person friendly index that combines CO 2 emissions from vehicles and the bio-capacity of specific traffic zones to identify these areas at the meso-scale within four ranges of values with the lowest index values representing the highest net CO 2 levels. The study used traffic volume, fuel types, and vehicular travel distance to estimate CO 2 emissions at major links in Dhaka, Bangladesh's capital city's transportation network. Additionally, using remote-sensing tools, adjacent bio-productive areas were identified and their bio-capacity for CO 2 sequestration estimated. The bio-productive areas were correlated with each traffic zone under study resulting in an Emission Bio-Capacity index (EBI) value estimate for each traffic node. Among the ten studied nodes in Dhaka City, nine had very low EBI values, correlating to very high CO 2 emissions and low bio-capacity. As a result, the study considered these areas unsustainable as traffic nodes going forward. Key reasons for unsustainability included increasing use of motorized traffic, absence of optimized signal systems, inadequate public transit options, disincentives for fuel free transport (FFT), and a decline in bio-productive areas. Copyright © 2018 Elsevier Ltd. All rights reserved.

Policy Choice for Urban Low-carbon transportation in Beijing: Scenario Analysis Based on LEAP model

NASA Astrophysics Data System (ADS)

Zhang, Yu

2016-04-01

Beijing is a fast developing megacity with serious traffic problems, such as high energy consumption, high CO2 emission and traffic congestion. The coming 13th Five-Year Plan for Beijing economic and social development will focus on the low-carbon transportation policy to achieve the urban traffic sustainable development. In order to improve the feasibility of urban low-carbon transportation policies, this paper analyzes the future trends of CO2 emissions from transportation of Beijing. Firstly, five policies scenarios are developed according to the coming Beijing 13th Five-Year Plan, including the "Business As Usual (BAU)", the "Public Transportation Priority(PTP)", the "New Energy Vehicle(NEV)", the "Active Transportation(AT)", the "Private Car Regulation(PCR)" and the "Hybrid Policy(HP)". Then the Long-range Energy Alternatives Planning System(LEAP model) framework is adopted to estimate CO2 emission under given policies scenarios up to year 2020 and analyze the implications. The results demonstrate that the low-carbon transportation policies can reduce CO2 emission effectively. Specifically, the "Hybrid Policy(HP)" has the best performance. In terms of single policy effect, the "Private Car Regulation(PCR)" comes first followed by the "Public Transportation Priority(PTP)".

Predictability of Road Traffic and Congestion in Urban Areas

PubMed Central

Wang, Jingyuan; Mao, Yu; Li, Jing; Xiong, Zhang; Wang, Wen-Xu

2015-01-01

Mitigating traffic congestion on urban roads, with paramount importance in urban development and reduction of energy consumption and air pollution, depends on our ability to foresee road usage and traffic conditions pertaining to the collective behavior of drivers, raising a significant question: to what degree is road traffic predictable in urban areas? Here we rely on the precise records of daily vehicle mobility based on GPS positioning device installed in taxis to uncover the potential daily predictability of urban traffic patterns. Using the mapping from the degree of congestion on roads into a time series of symbols and measuring its entropy, we find a relatively high daily predictability of traffic conditions despite the absence of any priori knowledge of drivers' origins and destinations and quite different travel patterns between weekdays and weekends. Moreover, we find a counterintuitive dependence of the predictability on travel speed: the road segment associated with intermediate average travel speed is most difficult to be predicted. We also explore the possibility of recovering the traffic condition of an inaccessible segment from its adjacent segments with respect to limited observability. The highly predictable traffic patterns in spite of the heterogeneity of drivers' behaviors and the variability of their origins and destinations enables development of accurate predictive models for eventually devising practical strategies to mitigate urban road congestion. PMID:25849534

Street floods in Metro Manila and possible solutions.

PubMed

Lagmay, Alfredo Mahar; Mendoza, Jerico; Cipriano, Fatima; Delmendo, Patricia Anne; Lacsamana, Micah Nieves; Moises, Marc Anthony; Pellejera, Nicanor; Punay, Kenneth Niño; Sabio, Glenn; Santos, Laurize; Serrano, Jonathan; Taniza, Herbert James; Tingin, Neil Eneri

2017-09-01

Urban floods from thunderstorms cause severe problems in Metro Manila due to road traffic. Using Light Detection and Ranging (LiDAR)-derived topography, flood simulations and anecdotal reports, the root of surface flood problems in Metro Manila is identified. Majority of flood-prone areas are along the intersection of creeks and streets located in topographic lows. When creeks overflow or when rapidly accumulated street flood does not drain fast enough to the nearest stream channel, the intersecting road also gets flooded. Possible solutions include the elevation of roads or construction of well-designed drainage structures leading to the creeks. Proposed solutions to the flood problem of Metro Manila may avoid paralyzing traffic problems due to short-lived rain events, which according to Japan International Cooperation Agency (JICA) cost the Philippine economy 2.4billionpesos/day. Copyright © 2017. Published by Elsevier B.V.

Factor Analysis of Traffic Safety in Urban Roads Based on FTA-LEC

NASA Astrophysics Data System (ADS)

Shuicheng, TIAN; Xingbo, YANG; Xiaoqing, SHEN; Detao, ZHANG

2018-05-01

In order to reduce the number and the loss of urban road traffic accidents in our country, improve the safety of road traffic, a statistical analysis of the research report on major road traffic accidents in 2016 was conducted. The risk factors affecting urban road traffic in China were analyzed by using FTA to find the basic hidden events. Secondly, the risk value of the identified hidden danger events were calculated and classified into four levels I, II, III and IV through the LEC evaluation method. Finally, the graded results of risk factors are verified through a case of specific accidents in Beijing. The results show that: the case verified the scientificalness and effectiveness of hazard classification and provided guidance for urban road traffic management.

Definition of perspective scheme of organization of traffic using methods of forecasting and modeling

NASA Astrophysics Data System (ADS)

Vlasov, V. M.; Novikov, A. N.; Novikov, I. A.; Shevtsova, A. G.

2018-03-01

In the environment of highly developed urban agglomerations, one of the main problems arises - inability of the road network to reach a high level of motorization. The introduction of intelligent transport systems allows solving this problem, but the main issue in their implementation remains open: to what extent this or that method of improving the transport network will be effective and whether it is able to solve the problem of vehicle growth especially for the long-term period. The main goal of this work was the development of an approach to forecasting the increase in the intensity of traffic flow for a long-term period using the population and the level of motorization. The developed approach made it possible to determine the projected population and, taking into account the level of motorization, to determine the growth factor of the traffic flow intensity, which allows calculating the intensity value for a long-term period with high accuracy. The analysis of the main methods for predicting the characteristics of the transport stream is performed. The basic values and parameters necessary for their use are established. The analysis of the urban settlement is carried out and the level of motorization characteristic for the given locality is determined. A new approach to predicting the intensity of the traffic flow has been developed, which makes it possible to predict the change in the transport situation in the long term in high accuracy. Calculations of the magnitude of the intensity increase on the basis of the developed forecasting method are made and the errors in the data obtained are determined. The main recommendations on the use of the developed forecasting approach for the long-term functioning of the road network are formulated.

Rural-urban disparity in knowledge and compliance with traffic signs among young commercial motorcyclists in selected local government areas in Oyo State, Nigeria.

PubMed

Olumide, Adesola O; Owoaje, Eme T

2017-06-01

This study compared knowledge and compliance with traffic signs among young commercial motorcyclists in rural and urban communities in Oyo state, Nigeria. Information on knowledge and compliance with 10 common traffic signs was obtained from 149 rural and 113 urban commercial motorcyclists aged 18-35 years. Aggregate knowledge scores were computed and categorized as good (≥5) and poor (<5) knowledge. Overall, 98.7% rural versus 61.1% urban motorcyclists had poor knowledge of traffic signs (p < 0.05). After controlling for age, level of education and years of commercial riding, motorcyclists in the rural areas were more likely to have poor knowledge of the traffic signs (OR = 58.15; 95% CI = 11.96-282.79). A higher proportion of rural than urban motorcyclists never obeyed any of the traffic signs. Young rural commercial motorcyclists' knowledge and compliance with the road signs was poorer than their urban counterparts. Interventions to improve the rural motorcyclists' knowledge and ultimately compliance with road signs are urgently required.

Applicability of models to estimate traffic noise for urban roads.

PubMed

Melo, Ricardo A; Pimentel, Roberto L; Lacerda, Diego M; Silva, Wekisley M

2015-01-01

Traffic noise is a highly relevant environmental impact in cities. Models to estimate traffic noise, in turn, can be useful tools to guide mitigation measures. In this paper, the applicability of models to estimate noise levels produced by a continuous flow of vehicles on urban roads is investigated. The aim is to identify which models are more appropriate to estimate traffic noise in urban areas since several models available were conceived to estimate noise from highway traffic. First, measurements of traffic noise, vehicle count and speed were carried out in five arterial urban roads of a brazilian city. Together with geometric measurements of width of lanes and distance from noise meter to lanes, these data were input in several models to estimate traffic noise. The predicted noise levels were then compared to the respective measured counterparts for each road investigated. In addition, a chart showing mean differences in noise between estimations and measurements is presented, to evaluate the overall performance of the models. Measured Leq values varied from 69 to 79 dB(A) for traffic flows varying from 1618 to 5220 vehicles/h. Mean noise level differences between estimations and measurements for all urban roads investigated ranged from -3.5 to 5.5 dB(A). According to the results, deficiencies of some models are discussed while other models are identified as applicable to noise estimations on urban roads in a condition of continuous flow. Key issues to apply such models to urban roads are highlighted.

Consideration of Exposures to Traffic-Related Air Pollution with Smart Growth Development

EPA Science Inventory

We address the near-road pollution problem as it relates to smart growth design strategies. Studies have shown that pollution levels tend to be high near heavily traveled roads and that road proximity is related to adverse health effects. These findings can conflict with urban ...

A Review of Urban Low-carbon Traffic Assessment

NASA Astrophysics Data System (ADS)

Chen, Jing; Yao, Jingjing

2017-12-01

Transportation not only promote social and economic development, but also improve people’s living standards, but its high energy consumption and high pollution brought a series of energy and environmental problems. In order to reduce the impact on the environment, countries are developing low-carbon transport as part of the socio-economic development mentioned on the agenda. On the basis of understanding the background and connotation of low-carbon transportation, this paper reviews and collates the evaluation index system and evaluation method of urban low-carbon transportation, which is used to provide reference for urban low-carbon transportation research.

Modeling the heterogeneous traffic correlations in urban road systems using traffic-enhanced community detection approach

NASA Astrophysics Data System (ADS)

Lu, Feng; Liu, Kang; Duan, Yingying; Cheng, Shifen; Du, Fei

2018-07-01

A better characterization of the traffic influence among urban roads is crucial for traffic control and traffic forecasting. The existence of spatial heterogeneity imposes great influence on modeling the extent and degree of road traffic correlation, which is usually neglected by the traditional distance based method. In this paper, we propose a traffic-enhanced community detection approach to spatially reveal the traffic correlation in city road networks. First, the road network is modeled as a traffic-enhanced dual graph with the closeness between two road segments determined not only by their topological connection, but also by the traffic correlation between them. Then a flow-based community detection algorithm called Infomap is utilized to identify the road segment clusters. Evaluated by Moran's I, Calinski-Harabaz Index and the traffic interpolation application, we find that compared to the distance based method and the community based method, our proposed traffic-enhanced community based method behaves better in capturing the extent of traffic relevance as both the topological structure of the road network and the traffic correlations among urban roads are considered. It can be used in more traffic-related applications, such as traffic forecasting, traffic control and guidance.

Traffic management teams : a description and action plan for Virginia.

DOT National Transportation Integrated Search

1988-01-01

A traffic management team improves the overall traffic operations in an urban area, especially along urban corridors, through the communication, coordination, and cooperation of the transportation-related operational agencies in the area. Since vario...

Is Traffic Still an Important Emitter of Monoaromatic Organic Compounds in European Urban Areas?

PubMed

Borbon, Agnès; Boynard, Anne; Salameh, Thérèse; Baudic, Alexia; Gros, Valérie; Gauduin, Julie; Perrussel, Olivier; Pallares, Cyril

2018-01-16

Trends of long-term observations and emission inventories suggest that traffic emissions will no longer dominate the concentrations of monoaromatic compounds (i.e., TEX - toluene, xylenes, and ethylbenzene) in European urban areas. But the split limit between traffic and other emission sector contributions such as solvent use remains tenuous. Here long-term observations of an extensive set of hydrocarbons, including TEX, at traffic and urban background sites in London, Paris and Strasbourg were combined to estimate the relative importance of traffic emissions on TEX in every city. When analyzing the urban enhancement emission ratios of TEX-to-benzene on a seasonal basis, two potential source signatures other than traffic could be differentiated in all cities (1) summertime evaporation from fuel and/or solvent and (2) wintertime domestic heating. However, traffic emissions still unambiguously dominate the concentration levels of TEX in every city despite the reduction of their emissions at exhaust pipe over the last two decades. Traffic explains between 60% and 96% (at ±20%) of TEX levels while it is less clear for xylenes at some locations. Our results provide a basis to evaluate regional emission inventories. The method is applicable at any urban area where speciated hydrocarbon monitoring is available.

A Cyber-ITS Framework for Massive Traffic Data Analysis Using Cyber Infrastructure

PubMed Central

Fontaine, Michael D.

2013-01-01

Traffic data is commonly collected from widely deployed sensors in urban areas. This brings up a new research topic, data-driven intelligent transportation systems (ITSs), which means to integrate heterogeneous traffic data from different kinds of sensors and apply it for ITS applications. This research, taking into consideration the significant increase in the amount of traffic data and the complexity of data analysis, focuses mainly on the challenge of solving data-intensive and computation-intensive problems. As a solution to the problems, this paper proposes a Cyber-ITS framework to perform data analysis on Cyber Infrastructure (CI), by nature parallel-computing hardware and software systems, in the context of ITS. The techniques of the framework include data representation, domain decomposition, resource allocation, and parallel processing. All these techniques are based on data-driven and application-oriented models and are organized as a component-and-workflow-based model in order to achieve technical interoperability and data reusability. A case study of the Cyber-ITS framework is presented later based on a traffic state estimation application that uses the fusion of massive Sydney Coordinated Adaptive Traffic System (SCATS) data and GPS data. The results prove that the Cyber-ITS-based implementation can achieve a high accuracy rate of traffic state estimation and provide a significant computational speedup for the data fusion by parallel computing. PMID:23766690

A Cyber-ITS framework for massive traffic data analysis using cyber infrastructure.

PubMed

Xia, Yingjie; Hu, Jia; Fontaine, Michael D

2013-01-01

Traffic data is commonly collected from widely deployed sensors in urban areas. This brings up a new research topic, data-driven intelligent transportation systems (ITSs), which means to integrate heterogeneous traffic data from different kinds of sensors and apply it for ITS applications. This research, taking into consideration the significant increase in the amount of traffic data and the complexity of data analysis, focuses mainly on the challenge of solving data-intensive and computation-intensive problems. As a solution to the problems, this paper proposes a Cyber-ITS framework to perform data analysis on Cyber Infrastructure (CI), by nature parallel-computing hardware and software systems, in the context of ITS. The techniques of the framework include data representation, domain decomposition, resource allocation, and parallel processing. All these techniques are based on data-driven and application-oriented models and are organized as a component-and-workflow-based model in order to achieve technical interoperability and data reusability. A case study of the Cyber-ITS framework is presented later based on a traffic state estimation application that uses the fusion of massive Sydney Coordinated Adaptive Traffic System (SCATS) data and GPS data. The results prove that the Cyber-ITS-based implementation can achieve a high accuracy rate of traffic state estimation and provide a significant computational speedup for the data fusion by parallel computing.

Traffic Surveillance Data Processing in Urban Freeway Corridors Using Kalman Filter Techniques

DOT National Transportation Integrated Search

1978-11-01

Real-time surveillance of traffic conditions on urban freeway corridors using spatially discrete presence detectors is addressed. Using a finite-dimensional (macroscopic) fluid-analog model for freeway vehicular traffic flow, an extended Kalman filte...

Assessment of honking impact on traffic noise in urban traffic environment of Nagpur, India.

PubMed

Vijay, Ritesh; Sharma, Asheesh; Chakrabarti, Tapan; Gupta, Rajesh

2015-01-01

In context of increasing traffic noise in urban India, the objective of the research study is to assess noise due to heterogeneous traffic conditions and the impact of honking on it. Traffic volume, noise levels, honking, road geometry and vehicular speed were measured on national highway, major and minor roads in Nagpur, India. Initial study showed lack of correlation between traffic volume and equivalent noise due to some factors, later identified as honking, road geometry and vehicular speed. Further, frequency analysis of traffic noise showed that honking contributed an additional 2 to 5 dB (A) noise, which is quite significant. Vehicular speed was also found to increase traffic noise. Statistical method of analysis of variance (ANOVA) confirms that frequent honking (p < 0.01) and vehicular speed (p < 0.05) have substantial impact on traffic noise apart from traffic volume and type of road. The study suggests that honking must also be a component in traffic noise assessment and to identify and monitor "No Honking" zones in urban agglomerations.

Increasing Intelligence in Inter-Vehicle Communications to Reduce Traffic Congestions: Experiments in Urban and Highway Environments.

PubMed

Meneguette, Rodolfo I; Filho, Geraldo P R; Guidoni, Daniel L; Pessin, Gustavo; Villas, Leandro A; Ueyama, Jó

2016-01-01

Intelligent Transportation Systems (ITS) rely on Inter-Vehicle Communication (IVC) to streamline the operation of vehicles by managing vehicle traffic, assisting drivers with safety and sharing information, as well as providing appropriate services for passengers. Traffic congestion is an urban mobility problem, which causes stress to drivers and economic losses. In this context, this work proposes a solution for the detection, dissemination and control of congested roads based on inter-vehicle communication, called INCIDEnT. The main goal of the proposed solution is to reduce the average trip time, CO emissions and fuel consumption by allowing motorists to avoid congested roads. The simulation results show that our proposed solution leads to short delays and a low overhead. Moreover, it is efficient with regard to the coverage of the event and the distance to which the information can be propagated. The findings of the investigation show that the proposed solution leads to (i) high hit rate in the classification of the level of congestion, (ii) a reduction in average trip time, (iii) a reduction in fuel consumption, and (iv) reduced CO emissions.

Increasing Intelligence in Inter-Vehicle Communications to Reduce Traffic Congestions: Experiments in Urban and Highway Environments

PubMed Central

Filho, Geraldo P. R.; Guidoni, Daniel L.; Pessin, Gustavo; Villas, Leandro A.; Ueyama, Jó

2016-01-01

Intelligent Transportation Systems (ITS) rely on Inter-Vehicle Communication (IVC) to streamline the operation of vehicles by managing vehicle traffic, assisting drivers with safety and sharing information, as well as providing appropriate services for passengers. Traffic congestion is an urban mobility problem, which causes stress to drivers and economic losses. In this context, this work proposes a solution for the detection, dissemination and control of congested roads based on inter-vehicle communication, called INCIDEnT. The main goal of the proposed solution is to reduce the average trip time, CO emissions and fuel consumption by allowing motorists to avoid congested roads. The simulation results show that our proposed solution leads to short delays and a low overhead. Moreover, it is efficient with regard to the coverage of the event and the distance to which the information can be propagated. The findings of the investigation show that the proposed solution leads to (i) high hit rate in the classification of the level of congestion, (ii) a reduction in average trip time, (iii) a reduction in fuel consumption, and (iv) reduced CO emissions PMID:27526048

Solutions to Improve Road Circulation in the Pitesti City Based on Analysis-Diagnostics of Road Traffic

NASA Astrophysics Data System (ADS)

Vîlcan, A.; Neagu, E.; Badarau Suster, H.; Boroiu, A. A.

2017-10-01

Road traffic congestion has become a daily phenomenon in the central area of Pitesti in the peak traffic periods. In order to achieve the mobility plan of Pitesti, an important stage is the diagnostic analysis of the road traffic. For this purpose, the urban road network was formalized through a graph containing the most important 40 intersections and traffic measurements were made at all these intersections and on the main roads connecting the peri-urban area. The data obtained by traffic macrosimulation confirmed the overloading of the street network during peak traffic hours and the analyzes made for various road traffic organization scenarios have shown that there are sustainable solutions for urban mobility only if the road network is fundamentally reconfigured (a belt outside the city and a median ring). Thus, the necessity of realizing the road passage in the Prundu neighbourhood and the finishing of the city belt by realizing the “detour West” of the city is argued. The importance of the work is that it brings scientific arguments for the realization of these road infrastructure projects, integrated in the urban mobility plan, which will base the development strategy of the Pitesti municipality.

Assessment of annoyance due to urban road traffic noise combined with tramway noise.

PubMed

Klein, A; Marquis-Favre, C; Champelovier, P

2017-01-01

Due to the expansion of urban areas, an increasing number of residents are exposed to combined community noise sources. Studies show that the exposure to transportation noise significantly affects health and well-being. Noise annoyance is one of these adverse health effects. Up to now, annoyance due to transportation noise is mostly assessed considering single noise exposure situations neglecting the effects of potential interactions between noise sources. In this study, perceptual phenomena involved in noise annoyance due to combined urban road traffic and tramway noises are assessed in laboratory conditions with imaginary and simulated contexts. The urban road traffic was composed of light vehicles, heavy vehicles, buses, and powered-two-wheelers in different driving conditions. The tramway traffic corresponded to tramways in in-curve operating configurations. It could be shown that the road traffic and tramway traffic partial annoyance responses were influenced by each other. Throughout the experiments the strongest component effect prevailed but secondary phenomena could also be observed. Considering the perceptual phenomena highlighted in the analysis, it is shown that total noise annoyance due to the combined noises can be most adequately predicted by the strongest component model. This result was obtained by calculating partial annoyance responses due to urban road and tramway traffic.

The influence of traffic signal solutions on self-reported road-crossing behavior.

PubMed

Di Stasi, Leandro L; Megías, Alberto; Cándido, Antonio; Maldonado, Antonio; Catena, Andrés

2015-01-07

Injury to pedestrians is a major safety hazard in many countries. Since the beginning of the last century, modern cities have been designed around the use of motor vehicles despite the unfavourable interactions between the vehicles and pedestrians. This push towards urbanization resulted in a substantial number of crashes and fatalities involving pedestrians every day, all over the world. Thus, improving the design of urban cities and townships is a pressing issue for modern society. The study presented here provides a characterization of pedestrian safety problems, with the emphasis on signalized crosswalks (i.e. traffic signal) design solutions. We tested the impact of seven different traffic light configurations (steady [green, yellow, and red], flashing [green, yellow, and red], and light off) on pedestrian self-reported road-crossing behavior, using a 11-point scale -ranging from 0 ("I never cross in this situation") to 10 ("I always cross in this situation"). Results showed that mandatory solutions (steady green vs. steady red) are the best solutions to avoid unsafe pedestrian behaviors while crossing controlled intersections (frequency of crossing: Mgreen = 9.4 ± 1 vs. Mred = 2.6 ± 2). These findings offer important guidelines for the design of future traffic signals for encouraging a pedestrian/transit-friendly environment.

Assessment of traffic noise levels in urban areas using different soft computing techniques.

PubMed

Tomić, J; Bogojević, N; Pljakić, M; Šumarac-Pavlović, D

2016-10-01

Available traffic noise prediction models are usually based on regression analysis of experimental data, and this paper presents the application of soft computing techniques in traffic noise prediction. Two mathematical models are proposed and their predictions are compared to data collected by traffic noise monitoring in urban areas, as well as to predictions of commonly used traffic noise models. The results show that application of evolutionary algorithms and neural networks may improve process of development, as well as accuracy of traffic noise prediction.

Simulation of traffic control signal systems

NASA Technical Reports Server (NTRS)

Connolly, P. J.; Concannon, P. A.; Ricci, R. C.

1974-01-01

In recent years there has been considerable interest in the development and testing of control strategies for networks of urban traffic signal systems by simulation. Simulation is an inexpensive and timely method for evaluating the effect of these traffic control strategies since traffic phenomena are too complex to be defined by analytical models and since a controlled experiment may be hazardous, expensive, and slow in producing meaningful results. This paper describes the application of an urban traffic corridor program, to evaluate the effectiveness of different traffic control strategies for the Massachusetts Avenue TOPICS Project.

Interspecific comparison of traffic noise effects on dove coo transmission in urban environments.

PubMed

Shieh, Bao-Sen; Liang, Shih-Hsiung; Chiu, Yuh-Wen; Lin, Szu-Ying

2016-08-31

Most previous studies concerning avian adaptation to anthropogenic noise have focused on songbirds, but few have focused on non-songbirds commonly found in urban environments such as doves. We conducted field playback-recording experiments on the perch-coos of five dove species, including four native Taiwan species (the spotted dove, Spilopelia chinensis, the oriental turtle-dove, Streptopelia orientalis, the red collared-dove, Streptopelia tranquebarica, and the emerald dove, Chalcophaps indica) and one species not native to Taiwan (the zebra dove, Geopelia striata) to evaluate the detection and recognition of dove coos in habitats with differing levels of traffic noise. Our results suggest that traffic noise has selected dominant urban species such as the spotted dove to temporally and spatially adjust cooing to reduce the masking effects of traffic noise and rare urban species such as the emerald dove to avoid areas of high traffic noise. Additionally, although the zebra dove had the highest coo frequency among the study species, its coos showed the highest detection value but not the highest recognition value. We conclude that traffic noise is an important factor in shaping the distribution of rare and dominant dove species in urban environments through its significant effects on coo transmission.

Interspecific comparison of traffic noise effects on dove coo transmission in urban environments

NASA Astrophysics Data System (ADS)

Shieh, Bao-Sen; Liang, Shih-Hsiung; Chiu, Yuh-Wen; Lin, Szu-Ying

2016-08-01

Most previous studies concerning avian adaptation to anthropogenic noise have focused on songbirds, but few have focused on non-songbirds commonly found in urban environments such as doves. We conducted field playback-recording experiments on the perch-coos of five dove species, including four native Taiwan species (the spotted dove, Spilopelia chinensis, the oriental turtle-dove, Streptopelia orientalis, the red collared-dove, Streptopelia tranquebarica, and the emerald dove, Chalcophaps indica) and one species not native to Taiwan (the zebra dove, Geopelia striata) to evaluate the detection and recognition of dove coos in habitats with differing levels of traffic noise. Our results suggest that traffic noise has selected dominant urban species such as the spotted dove to temporally and spatially adjust cooing to reduce the masking effects of traffic noise and rare urban species such as the emerald dove to avoid areas of high traffic noise. Additionally, although the zebra dove had the highest coo frequency among the study species, its coos showed the highest detection value but not the highest recognition value. We conclude that traffic noise is an important factor in shaping the distribution of rare and dominant dove species in urban environments through its significant effects on coo transmission.

Study of the air quality in the surroundings of an urban park: A micrometeorological approach

NASA Astrophysics Data System (ADS)

Sastre, Mariano; Yagüe, Carlos; Arrillaga, Jon A.; Román-Cascón, Carlos; Maqueda, Gregorio; Artíñano, Begoña; Díaz-Ramiro, Elías; Gómez-Moreno, Francisco J.; Barreiro, Marcos; Borge, Rafael; Narros, Adolfo; Pérez, Javier; Quaassdorff, Christina

2017-04-01

In this work we study the differences showed by two types of pollutants, particulate matter (PM) and NOx, by comparing ambient concentration measurements within an urban park versus the corresponding values nearby (but outside) it. The results are linked to both proximity to emission sources, such as road traffic, and the microscale atmospheric conditions. The work is motivated by the fact that poor air quality is a crucial issue of current cities. For some of them it is not uncommon to face this problem with occasional traffic restrictions when high concentrations of pollutants are reached. These events occur more frequently with specific large-scale atmospheric conditions, for example when a strong anticyclone is present. As the meteorological conditions may significantly influence the pollutants concentrations, the research project TECNAIRE-CM (Innovative technologies for the assessment and improvement of urban air quality) aims to provide new approaches to obtain proper descriptions of the urban pollution and its dynamics at different spatial and temporal scales, not only the synoptic scale. So far, a few field campaigns have been developed within TECNAIRE-CM at two locations in the city of Madrid, which are considered hot spots according to the air quality network records. Here we use the data from a field campaign carried out during summer 2016, which consider standard pollution and meteorological measurements, as well as sonic anemometer data. The latter help to include atmospheric turbulence as a significant agent for air quality characterization. The instrumentation was deployed at a location with considerable traffic density, but nearby a border of the main urban park of the city, so that its influence might be investigated. Supplementary data considered for this work correspond to permanent instrumentation within the park. With this extra information we can compare both measurements inside and outside the park. Therefore, we study the effect on wind, turbulence or air quality when we measure at a site either directly exposed to traffic emissions or partly protected and with a reduced influence of typical atmospheric urban phenomena. This work has been funded by Madrid Regional Research Plan through TECNAIRE (P2013/MAE-2972).

Environmental impact of electric motorcycles: Evidence from traffic noise assessment by a building-based data mining technique.

PubMed

Sheng, N; Zhou, X; Zhou, Y

2016-06-01

This study provided new evidence on the potential adoption of electric motorcycle (EM) as a cleaner alternative to gasoline-powered motorcycle. The effects of EM on human exposure to traffic noise were assessed in different urban areas with different traffic scenarios. The assessment was carried out by a developed building-based model system that took into account the contribution of motorcycle traffic. The results indicated that the EM could be an appealing solution to reduce the risk of human exposure to excessive high traffic noise in a motorcycle city. Particularly, in a historical urban area in which the total traffic volume was lower and motorcycle traffic was dominant, the proportion of noise levels meeting the standard of 70 dB(A) increased significantly from 12.2% to 41.9% when 100% of gasoline motorcycles in the real traffic scenario were replaced by EMs. On the other hand, in a modern urban area in which the total traffic volume was higher and traffic noise levels at majority of sites were higher than 75 dB(A), the proportion of noise levels above 75 dB(A) decreased significantly from 82.6% to 59.9%. Nevertheless, the effect of EM on improving the traffic noise compliance rate in the modern urban area was not significant and other policies or measures need to be sought. Copyright © 2016 Elsevier B.V. All rights reserved.

Study of annoyance due to urban automobile traffic. Annex 4: A catalog of the characteristics of noise at different measuring points

NASA Technical Reports Server (NTRS)

Aubree, D.; Auzou, S.; Rapin, J. M.

1984-01-01

The characteristics of urban traffic were studied. Data synthesis of and data specifically for the city of Paris concerning noise due to automobile traffic were examined. Information on noise characteristics at different measuring locations is presented.

Robust range estimation with a monocular camera for vision-based forward collision warning system.

PubMed

Park, Ki-Yeong; Hwang, Sun-Young

2014-01-01

We propose a range estimation method for vision-based forward collision warning systems with a monocular camera. To solve the problem of variation of camera pitch angle due to vehicle motion and road inclination, the proposed method estimates virtual horizon from size and position of vehicles in captured image at run-time. The proposed method provides robust results even when road inclination varies continuously on hilly roads or lane markings are not seen on crowded roads. For experiments, a vision-based forward collision warning system has been implemented and the proposed method is evaluated with video clips recorded in highway and urban traffic environments. Virtual horizons estimated by the proposed method are compared with horizons manually identified, and estimated ranges are compared with measured ranges. Experimental results confirm that the proposed method provides robust results both in highway and in urban traffic environments.

Robust Range Estimation with a Monocular Camera for Vision-Based Forward Collision Warning System

PubMed Central

2014-01-01

We propose a range estimation method for vision-based forward collision warning systems with a monocular camera. To solve the problem of variation of camera pitch angle due to vehicle motion and road inclination, the proposed method estimates virtual horizon from size and position of vehicles in captured image at run-time. The proposed method provides robust results even when road inclination varies continuously on hilly roads or lane markings are not seen on crowded roads. For experiments, a vision-based forward collision warning system has been implemented and the proposed method is evaluated with video clips recorded in highway and urban traffic environments. Virtual horizons estimated by the proposed method are compared with horizons manually identified, and estimated ranges are compared with measured ranges. Experimental results confirm that the proposed method provides robust results both in highway and in urban traffic environments. PMID:24558344

Mortality from road traffic accidents in a rapidly urbanizing Chinese city: A 20-year analysis in Shenzhen, 1994-2013.

PubMed

Xie, Shao-Hua; Wu, Yong-Sheng; Liu, Xiao-Jian; Fu, Ying-Bin; Li, Shan-Shan; Ma, Han-Wu; Zou, Fei; Cheng, Jin-Quan

2016-01-01

This study aimed to describe the trends of motorization and mortality rates from road traffic accidents and examine their associations in a rapidly urbanizing city in China, Shenzhen. Using data from the Shenzhen Deaths Registry between 1994 and 2013, we calculated the annual mortality rates of road traffic accidents, in addition to the age- and sex-specific mortality rates and their annual percentage changes (APCs) for the period of 2000-2013. We also examined the associations between mortality rate of road traffic accidents and traffic growth with Spearman's rank correlation analysis and a log-linear model derived from Smeed's law. A total of 20,196 deaths due to road traffic accidents, including 14,391 (71.3%) male deaths and 5,805 (28.7%) female deaths, were recorded in Shenzhen from 1994 to 2013. The annual mortality rates in terms of deaths per population and deaths per vehicle changed in similar patterns, demonstrating an increase since 1994 and peaking in 1997, followed by a steady decrease thereafter. The decrease in mortality was faster in individuals aged 20 year or older compared to those younger than 20 years. The mortality rates in term of deaths per population were positively correlated with the total number of vehicles per kilometer of road but negatively correlated with the motorization rate in term of vehicles per population. The estimated model for deaths due to road traffic accidents in relation to the total population and the number of registered vehicles was ln (deaths/10,000 vehicles) = -1.902 × ln (vehicles/population) - 1.961. The coefficient was statistically significant (P < .001) and the coefficient of determination was 0.966, indicating a good model fit. We described a generally decreasing trend in the mortality rates of road traffic accidents in a rapidly urbanizing Chinese city based observations in the 20-year period from 1994 to 2013. The decreased mortality rate may be explained by the expansion of road network construction, improved road safety regulations and management, as well as more accessible ambulance services in recent years. Nevertheless, road traffic accidents remain a universal problem of great public health concern in the whole population.

Symmetry breaking in optimal timing of traffic signals on an idealized two-way street.

PubMed

Panaggio, Mark J; Ottino-Löffler, Bertand J; Hu, Peiguang; Abrams, Daniel M

2013-09-01

Simple physical models based on fluid mechanics have long been used to understand the flow of vehicular traffic on freeways; analytically tractable models of flow on an urban grid, however, have not been as extensively explored. In an ideal world, traffic signals would be timed such that consecutive lights turned green just as vehicles arrived, eliminating the need to stop at each block. Unfortunately, this "green-wave" scenario is generally unworkable due to frustration imposed by competing demands of traffic moving in different directions. Until now this has typically been resolved by numerical simulation and optimization. Here, we develop a theory for the flow in an idealized system consisting of a long two-way road with periodic intersections. We show that optimal signal timing can be understood analytically and that there are counterintuitive asymmetric solutions to this signal coordination problem. We further explore how these theoretical solutions degrade as traffic conditions vary and automotive density increases.

Symmetry breaking in optimal timing of traffic signals on an idealized two-way street

NASA Astrophysics Data System (ADS)

Panaggio, Mark J.; Ottino-Löffler, Bertand J.; Hu, Peiguang; Abrams, Daniel M.

2013-09-01

Simple physical models based on fluid mechanics have long been used to understand the flow of vehicular traffic on freeways; analytically tractable models of flow on an urban grid, however, have not been as extensively explored. In an ideal world, traffic signals would be timed such that consecutive lights turned green just as vehicles arrived, eliminating the need to stop at each block. Unfortunately, this “green-wave” scenario is generally unworkable due to frustration imposed by competing demands of traffic moving in different directions. Until now this has typically been resolved by numerical simulation and optimization. Here, we develop a theory for the flow in an idealized system consisting of a long two-way road with periodic intersections. We show that optimal signal timing can be understood analytically and that there are counterintuitive asymmetric solutions to this signal coordination problem. We further explore how these theoretical solutions degrade as traffic conditions vary and automotive density increases.

Community structure in traffic zones based on travel demand

NASA Astrophysics Data System (ADS)

Sun, Li; Ling, Ximan; He, Kun; Tan, Qian

2016-09-01

Large structure in complex networks can be studied by dividing it into communities or modules. Urban traffic system is one of the most critical infrastructures. It can be abstracted into a complex network composed of tightly connected groups. Here, we analyze community structure in urban traffic zones based on the community detection method in network science. Spectral algorithm using the eigenvectors of matrices is employed. Our empirical results indicate that the traffic communities are variant with the travel demand distribution, since in the morning the majority of the passengers are traveling from home to work and in the evening they are traveling a contrary direction. Meanwhile, the origin-destination pairs with large number of trips play a significant role in urban traffic network's community division. The layout of traffic community in a city also depends on the residents' trajectories.

Cellular automata model for urban road traffic flow considering pedestrian crossing street

NASA Astrophysics Data System (ADS)

Zhao, Han-Tao; Yang, Shuo; Chen, Xiao-Xu

2016-11-01

In order to analyze the effect of pedestrians' crossing street on vehicle flows, we investigated traffic characteristics of vehicles and pedestrians. Based on that, rules of lane changing, acceleration, deceleration, randomization and update are modified. Then we established two urban two-lane cellular automata models of traffic flow, one of which is about sections with non-signalized crosswalk and the other is on uncontrolled sections with pedestrians crossing street at random. MATLAB is used for numerical simulation of the different traffic conditions; meanwhile space-time diagram and relational graphs of traffic flow parameters are generated and then comparatively analyzed. Simulation results indicate that when vehicle density is lower than around 25 vehs/(km lane), pedestrians have modest impact on traffic flow, whereas when vehicle density is higher than about 60 vehs/(km lane), traffic speed and volume will decrease significantly especially on sections with non-signal-controlled crosswalk. The results illustrate that the proposed models reconstruct the traffic flow's characteristic with the situation where there are pedestrians crossing and can provide some practical reference for urban traffic management.

Prevalence and regional correlates of road traffic injury among Chinese urban residents: A 21-city population-based study.

PubMed

Rockett, Ian R H; Jiang, Shuhan; Yang, Qian; Yang, Tingzhong; Yang, Xiaozhao Y; Peng, Sihui; Yu, Lingwei

2017-08-18

This study estimated the prevalence of road traffic injury among Chinese urban residents and examined individual and regional-level correlates. A cross-sectional multistage process was used to sample residents from 21 selected cities in China. Survey respondents reported their history of road traffic injury in the past 12 months through a community survey. Multilevel, multivariable logistic regression analysis was used to identify injury correlates. Based on a retrospective 12-month reporting window, road traffic injury prevalence among urban residents was 13.2%. Prevalence of road traffic injury, by type, was 8.7, 8.7, 8.5, and 7.7% in the automobile, bicycle, motorcycle, and pedestrian categories, respectively. Multilevel analysis showed that prevalence of road traffic injury was positively associated with minority status, income, and mental health disorder score at the individual level. Regionally, road traffic injury was associated with geographic location of residence and prevalence of mental health disorders. Both individual and regional-level variables were associated with road traffic injury among Chinese urban residents, a finding whose implications transcend wholesale imported generic solutions. This descriptive research demonstrates an urgent need for longitudinal studies across China on risk and protective factors, in order to inform injury etiology, surveillance, prevention, treatment, and evaluation.

Lifestyle as an Influential Factor to Urban Mobility Transport: a Case Study of Semarang City, Indonesia

NASA Astrophysics Data System (ADS)

Ismiyati, I.; Hermawan, F.

2018-02-01

Most of urban spatial structures in developing countries apparently face a typical phenomenon, as well as in Indonesia. The development of the urban spatial structure has the effects, namely to create polycentric pattern (sprawl). Moreover, communication technology believes that the factors of distance and density are highly considered in the organization of the urban structure. In other words, a distance problem is overcome by communication technology, in terms of interaction among people; in running their activities, mobility or distance is not a problem at all. Urban structure as path which is dependent is unable to intervene for an optimum form of urban structure because of dynamic of development objectives. In facts, lifestyle of inhabitant particularly concerning residential and vehicle ownership influences the mobility transport on the tremendous changes in developing countries. On the contrary, this research points out that mobility transport contributes to transportation problems as it becomes increasingly inefficient. Therefore, a sporadic traffic jam and increasing carbon emission issues have risen on the urban phenomenon. It is important to investigate the lifestyle, in terms of residential choice and vehicle ownership to reshape the urban spatial structure. The research aims to draw the urban spatial growth which extends to the phenomenon process toward polycentric pattern and inefficient transport mobility patterns triggering transportation problems in the context of Indonesia. The results confirm that lifestyle regarding residential choices to suburban area and vehicle ownership preference are unable to create the efficient mobility transport, either by cost, density consequences or vehicle ownership as orientation. This research recommends the local authority from multi-disciplinary sector, in particular public policy making to issue permission for authority of land use; residential area and transport agencies for reconciliation with regard to life style aspects in urban spatial planning.

Real-time vehicle emissions monitoring using a compact LiDAR system and conventional instruments: first results of an experimental campaign in a suburban area in southern Italy

NASA Astrophysics Data System (ADS)

Parracino, Stefano; Richetta, Maria; Gelfusa, Michela; Malizia, Andrea; Bellecci, Carlo; De Leo, Leonardo; Perrimezzi, Carlo; Fin, Alessandro; Forin, Marco; Giappicucci, Francesca; Grion, Massimo; Marchese, Giuseppe; Gaudio, Pasquale

2016-10-01

Urban air pollution causes deleterious effects on human health and the environment. To meet stringent standards imposed by the European Commission, advanced measurement methods are required. Remote sensing techniques, such as light detection and ranging (LiDAR), can be a valuable option for evaluating particulate matter (PM), emitted by vehicles in urban traffic, with high sensitivity and in shorter time intervals. Since air quality problems persist not only in large urban areas, a measuring campaign was specifically performed in a suburban area of Crotone, Italy, using both a compact LiDAR system and conventional instruments for real-time vehicle emissions monitoring along a congested road. First results reported in this paper show a strong dependence between variations of LiDAR backscattering signals and traffic-related air pollution levels. Moreover, time-resolved LiDAR data averaged in limited regions, directly above conventional monitoring stations at the border of an intersection, were found to be linearly correlated to the PM concentration levels with a correlation coefficient between 0.75 and 0.84.

Assessment of road traffic noise indices in urban residential areas of Klang Valley, Malaysia

NASA Astrophysics Data System (ADS)

Halim, Herni; Abdullah, Ramdzani; Nor, Mohd Jailani Mohd; Aziz, Hamidi Abdul; Rahman, Noorhazlinda Abd

2017-10-01

Traffic noise has been recognized as a serious threat to the quality of life in most industrialised nations. Klang valley is rapidly emerging as industrialized and urbanized city and has started facing severe noise pollution problems. Urban noise quality assessment is studied in three residential areas; Desa Tun Razak, Kinrara Court and Taman Sentul Utama. Noise pollution indices of L10, L50, L90, Lmax and Lmin as well as equivalent continuous noise level (Leq) were measured for all dwellings. Noise indices results illustrate that Desa Tun Razak recorded the highest values of noise levels among three studied sites. Results also indicate that the highest Leq of 75.7 dB(A) was observed in Desa Tun Razak followed by 74.3 dB(A) in Kinrara Court, and 72.1 dB(A) in Taman Sentul Utama. The noise assessment study clearly reveals the alarming condition of noise pollution in residential areas of Klang Valley as the noise level measured exceeded permissible limit by WHO and Malaysia Guidelines.

A wireless sensor network for urban traffic characterization and trend monitoring.

PubMed

Fernández-Lozano, J J; Martín-Guzmán, Miguel; Martín-Ávila, Juan; García-Cerezo, A

2015-10-15

Sustainable mobility requires a better management of the available infrastructure resources. To achieve this goal, it is necessary to obtain accurate data about road usage, in particular in urban areas. Although a variety of sensor alternates for urban traffic exist, they usually require extensive investments in the form of construction works for installation, processing means, etc. Wireless Sensor Networks (WSN) are an alternative to acquire urban traffic data, allowing for flexible, easy deployment. Together with the use of the appropriate sensors, like Bluetooth identification, and associate processing, WSN can provide the means to obtain in real time data like the origin-destination matrix, a key tool for trend monitoring which previously required weeks or months to be completed. This paper presents a system based on WSN designed to characterize urban traffic, particularly traffic trend monitoring through the calculation of the origin-destination matrix in real time by using Bluetooth identification. Additional sensors are also available integrated in different types of nodes. Experiments in real conditions have been performed, both for separate sensors (Bluetooth, ultrasound and laser), and for the whole system, showing the feasibility of this approach.

The economic cost of road traffic crashes in an urban setting

PubMed Central

García‐Altés, A; Pérez, K

2007-01-01

The objective of this article is to assess the total economic costs of road traffic crashes in Barcelona, a metropolitan city located in Southern Europe. A cost‐of‐illness study was conducted using a prevalence approximation, a societal and healthcare system perspective, and a 1‐year time horizon. Results were measured in terms of Euros in 2003. Total costs of road traffic crashes in Barcelona in 2003 were €367 million. Direct costs equalled €329 million (89.8% of total costs), including property damage costs, insurance administration costs and hospital costs. Police, emergency costs and transportation costs had a minimum effect on total direct costs. Indirect costs were €37 million, including lost productivity due to hospitalization and mortality. The results of the sensitivity analysis showed the upper limit of total economic cost of road traffic crashes in Barcelona to be €782 million. This is the first study to estimate the costs of road traffic crashes for a city in a developed country. The importance of the problem calls for further interventions to reduce road traffic crashes. PMID:17296693

Spatial and temporal variations in traffic-related particulate matter at New York City high schools

NASA Astrophysics Data System (ADS)

Patel, Molini M.; Chillrud, Steven N.; Correa, Juan C.; Feinberg, Marian; Hazi, Yair; Deepti, K. C.; Prakash, Swati; Ross, James M.; Levy, Diane; Kinney, Patrick L.

Relatively little is known about exposures to traffic-related particulate matter at schools located in dense urban areas. The purpose of this study was to examine the influences of diesel traffic proximity and intensity on ambient concentrations of fine particulate matter (PM 2.5) and black carbon (BC), an indicator of diesel exhaust particles, at New York City (NYC) high schools. Outdoor PM 2.5 and BC were monitored continuously for 4-6 weeks at each of 3 NYC schools and 1 suburban school located 40 km upwind of the city. Traffic count data were obtained using an automated traffic counter or video camera. BC concentrations were 2-3 fold higher at urban schools compared with the suburban school, and among the 3 urban schools, BC concentrations were higher at schools located adjacent to highways. PM 2.5 concentrations were significantly higher at urban schools than at the suburban school, but concentrations did not vary significantly among urban schools. Both hourly average counts of trucks and buses and meteorological factors such as wind direction, wind speed, and humidity were significantly associated with hourly average ambient BC and PM 2.5 concentrations in multivariate regression models. An increase of 443 trucks/buses per hour was associated with a 0.62 μg/m 3 increase in hourly average BC at an NYC school located adjacent to a major interstate highway. Car traffic counts were not associated with BC. The results suggest that local diesel vehicle traffic may be important sources of airborne fine particles in dense urban areas and consequently may contribute to local variations in PM 2.5 concentrations. In urban areas with higher levels of diesel traffic, local, neighborhood-scale monitoring of pollutants such as BC, which compared to PM 2.5, is a more specific indicator of diesel exhaust particles, may more accurately represent population exposures.

Ultrasonic Sensors in Urban Traffic Driving-Aid Systems

PubMed Central

Alonso, Luciano; Milanés, Vicente; Torre-Ferrero, Carlos; Godoy, Jorge; Oria, Juan P.; de Pedro, Teresa

2011-01-01

Currently, vehicles are often equipped with active safety systems to reduce the risk of accidents, most of which occur in urban environments. The most prominent include Antilock Braking Systems (ABS), Traction Control and Stability Control. All these systems use different kinds of sensors to constantly monitor the conditions of the vehicle, and act in an emergency. In this paper the use of ultrasonic sensors in active safety systems for urban traffic is proposed, and the advantages and disadvantages when compared to other sensors are discussed. Adaptive Cruise Control (ACC) for urban traffic based on ultrasounds is presented as an application example. The proposed system has been implemented in a fully-automated prototype vehicle and has been tested under real traffic conditions. The results confirm the good performance of ultrasonic sensors in these systems. PMID:22346596

Ultrasonic sensors in urban traffic driving-aid systems.

PubMed

Alonso, Luciano; Milanés, Vicente; Torre-Ferrero, Carlos; Godoy, Jorge; Oria, Juan P; de Pedro, Teresa

2011-01-01

Currently, vehicles are often equipped with active safety systems to reduce the risk of accidents, most of which occur in urban environments. The most prominent include Antilock Braking Systems (ABS), Traction Control and Stability Control. All these systems use different kinds of sensors to constantly monitor the conditions of the vehicle, and act in an emergency. In this paper the use of ultrasonic sensors in active safety systems for urban traffic is proposed, and the advantages and disadvantages when compared to other sensors are discussed. Adaptive Cruise Control (ACC) for urban traffic based on ultrasounds is presented as an application example. The proposed system has been implemented in a fully-automated prototype vehicle and has been tested under real traffic conditions. The results confirm the good performance of ultrasonic sensors in these systems.

Using recorded sound spectra profile as input data for real-time short-term urban road-traffic-flow estimation.

PubMed

Torija, Antonio J; Ruiz, Diego P

2012-10-01

Road traffic has a heavy impact on the urban sound environment, constituting the main source of noise and widely dominating its spectral composition. In this context, our research investigates the use of recorded sound spectra as input data for the development of real-time short-term road traffic flow estimation models. For this, a series of models based on the use of Multilayer Perceptron Neural Networks, multiple linear regression, and the Fisher linear discriminant were implemented to estimate road traffic flow as well as to classify it according to the composition of heavy vehicles and motorcycles/mopeds. In view of the results, the use of the 50-400 Hz and 1-2.5 kHz frequency ranges as input variables in multilayer perceptron-based models successfully estimated urban road traffic flow with an average percentage of explained variance equal to 86%, while the classification of the urban road traffic flow gave an average success rate of 96.1%. Copyright © 2012 Elsevier B.V. All rights reserved.

Impact on air quality of measures to reduce CO2 emissions from road traffic in Basel, Rotterdam, Xi'an and Suzhou

NASA Astrophysics Data System (ADS)

Keuken, M. P.; Jonkers, S.; Verhagen, H. L. M.; Perez, L.; Trüeb, S.; Okkerse, W.-J.; Liu, J.; Pan, X. C.; Zheng, L.; Wang, H.; Xu, R.; Sabel, C. E.

2014-12-01

Two traffic scenarios to reduce CO2 emissions from road traffic in two European cities (Basel and Rotterdam) and two Chinese cities (Xi'an and Suzhou) were evaluated in terms of their impact on air quality. The two scenarios, one modelling a reduction of private vehicle kilometres driven by 10% on urban streets and the other modelling the introduction of 50% electric-powered private vehicle kilometres on urban streets, were both compared to a scenario following “business-as-usual”: 2020-BAU. The annual average concentrations of NO2, PM2.5, PM10 and elemental carbon (EC) were modelled separately in busy street canyons, near urban motorways and in the remainder of the urban area. It was concluded that traffic-related CO2 emissions in 2020-BAU could be expected to remain at the levels of 2010 in Basel and Rotterdam, while in Xi'an and Suzhou to increase 30-50% due to growth in the traffic volume. Traffic-related CO2 emissions may be reduced by up to 5% and 25%, respectively using the first and second scenarios. Air pollution in the Chinese cities is a factor 3 to 5 higher than in the European cities in 2010 and 2020-BAU. The impact of both CO2 reduction scenarios on air quality in 2020-BAU is limited. In Europe, due to implementation of stringent emission standards in all sectors, air quality is expected to improve at both the urban background and near busy road traffic. In China, the regional background is expected to improve for EC, stabilize for PM2.5 and PM10, and decrease for NO2. The urban background follows this regional trend, while near busy road traffic, air pollution will remain elevated due to the considerable growth in traffic volume. A major constraint for modelling air quality in China is access to the input data required and lack of measurements at ground level for validation.

Modeling carbon emissions from urban traffic system using mobile monitoring.

PubMed

Sun, Daniel Jian; Zhang, Ying; Xue, Rui; Zhang, Yi

2017-12-01

Comprehensive analyses of urban traffic carbon emissions are critical in achieving low-carbon transportation. This paper started from the architecture design of a carbon emission mobile monitoring system using multiple sets of equipment and collected the corresponding data about traffic flow, meteorological conditions, vehicular carbon emissions and driving characteristics on typical roads in Shanghai and Wuxi, Jiangsu province. Based on these data, the emission model MOVES was calibrated and used with various sensitivity and correlation evaluation indices to analyze the traffic carbon emissions at microscopic, mesoscopic and macroscopic levels, respectively. The major factors that influence urban traffic carbon emissions were investigated, so that emission factors of CO, CO 2 and HC were calculated by taking representative passenger cars as a case study. As a result, the urban traffic carbon emissions were assessed quantitatively, and the total amounts of CO, CO 2 and HC emission from passenger cars in Shanghai were estimated as 76.95kt, 8271.91kt, and 2.13kt, respectively. Arterial roads were found as the primary line source, accounting for 50.49% carbon emissions. In additional to the overall major factors identified, the mobile monitoring system and carbon emission quantification method proposed in this study are of rather guiding significance for the further urban low-carbon transportation development. Copyright © 2017 Elsevier B.V. All rights reserved.

Discovering urban mobility patterns with PageRank based traffic modeling and prediction

NASA Astrophysics Data System (ADS)

Wang, Minjie; Yang, Su; Sun, Yi; Gao, Jun

2017-11-01

Urban transportation system can be viewed as complex network with time-varying traffic flows as links to connect adjacent regions as networked nodes. By computing urban traffic evolution on such temporal complex network with PageRank, it is found that for most regions, there exists a linear relation between the traffic congestion measure at present time and the PageRank value of the last time. Since the PageRank measure of a region does result from the mutual interactions of the whole network, it implies that the traffic state of a local region does not evolve independently but is affected by the evolution of the whole network. As a result, the PageRank values can act as signatures in predicting upcoming traffic congestions. We observe the aforementioned laws experimentally based on the trajectory data of 12000 taxies in Beijing city for one month.

Urban snow indicates pollution originating from road traffic.

PubMed

Kuoppamäki, Kirsi; Setälä, Heikki; Rantalainen, Anna-Lea; Kotze, D Johan

2014-12-01

Traffic is a major source of pollutants in cities. In this well-replicated study we analysed a broad array of contaminants in snowpacks along roads of different traffic intensities. The majority of pollutants showed a similar pattern with respect to traffic intensity: pH and conductivity as well as concentrations of PAHs, total suspended solids, phosphorus and most heavy metals were higher next to high intensity roads compared to low intensity roads. These pollutant levels also decreased considerably up to 5 m distance from the roads. Furthermore, apart from nitrogen, these variables increased in concentration from control sites in urban forest patches to road bank sites next to roads of low, intermediate and high traffic intensities. The deposition pattern of various traffic-derived pollutants--whether gaseous or particle-bound--was the same. Such information can be useful for the purposes of managing pollutants in urban areas. Copyright © 2014 Elsevier Ltd. All rights reserved.

Urban trees and traffic safety: considering the U.S. roadside policy and crash data

Treesearch

Kathleen L. Wolf

2006-01-01

In the mid to late 20th century, U.S. transportation agencies focused on traffic planning and design practices intended to achieve high levels of traffic capacity and safety for roads at lowest cost. Intangible values of the roadside such as community character and environmental systems were often overlooked, including the urban forest....

Research on Influence and Prediction Model of Urban Traffic Link Tunnel curvature on Fire Temperature Based on Pyrosim--SPSS Multiple Regression Analysis

NASA Astrophysics Data System (ADS)

Li, Xiao Ju; Yao, Kun; Dai, Jun Yu; Song, Yun Long

2018-05-01

The underground space, also known as the “fourth dimension” of the city, reflects the efficient use of urban development intensive. Urban traffic link tunnel is a typical underground limited-length space. Due to the geographical location, the special structure of space and the curvature of the tunnel, high-temperature smoke can easily form the phenomenon of “smoke turning” and the fire risk is extremely high. This paper takes an urban traffic link tunnel as an example to focus on the relationship between curvature and the temperature near the fire source, and use the pyrosim built different curvature fire model to analyze the influence of curvature on the temperature of the fire, then using SPSS Multivariate regression analysis simulate curvature of the tunnel and fire temperature data. Finally, a prediction model of urban traffic link tunnel curvature on fire temperature was proposed. The regression model analysis and test show that the curvature is negatively correlated with the tunnel temperature. This model is feasible and can provide a theoretical reference for the urban traffic link tunnel fire protection design and the preparation of the evacuation plan. And also, it provides some reference for other related curved tunnel curvature design and smoke control measures.

[Analysis of the death cases in the urban rail traffic accident in Shanghai].

PubMed

Hu, Yi-Ping; Cao, Yu; Ma, Kai-Jun

2009-06-01

To analyze the features of death cases in the urban rail traffic accidents in order to prevent the similar accidents in the future and to provide reference for forensic expertise. Eighteen death cases in urban rail traffic accidents between 2005 to 2008 in Shanghai were collected. The forensic characteristics were summarized in aspects of the nature of cases, the injury mechanism and characteristics, etc. There were total 18 cases with 14 suicide and 4 accidental incidents, aged from 21 to 55 years. Of those dead, 14 died of craniocerebral injury and 4 died of traumatic shock. The injury mechanism included hit, fall and rolling. The injury in urban rail traffic accidents have their own characteristics, mainly due to suicide, and partly due to accidental incident, and most of these cases are probably preventable.

Analysis of the build-up of semi and non volatile organic compounds on urban roads.

PubMed

Mahbub, Parvez; Ayoko, Godwin A; Goonetilleke, Ashantha; Egodawatta, Prasanna

2011-04-01

Vehicular traffic in urban areas may adversely affect urban water quality through the build-up of traffic generated semi and non volatile organic compounds (SVOCs and NVOCs) on road surfaces. The characterisation of the build-up processes is the key to developing mitigation measures for the removal of such pollutants from urban stormwater. An in-depth analysis of the build-up of SVOCs and NVOCs was undertaken in the Gold Coast region in Australia. Principal Component Analysis (PCA) and Multicriteria Decision tools such as PROMETHEE and GAIA were employed to understand the SVOC and NVOC build-up under combined traffic scenarios of low, moderate, and high traffic in different land uses. It was found that congestion in the commercial areas and use of lubricants and motor oils in the industrial areas were the main sources of SVOCs and NVOCs on urban roads, respectively. The contribution from residential areas to the build-up of such pollutants was hardly noticeable. It was also revealed through this investigation that the target SVOCs and NVOCs were mainly attached to particulate fractions of 75-300 μm whilst the redistribution of coarse fractions due to vehicle activity mainly occurred in the >300 μm size range. Lastly, under combined traffic scenario, moderate traffic with average daily traffic ranging from 2300 to 5900 and average congestion of 0.47 were found to dominate SVOC and NVOC build-up on roads. Copyright © 2011 Elsevier Ltd. All rights reserved.

Residents' evaluation of urban environments: attraction of urban life and anxiety associated with traffic accidents and urban crimes.

PubMed

Tachikawa, Tomoko; Hashimoto, Shusa

2007-12-01

The results of questionnaire and interview surveys conducted in Mitaka and Musashino cities are presented for investigating of residents' evaluation of their urban environment, particularly regarding its attractiveness. A special attention was paid to residents' evaluation with regard to anxiety associated with traffic accidents and urban crimes. The urban infrastructure and residents' responses were examined using a Geographic Information System (GIS). Attractiveness associated with the urban environment was classified into two categories: "attractiveness in daily life" and "attractiveness in non-daily life." The residents valued opportunities for relaxing and living in comfort. In non-daily life, the residents specifically valued improved living conditions and harmony between the natural environment and commercial facilities. They attributed crime anxiety to trees, narrow streets, obstructed views, dark areas and a gloomy atmosphere. Residents regarded violent crimes as being prevalent, but considered trespassing and property crimes infrequent. The residents' anxiety about traffic accidents was caused by reckless driving habits, narrow streets, lack of separation between roadway and pedestrians' ways, heavy traffic, and obstructed views. Residents cited main roads and intersections as locations of anxiety, which concurred with frequent accidents.

A Wireless Sensor Network for Urban Traffic Characterization and Trend Monitoring

PubMed Central

Fernández-Lozano, J.J.; Martín-Guzmán, Miguel; Martín-Ávila, Juan; García-Cerezo, A.

2015-01-01

Sustainable mobility requires a better management of the available infrastructure resources. To achieve this goal, it is necessary to obtain accurate data about road usage, in particular in urban areas. Although a variety of sensor alternates for urban traffic exist, they usually require extensive investments in the form of construction works for installation, processing means, etc. Wireless Sensor Networks (WSN) are an alternative to acquire urban traffic data, allowing for flexible, easy deployment. Together with the use of the appropriate sensors, like Bluetooth identification, and associate processing, WSN can provide the means to obtain in real time data like the origin-destination matrix, a key tool for trend monitoring which previously required weeks or months to be completed. This paper presents a system based on WSN designed to characterize urban traffic, particularly traffic trend monitoring through the calculation of the origin-destination matrix in real time by using Bluetooth identification. Additional sensors are also available integrated in different types of nodes. Experiments in real conditions have been performed, both for separate sensors (Bluetooth, ultrasound and laser), and for the whole system, showing the feasibility of this approach. PMID:26501278

Optimizing Energy Consumption in Vehicular Sensor Networks by Clustering Using Fuzzy C-Means and Fuzzy Subtractive Algorithms

NASA Astrophysics Data System (ADS)

Ebrahimi, A.; Pahlavani, P.; Masoumi, Z.

2017-09-01

Traffic monitoring and managing in urban intelligent transportation systems (ITS) can be carried out based on vehicular sensor networks. In a vehicular sensor network, vehicles equipped with sensors such as GPS, can act as mobile sensors for sensing the urban traffic and sending the reports to a traffic monitoring center (TMC) for traffic estimation. The energy consumption by the sensor nodes is a main problem in the wireless sensor networks (WSNs); moreover, it is the most important feature in designing these networks. Clustering the sensor nodes is considered as an effective solution to reduce the energy consumption of WSNs. Each cluster should have a Cluster Head (CH), and a number of nodes located within its supervision area. The cluster heads are responsible for gathering and aggregating the information of clusters. Then, it transmits the information to the data collection center. Hence, the use of clustering decreases the volume of transmitting information, and, consequently, reduces the energy consumption of network. In this paper, Fuzzy C-Means (FCM) and Fuzzy Subtractive algorithms are employed to cluster sensors and investigate their performance on the energy consumption of sensors. It can be seen that the FCM algorithm and Fuzzy Subtractive have been reduced energy consumption of vehicle sensors up to 90.68% and 92.18%, respectively. Comparing the performance of the algorithms implies the 1.5 percent improvement in Fuzzy Subtractive algorithm in comparison.

The impact of traffic emissions on air quality in the Berlin-Brandenburg region - a case study on cycling scenarios

NASA Astrophysics Data System (ADS)

Kuik, F.; Lauer, A.; von Schneidemesser, E.; Butler, T. M.

2016-12-01

Many European cities continue to struggle with exceedances of NO2 limit values at measurement sites near roads, of which a large contribution is attributed to emissions from traffic. In this study, we explore how urban air quality can be improved with different traffic measures using the example of the Berlin-Brandenburg region. In order to simulate urban background air quality we use the Weather Research and Forecasting model with chemistry (WRF-Chem) at a horizontal resolution of 1km. We use emission input data at a horizontal resolution of 1km obtained by downscaling TNO-MACC III emissions based on local proxy data including population and traffic densities. In addition we use a statistical approach combining the simulated urban background concentrations with information on traffic densities to estimate NO2 at street level. This helps assessing whether the emission scenarios studied here can lead to significant reductions in NO2 concentrations at street level. The emission scenarios in this study represent a range of scenarios in which car traffic is replaced with bicycle traffic. Part of this study was an initial discussion phase with stakeholders, including policy makers and NGOs. The discussions have shown that the different stakeholders are interested in a scientific assessment of the impact of replacing car traffic with bicycle traffic in the Berlin-Brandenburg urban area. Local policy makers responsible for city planning and implementing traffic measures can make best use of scientific modeling results if input data and scenarios are as realistic as possible. For these reasons, the scenarios cover very idealized optimistic ("all passenger cars are replaced by bicycles") and pessimistic ("all cyclists are replaced by cars") scenarios to explore the sensitivity of simulated urban background air quality to these changes, as well as additional scenarios based on city-specific data to analyze more realistic situations. Of particular interest is how these impact street level NO2 concentrations.

Evidence of Long Range Dependence and Self-similarity in Urban Traffic Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thakur, Gautam S; Helmy, Ahmed; Hui, Pan

2015-01-01

Transportation simulation technologies should accurately model traffic demand, distribution, and assignment parame- ters for urban environment simulation. These three param- eters significantly impact transportation engineering bench- mark process, are also critical in realizing realistic traffic modeling situations. In this paper, we model and charac- terize traffic density distribution of thousands of locations around the world. The traffic densities are generated from millions of images collected over several years and processed using computer vision techniques. The resulting traffic den- sity distribution time series are then analyzed. It is found using the goodness-of-fit test that the traffic density dis- tributions follows heavy-tailmore » models such as Log-gamma, Log-logistic, and Weibull in over 90% of analyzed locations. Moreover, a heavy-tail gives rise to long-range dependence and self-similarity, which we studied by estimating the Hurst exponent (H). Our analysis based on seven different Hurst estimators strongly indicate that the traffic distribution pat- terns are stochastically self-similar (0.5 H 1.0). We believe this is an important finding that will influence the design and development of the next generation traffic simu- lation techniques and also aid in accurately modeling traffic engineering of urban systems. In addition, it shall provide a much needed input for the development of smart cities.« less

Evaluation of daily time spent in transportation and traffic-influenced microenvironments by urban Canadians.

PubMed

Matz, Carlyn J; Stieb, David M; Egyed, Marika; Brion, Orly; Johnson, Markey

2018-01-01

Exposure to traffic and traffic-related air pollution is associated with a wide array of health effects. Time spent in a vehicle, in active transportation, along roadsides, and in close proximity to traffic can substantially contribute to daily exposure to air pollutants. For this study, we evaluated daily time spent in transportation and traffic-influenced microenvironments by urban Canadians using the Canadian Human Activity Pattern Survey (CHAPS) 2 results. Approximately 4-7% of daily time was spent in on- or near-road locations, mainly associated with being in a vehicle and smaller contributions from active transportation. Indoor microenvironments can be impacted by traffic emissions, especially when located near major roadways. Over 60% of the target population reported living within one block of a roadway with moderate to heavy traffic, which was variable with income level and city, and confirmed based on elevated NO 2 exposure estimated using land use regression. Furthermore, over 55% of the target population ≤ 18 years reported attending a school or daycare in close proximity to moderate to heavy traffic, and little variation was observed based on income or city. The results underline the importance of traffic emissions as a major source of exposure in Canadian urban centers, given the time spent in traffic-influenced microenvironments.

Hourly elemental concentrations in PM2.5 aerosols sampled simultaneously at urban background and road site

NASA Astrophysics Data System (ADS)

Dall'Osto, M.; Querol, X.; Amato, F.; Karanasiou, A.; Lucarelli, F.; Nava, S.; Calzolai, G.; Chiari, M.

2012-08-01

Hourly-resolved aerosol chemical speciation data can be a highly powerful tool to determine the source origin of atmospheric pollutants in urban Environments. Aerosol mass concentrations of seventeen elements (Na, Mg, Al, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Sr and Pb) were obtained by time (1 h) and size (PM2.5 particulate matter <2.5 μm) resolved Particle Induced X-ray Emission (PIXE) measurements. In the Marie Curie FP7-EU framework of SAPUSS (Solving Aerosol Problems by Using Synergistic Strategies), the unique approach used is the simultaneous PIXE measurements at two monitoring sites: urban background (UB) and a street canyon traffic road site (RS). Elements related to primary non exhaust traffic emission (Fe, Cu), dust resuspension (Ca) and anthropogenic Cl were found enhanced at the RS, whereas industrial related trace metals (Zn, Pb, Mn) were found at higher concentrations at the more ventilated UB site. When receptor modelling was performed with positive matrix factorization (PMF), nine different aerosol sources were identified at both sites: three types of regional aerosols (secondary sulphate (S) - 27%, biomass burning (K) - 5%, sea salt (Na-Mg) - 17%), three types of dust aerosols (soil dust (Al-Ti) - 17%, urban crustal dust (Ca) - 6%, and primary traffic non exhaust brake dust (Fe-Cu) - 7%), and three types industrial aerosol plumes-like events (shipping oil combustion (V-Ni) - 17%, industrial smelters (Zn-Mn) - 3%, and industrial combustion (Pb-Cl) - 5%). The validity of the PMF solution of the PIXE data is supported by strong correlations with external single particle mass spectrometry measurements. Beside apportioning the aerosol sources, some important air quality related conclusions can be drawn about the PM2.5 fraction simultaneously measured at the UB and RS sites: (1) the regional aerosol sources impact both monitoring sites at similar concentrations regardless their different ventilation conditions; (2) by contrast, local industrial aerosol plumes associated with shipping oil combustion and smelters activities have a higher impact on the more ventilated UB site; (3) a unique source of Pb-Cl (associated with industrial combustion emissions) is found a to be the major (82%) source of Cl in the urban agglomerate; (4) PM2.5 traffic brake dust (Fe-Cu) is mainly primarily emitted and not resuspended, whereas PM2.5 urban crustal dust (Ca) is found mainly resuspended by both traffic vortex and sea breeze; (5) urban dust (Ca) is found the aerosol source most affected by land wetness, reduced by a factor of eight during rainy days and suggesting that wet roads may be a solution for reducing dust concentrations in road sites, far more effective than street sweeping activities.

What Have we Learned about Intelligent Transportation Systems?

DOT National Transportation Integrated Search

1980-01-01

The Traffic Planning manual is a reference of basic traffic enginnering techniques and their potential for improving traffic flow and traffic safety of urban arterial streets and highways. The manual identifies the traffic engineering measure appropr...

Appalachian versus non-Appalachian US traffic fatalities, 2008-2010

PubMed Central

Zhu, Motao; Zhao, Songzhu; Gurka, Kelly K.; Kandati, Sahiti; Coben, Jeffrey H.

2013-01-01

Purpose Though myriad health disparities exist in Appalachia, limited research has examined traffic fatalities in the region. This study compared traffic-fatality rates in Appalachia and the non-Appalachian US. Methods Fatality Analysis Reporting System and Census data from 2008-2010 were used to calculate traffic-fatality rates. Poisson models were used to estimate unadjusted (RR) and adjusted rate ratios (aRR), controlling for age, sex, and county-specific population density levels. Results: The Appalachian traffic-fatality rate was 45% (95% CI: 1.42, 1.47) higher than the non-Appalachian rate. Though only 29% of fatalities occur in rural counties in non-Appalachia versus 48% in Appalachia, rates in rural counties were similar (RR=0.97; 95% CI: 0.95, 1.00). However, the rate for urban, Appalachian counties was 42% (95% CI: 1.38, 1.45) higher than among urban, non-Appalachian counties. Appalachian rates were higher for passenger-vehicle drivers, motorcyclists, and all-terrain-vehicle riders, regardless of rurality, as well as for passenger-vehicle passengers overall and for urban counties. Conversely, Appalachia experienced lower rates among pedestrians and bicyclists, regardless of rurality. Conclusions Disparities in traffic fatality rates exist in Appalachia. Though elevated rates are partially explained by the proportion of residents living in rural settings, overall rates in urban Appalachia were consistently higher than in urban non-Appalachia. PMID:23619016

Impacts of Roadway Emissions on Urban Fine Particle Exposures: the Nairobi Area Traffic Contribution to Air Pollution (NATCAP) Study

NASA Astrophysics Data System (ADS)

Gatari, Michael; Ngo, Nicole; Ndiba, Peter; Kinney, Patrick

2010-05-01

Air quality is a serious and worsening problem in the rapidly growing cities of sub-Saharan Africa (SSA), due to rapid urbanization, growing vehicle fleets, changing life styles, limited road infrastructure and land use planning, and high per-vehicle emissions. However, the absence of ambient monitoring data, and particularly urban roadside concentrations of particulate matter in SSA cities, severely limits our ability to assess the real extent of air quality problems. Emitted fine particles by on-road vehicles may be particularly important in SSA cities because large concentrations of poorly maintained vehicles operate in close proximity to commercial and other activities of low-income urban residents. This scenario provokes major air quality concerns and its investigation should be of priority interest to policy makers, city planners and managers, and the affected population. As part of collaboration between Columbia University and the University of Nairobi, a PM2.5 air monitoring study was carried out over two weeks in July 2009. The objectives of the study were 1) to assess average daytime PM2.5 concentrations on a range of Nairobi streets that represent important hot-spots in terms of the joint distribution of traffic, commercial, and resident pedestrian activities, 2) to relate those concentrations to motor vehicle counts, 3) to compare urban street concentrations to urban and rural background levels, and 4) to assess vertical and horizontal dispersion of PM2.5 near roadways. Portable, battery-operated PM2.5 samplers were carried by field teams at each of the five sites (three urban, one commuter highway, and one rural site), each of which operated from 7 AM to 7 PM during 10 weekdays in July 2009. Urban background monitoring took place on a rooftop at the University of Nairobi. Preliminary findings suggest highly elevated PM2.5 concentrations at the urban sites where the greatest pedestrian traffic was observed. These findings underscore the need for air quality and transportation planning and management directed at mitigating roadway pollution. Reducing PM emissions from motor vehicles would have direct health benefits for residents of Nairobi and other SSA cities. However, further studies are required to depict the seasonal variations, include gaseous pollution aspect, and strengthen the knowledge on air quality in the region as well as improving the data base for health impact assessment. Acknowledgement This study was initiated and funded by Columbia University's Earth Institute's Center for Sustainable Urban Development (CSUD). CSUD is a Volvo Research and Educational Foundations Center of Excellence for Future Urban Transport. International Science Programs (ISP), Uppsala University, Sweden is recognized for its research support to Institute of Nuclear Science & Technology. Additional technical support for air monitoring and analysis was provided by the Exposure Assessment Facility Core of the Center for Environmental Health in Northern Manhattan (NIEHS P30 ES09089).

Michigan urban trunkline segments safety performance functions (SPFs) : final report.

DOT National Transportation Integrated Search

2016-07-01

This study involves the development of safety performance functions (SPFs) for urban and suburban trunkline segments in the : state of Michigan. Extensive databases were developed through the integration of traffic crash information, traffic volumes,...

On the spatial distribution and evolution of ultrafine particles in Barcelona

NASA Astrophysics Data System (ADS)

Dall'Osto, M.; Querol, X.; Alastuey, A.; O'Dowd, C.; Harrison, R. M.; Wenger, J.; Gómez-Moreno, F. J.

2013-01-01

Sources and evolution of ultrafine particles were investigated both horizontally and vertically in the large urban agglomerate of Barcelona, Spain. Within the SAPUSS project (Solving Aerosol Problems by Using Synergistic Strategies), a large number of instruments was deployed simultaneously at different monitoring sites (road, two urban background, regional background, urban tower 150 m a.s.l., urban background tower site 80 m a.s.l.) during a 4 week period in September-October 2010. Particle number concentrations (N>5 nm) are highly correlated with black carbon (BC) at all sites only under strong vehicular traffic influences. By contrast, under cleaner atmospheric conditions (low condensation sink, CS) such correlation diverges towards much higher N/BC ratios at all sites, indicating additional sources of particles including secondary production of freshly nucleated particles. Size-resolved aerosol distributions (N10-500) as well as particle number concentrations (N>5 nm) allow us to identify three types of nucleation and growth events: (1) a regional type event originating in the whole study region and impacting almost simultaneously the urban city of Barcelona and the surrounding urban background area; (2) a regional type event impacting only the regional background area but not the urban agglomerate; (3) an urban type event which originates only within the city centre but whose growth continues while transported away from the city to the regional background. Furthermore, during these clean air days, higher N are found at tower level than at ground level only in the city centre whereas such a difference is not so pronounced at the remote urban background tower. In other words, this study suggests that the column of air above the city ground level possesses the optimal combination between low CS and high vapour source, hence enhancing the concentrations of freshly nucleated particles. By contrast, within stagnant polluted atmospheric conditions, higher N and BC concentrations are always measured at ground level relative to tower level at all sites. Our study suggests that the city centre of Barcelona is a source of non-volatile traffic primary particles (29-39% of N>5 nm), but other sources, including secondary freshly nucleated particles contribute up to 61-71% of particle number (N>5 nm) at all sites. We suggest that organic compounds evaporating from freshly emitted traffic particles are a possible candidate for new particle formation within the city and urban plume.

On the spatial distribution and evolution of ultrafine aerosols in urban air

NASA Astrophysics Data System (ADS)

Dall'Osto, M.; Querol, X.; Alastuey, A.; O'Dowd, C.; Harrison, R. M.; Wenger, J.; Gómez-Moreno, F. J.

2012-07-01

Sources and evolution of ultrafine particles (<0.1 μ m diameter) were investigated both horizontally and vertically in the large urban agglomerate of Barcelona, Spain. Within the SAPUSS project (Solving Aerosol Problems by Using Synergistic Strategies), a large number of instruments was deployed simultaneously at different monitoring sites (road, two urban background, regional background, urban tower 150 μa.s.l., urban background tower site 80 m a.s.l.) during a 4 week period in September-October 2010. Particle number concentrations (N>5nm) are highly correlated with black carbon (BC) at all sites only under strong vehicular traffic influences. By contrast, under clean atmospheric conditions (low condensation sinks, CS) such correlation diverges towards much higher N/BC ratios at all sites, indicating additional sources of particles including secondary production of freshly nucleated particles. This is also evident in the urban background annual mean diurnal trend of N/BC, showing a midday peak in all seasons. Size-resolved aerosol distributions (N10-500) as well as particle number concentrations (N>5nm) allow us to identify two types of nucleation and growth events: a regional type event originating in the whole study region and impacting almost simultaneously the urban city of Barcelona and the surrounding background area; and an urban type which originates only within the city centre but whose growth continues while transported away from the city to the regional background. Furthermore, during these clean air days, higher N are found at tower level than at ground level only in the city centre whereas such a difference is not so pronounced at the remote urban background tower. In other words, this study suggests that the column of air above the city ground level possesses the best compromise between low CS and high vapour source, hence enhancing the concentrations of freshly nucleated particles. By contrast, within stagnant polluted atmospheric conditions, higher N and BC concentrations are always measured at ground level relative to tower level at all sites. Our study suggests that the city centre is a source of both non-volatile traffic primary (29-39%) and secondary freshly nucleated particles (up to 61-71%) at all sites. We suggest that organic compounds evaporating from freshly emitted traffic particles are a possible candidate for new particle formation within the city and urban plume.

Variable speed limit strategies analysis with link transmission model on urban expressway

NASA Astrophysics Data System (ADS)

Li, Shubin; Cao, Danni

2018-02-01

The variable speed limit (VSL) is a kind of active traffic management method. Most of the strategies are used in the expressway traffic flow control in order to ensure traffic safety. However, the urban expressway system is the main artery, carrying most traffic pressure. It has similar traffic characteristics with the expressways between cities. In this paper, the improved link transmission model (LTM) combined with VSL strategies is proposed, based on the urban expressway network. The model can simulate the movement of the vehicles and the shock wave, and well balance the relationship between the amount of calculation and accuracy. Furthermore, the optimal VSL strategy can be proposed based on the simulation method. It can provide management strategies for managers. Finally, a simple example is given to illustrate the model and method. The selected indexes are the average density, the average speed and the average flow on the traffic network in the simulation. The simulation results show that the proposed model and method are feasible. The VSL strategy can effectively alleviate traffic congestion in some cases, and greatly promote the efficiency of the transportation system.

Effects of iterative learning based signal control strategies on macroscopic fundamental diagrams of urban road networks

NASA Astrophysics Data System (ADS)

Yan, Fei; Tian, Fuli; Shi, Zhongke

2016-10-01

Urban traffic flows are inherently repeated on a daily or weekly basis. This repeatability can help improve the traffic conditions if it is used properly by the control system. In this paper, we propose a novel iterative learning control (ILC) strategy for traffic signals of urban road networks using the repeatability feature of traffic flow. To improve the control robustness, the ILC strategy is further integrated with an error feedback control law in a complementary manner. Theoretical analysis indicates that the ILC-based traffic signal control methods can guarantee the asymptotic learning convergence, despite the presence of modeling uncertainties and exogenous disturbances. Finally, the impacts of the ILC-based signal control strategies on the network macroscopic fundamental diagram (MFD) are examined. The results show that the proposed ILC-based control strategies can homogenously distribute the network accumulation by controlling the vehicle numbers in each link to the desired levels under different traffic demands, which can result in the network with high capacity and mobility.

The impact of traffic-flow patterns on air quality in urban street canyons.

PubMed

Thaker, Prashant; Gokhale, Sharad

2016-01-01

We investigated the effect of different urban traffic-flow patterns on pollutant dispersion in different winds in a real asymmetric street canyon. Free-flow traffic causes more turbulence in the canyon facilitating more dispersion and a reduction in pedestrian level concentration. The comparison of with and without a vehicle-induced-turbulence revealed that when winds were perpendicular, the free-flow traffic reduced the concentration by 73% on the windward side with a minor increase of 17% on the leeward side, whereas for parallel winds, it reduced the concentration by 51% and 29%. The congested-flow traffic increased the concentrations on the leeward side by 47% when winds were perpendicular posing a higher risk to health, whereas reduced it by 17-42% for parallel winds. The urban air quality and public health can, therefore, be improved by improving the traffic-flow patterns in street canyons as vehicle-induced turbulence has been shown to contribute significantly to dispersion. Copyright © 2015 Elsevier Ltd. All rights reserved.

Road Traffic Anomaly Detection via Collaborative Path Inference from GPS Snippets

PubMed Central

Wang, Hongtao; Wen, Hui; Yi, Feng; Zhu, Hongsong; Sun, Limin

2017-01-01

Road traffic anomaly denotes a road segment that is anomalous in terms of traffic flow of vehicles. Detecting road traffic anomalies from GPS (Global Position System) snippets data is becoming critical in urban computing since they often suggest underlying events. However, the noisy and sparse nature of GPS snippets data have ushered multiple problems, which have prompted the detection of road traffic anomalies to be very challenging. To address these issues, we propose a two-stage solution which consists of two components: a Collaborative Path Inference (CPI) model and a Road Anomaly Test (RAT) model. CPI model performs path inference incorporating both static and dynamic features into a Conditional Random Field (CRF). Dynamic context features are learned collaboratively from large GPS snippets via a tensor decomposition technique. Then RAT calculates the anomalous degree for each road segment from the inferred fine-grained trajectories in given time intervals. We evaluated our method using a large scale real world dataset, which includes one-month GPS location data from more than eight thousand taxicabs in Beijing. The evaluation results show the advantages of our method beyond other baseline techniques. PMID:28282948

Road traffic impact on urban water quality: a step towards integrated traffic, air and stormwater modelling.

PubMed

Fallah Shorshani, Masoud; Bonhomme, Céline; Petrucci, Guido; André, Michel; Seigneur, Christian

2014-04-01

Methods for simulating air pollution due to road traffic and the associated effects on stormwater runoff quality in an urban environment are examined with particular emphasis on the integration of the various simulation models into a consistent modelling chain. To that end, the models for traffic, pollutant emissions, atmospheric dispersion and deposition, and stormwater contamination are reviewed. The present study focuses on the implementation of a modelling chain for an actual urban case study, which is the contamination of water runoff by cadmium (Cd), lead (Pb), and zinc (Zn) in the Grigny urban catchment near Paris, France. First, traffic emissions are calculated with traffic inputs using the COPERT4 methodology. Next, the atmospheric dispersion of pollutants is simulated with the Polyphemus line source model and pollutant deposition fluxes in different subcatchment areas are calculated. Finally, the SWMM water quantity and quality model is used to estimate the concentrations of pollutants in stormwater runoff. The simulation results are compared to mass flow rates and concentrations of Cd, Pb and Zn measured at the catchment outlet. The contribution of local traffic to stormwater contamination is estimated to be significant for Pb and, to a lesser extent, for Zn and Cd; however, Pb is most likely overestimated due to outdated emissions factors. The results demonstrate the importance of treating distributed traffic emissions from major roadways explicitly since the impact of these sources on concentrations in the catchment outlet is underestimated when those traffic emissions are spatially averaged over the catchment area.

Prediction algorithms for urban traffic control

DOT National Transportation Integrated Search

1979-02-01

The objectives of this study are to 1) review and assess the state-of-the-art of prediction algorithms for urban traffic control in terms of their accuracy and application, and 2) determine the prediction accuracy obtainable by examining the performa...

Carbon emissions tax policy of urban road traffic and its application in Panjin, China

PubMed Central

Yang, Longhai; Fang, Lin

2018-01-01

How to effectively solve traffic congestion and transportation pollution in urban development is a main research emphasis for transportation management agencies. A carbon emissions tax can affect travelers’ generalized costs and will lead to changes in passenger demand, mode choice and traffic flow equilibrium in road networks, which are of significance in green travel and low-carbon transportation management. This paper first established a mesoscopic model to calculate the carbon emissions tax and determined the value of this charge in China, which was based on road traffic flow, vehicle speed, and carbon emissions. Referring to existing research results to calibrate the value of time, this paper modified the traveler’s generalized cost function, including the carbon emissions tax, fuel surcharge and travel time cost, which can be used in the travel impedance model with the consideration of the carbon emissions tax. Then, a method for analyzing urban road network traffic flow distribution was put forward, and a joint traffic distribution model was established, which considered the relationship between private cars and taxis. Finally, this paper took the city of Panjin as an example to analyze the road traffic carbon emissions tax’s impact. The results illustrated that the carbon emissions tax has a positive effect on road network flow equilibrium and carbon emission reduction. This paper will have good reference value and practical significance for the calculation and implementation of urban traffic carbon emissions taxes in China. PMID:29738580

Carbon emissions tax policy of urban road traffic and its application in Panjin, China.

PubMed

Yang, Longhai; Hu, Xiaowei; Fang, Lin

2018-01-01

How to effectively solve traffic congestion and transportation pollution in urban development is a main research emphasis for transportation management agencies. A carbon emissions tax can affect travelers' generalized costs and will lead to changes in passenger demand, mode choice and traffic flow equilibrium in road networks, which are of significance in green travel and low-carbon transportation management. This paper first established a mesoscopic model to calculate the carbon emissions tax and determined the value of this charge in China, which was based on road traffic flow, vehicle speed, and carbon emissions. Referring to existing research results to calibrate the value of time, this paper modified the traveler's generalized cost function, including the carbon emissions tax, fuel surcharge and travel time cost, which can be used in the travel impedance model with the consideration of the carbon emissions tax. Then, a method for analyzing urban road network traffic flow distribution was put forward, and a joint traffic distribution model was established, which considered the relationship between private cars and taxis. Finally, this paper took the city of Panjin as an example to analyze the road traffic carbon emissions tax's impact. The results illustrated that the carbon emissions tax has a positive effect on road network flow equilibrium and carbon emission reduction. This paper will have good reference value and practical significance for the calculation and implementation of urban traffic carbon emissions taxes in China.

Hourly elemental concentrations in PM2.5 aerosols sampled simultaneously at urban background and road site during SAPUSS - diurnal variations and PMF receptor modelling

NASA Astrophysics Data System (ADS)

Dall'Osto, M.; Querol, X.; Amato, F.; Karanasiou, A.; Lucarelli, F.; Nava, S.; Calzolai, G.; Chiari, M.

2013-04-01

Hourly-resolved aerosol chemical speciation data can be a highly powerful tool to determine the source origin of atmospheric pollutants in urban environments. Aerosol mass concentrations of seventeen elements (Na, Mg, Al, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Sr and Pb) were obtained by time (1 h) and size (PM2.5 particulate matter < 2.5 μm) resolved aerosol samples analysed by Particle Induced X-ray Emission (PIXE) measurements. In the Marie Curie European Union framework of SAPUSS (Solving Aerosol Problems by Using Synergistic Strategies), the approach used is the simultaneous sampling at two monitoring sites in Barcelona (Spain) during September-October 2010: an urban background site (UB) and a street canyon traffic road site (RS). Elements related to primary non-exhaust traffic emission (Fe, Cu), dust resuspension (Ca) and anthropogenic Cl were found enhanced at the RS, whereas industrial related trace metals (Zn, Pb, Mn) were found at higher concentrations at the more ventilated UB site. When receptor modelling was performed with positive matrix factorization (PMF), nine different aerosol sources were identified at both sites: three types of regional aerosols (regional sulphate (S) - 27%, biomass burning (K) - 5%, sea salt (Na-Mg) - 17%), three types of dust aerosols (soil dust (Al-Ti) - 17%, urban crustal dust (Ca) - 6%, and primary traffic non-exhaust brake dust (Fe-Cu) - 7%), and three types of industrial aerosol plumes-like events (shipping oil combustion (V-Ni) - 17%, industrial smelters (Zn-Mn) - 3%, and industrial combustion (Pb-Cl) - 5%, percentages presented are average source contributions to the total elemental mass measured). The validity of the PMF solution of the PIXE data is supported by very good correlations with external single particle mass spectrometry measurements. Some important conclusions can be drawn about the PM2.5 mass fraction simultaneously measured at the UB and RS sites: (1) the regional aerosol sources impact both monitoring sites at similar concentrations regardless their different ventilation conditions; (2) by contrast, local industrial aerosol plumes associated with shipping oil combustion and smelters activities have a higher impact on the more ventilated UB site; (3) a unique source of Pb-Cl (associated with combustion emissions) is found to be the major (82%) source of fine Cl in the urban agglomerate; (4) the mean diurnal variation of PM2.5 primary traffic non-exhaust brake dust (Fe-Cu) suggests that this source is mainly emitted and not resuspended, whereas PM2.5 urban dust (Ca) is found mainly resuspended by both traffic vortex and sea breeze; (5) urban dust (Ca) is found the aerosol source most affected by land wetness, reduced by a factor of eight during rainy days and suggesting that wet roads may be a solution for reducing urban dust concentrations.

Pedestrian Friendly Traffic Signal Control.

DOT National Transportation Integrated Search

2016-01-01

This project continues research aimed at real-time detection and use of pedestrian : traffic flow information to enhance adaptive traffic signal control in urban areas : where pedestrian traffic is substantial and must be given appropriate attention ...

Residential Exposure to Urban Traffic Is Associated with Increased Carotid Intima-Media Thickness in Children

PubMed Central

Armijos, Rodrigo X.; Weigel, M. Margaret; Myers, Orrin B.; Li, Wen-Whai; Racines, Marcia; Berwick, Marianne

2015-01-01

Chronic exposure to urban traffic pollution is documented to promote atherosclerosis in adults but little is known about its potential effects in children. Our study examined the association of long-term exposure to traffic with carotid intima-media thickness (cIMT) in 287 healthy children. Residential proximity and distance-weighted traffic density (DWTD) were used as proximity markers for traffic-related air pollution exposure. The multivariable analyses revealed that children residing <100 meters from the nearest heavily trafficked road had cIMT mean and maximum measurements that were increased by 15% and 11% compared to those living ≥ 200 meters away (P = 0.0001). Similar increases in cIMT were identified for children in the highest versus lowest DWTD tertile. Children who resided 100–199 meters from traffic or in the middle DWTD tertile also exhibited increased cIMT but these differences were not statistically significant. No statistically significant differences were identified between residential distance to traffic or DWTD and systemic inflammation indicators (CRP, IL-6). The study results suggest that exposure to urban traffic promotes arterial remodeling in children. This finding is important since even small increases in cIMT over time can potentially lead to earlier progression to atherosclerosis. It is also important because traffic-related pollution is potentially modifiable. PMID:25685160

Residential exposure to urban traffic is associated with increased carotid intima-media thickness in children.

PubMed

Armijos, Rodrigo X; Weigel, M Margaret; Myers, Orrin B; Li, Wen-Whai; Racines, Marcia; Berwick, Marianne

2015-01-01

Chronic exposure to urban traffic pollution is documented to promote atherosclerosis in adults but little is known about its potential effects in children. Our study examined the association of long-term exposure to traffic with carotid intima-media thickness (cIMT) in 287 healthy children. Residential proximity and distance-weighted traffic density (DWTD) were used as proximity markers for traffic-related air pollution exposure. The multivariable analyses revealed that children residing <100 meters from the nearest heavily trafficked road had cIMT mean and maximum measurements that were increased by 15% and 11% compared to those living ≥ 200 meters away (P = 0.0001). Similar increases in cIMT were identified for children in the highest versus lowest DWTD tertile. Children who resided 100-199 meters from traffic or in the middle DWTD tertile also exhibited increased cIMT but these differences were not statistically significant. No statistically significant differences were identified between residential distance to traffic or DWTD and systemic inflammation indicators (CRP, IL-6). The study results suggest that exposure to urban traffic promotes arterial remodeling in children. This finding is important since even small increases in cIMT over time can potentially lead to earlier progression to atherosclerosis. It is also important because traffic-related pollution is potentially modifiable.

Trends of NOx, NO2 and O3 concentrations at three different types of air quality monitoring stations in Athens, Greece

NASA Astrophysics Data System (ADS)

Mavroidis, I.; Ilia, M.

2012-12-01

This work presents a systematic analysis and evaluation of the historic and current levels of atmospheric pollution in the Athens metropolitan region, regarding nitrogen oxides (NOx = NO + NO2), ozone (O3) and the NO2/NOx and NO/NO2 concentration ratios. Hourly, daily, monthly, seasonal and annual pollutant variations are examined and compared, using the results of concentration time series from three different stations of the national network for air pollution monitoring, one urban-traffic, one urban-background and one suburban-background. Concentration data are also related to meteorological parameters. The results show that the traffic affected station of Patission Street presents the higher NOx values and the lower concentrations of O3, while it is the station with the highest number of NO2 limit exceedances. The monitoring data suggest, inter alia, that there is a change in the behaviour of the suburban-background station of Liossia at about year 2000, indicating that the exact location of this station may need to be reconsidered. Comparison of NOx concentrations in Athens with concentrations in urban areas of other countries reveal that the Patission urban-traffic station records very high NOx concentrations, while remarkably high is the ratio of NO2 concentrations recorded at the urban-traffic vs. the urban-background station in Athens, indicating the overarching role of vehicles and traffic congestion on NO2 formation. The NO2/NOx ratio in the urban-traffic station appears to be almost constant with time, while it has been increasing in other urban areas, such as London and Seoul, suggesting an increased effect of primary NO2 in these areas. Diesel passenger cars were only recently allowed in Athens and, therefore, NO2 trends should be carefully monitored since a possible increase in primary NO2 may affect compliance with NO2 air quality standards.

Minnesota urban partnership agreement national evaluation : traffic system data test plan.

DOT National Transportation Integrated Search

2009-11-17

This report presents the traffic system data test plan for the Minnesota Urban Partnership Agreement (UPA) under the United States Department of Transportation (U.S. DOT) UPA Program. The Minnesota UPA projects focus on reducing congestion by employi...

A resilience-oriented approach for quantitatively assessing recurrent spatial-temporal congestion on urban roads.

PubMed

Tang, Junqing; Heinimann, Hans Rudolf

2018-01-01

Traffic congestion brings not only delay and inconvenience, but other associated national concerns, such as greenhouse gases, air pollutants, road safety issues and risks. Identification, measurement, tracking, and control of urban recurrent congestion are vital for building a livable and smart community. A considerable amount of works has made contributions to tackle the problem. Several methods, such as time-based approaches and level of service, can be effective for characterizing congestion on urban streets. However, studies with systemic perspectives have been minor in congestion quantification. Resilience, on the other hand, is an emerging concept that focuses on comprehensive systemic performance and characterizes the ability of a system to cope with disturbance and to recover its functionality. In this paper, we symbolized recurrent congestion as internal disturbance and proposed a modified metric inspired by the well-applied "R4" resilience-triangle framework. We constructed the metric with generic dimensions from both resilience engineering and transport science to quantify recurrent congestion based on spatial-temporal traffic patterns and made the comparison with other two approaches in freeway and signal-controlled arterial cases. Results showed that the metric can effectively capture congestion patterns in the study area and provides a quantitative benchmark for comparison. Also, it suggested not only a good comparative performance in measuring strength of proposed metric, but also its capability of considering the discharging process in congestion. The sensitivity tests showed that proposed metric possesses robustness against parameter perturbation in Robustness Range (RR), but the number of identified congestion patterns can be influenced by the existence of ϵ. In addition, the Elasticity Threshold (ET) and the spatial dimension of cell-based platform differ the congestion results significantly on both the detected number and intensity. By tackling this conventional problem with emerging concept, our metric provides a systemic alternative approach and enriches the toolbox for congestion assessment. Future work will be conducted on a larger scale with multiplex scenarios in various traffic conditions.

Powered two-wheeler drivers' risk of hitting a pedestrian in towns.

PubMed

Clabaux, Nicolas; Fournier, Jean-Yves; Michel, Jean-Emmanuel

2014-12-01

The risk of collision between pedestrians and powered two-wheelers is poorly understood today. The objective of this research is to determine the risk for powered two-wheeler drivers of hitting and injuring a pedestrian per kilometer driven in towns and to compare this risk with that run by four-wheeled vehicle drivers. Using the bodily injury accidents recorded by the police on nine roads in the city of Marseille in 2011 and a campaign of observations of powered two-wheeler traffic, we estimated the risk per kilometer driven by powered two-wheeler drivers of hitting a pedestrian and compared it with the risk run by four-wheeled vehicle drivers. The results show that the risk for powered two-wheeler drivers of hitting and injuring a pedestrian is significantly higher than the risk run by four-wheeled vehicle drivers. On the nine roads studied, it is on average 3.33 times higher (95% CI: 1.63; 6.78). Taking four more years into account made it possible to consolidate these results and to tighten the confidence interval. There does indeed seem to be problems in the interactions between pedestrians and powered two-wheeler users in urban traffic. These interaction problems lead to a higher risk of hitting and injuring a pedestrian for powered two-wheeler drivers than for four-wheeled vehicle drivers. The analysis of the police reports suggests that part of this increased risk comes from filtering maneuvers by powered two-wheelers. Possible countermeasures deal with the urban street layout. Measures consisting in reducing the width and the number of traffic lanes to a strict minimum and installing medians or pedestrian islands could be an effective way for the prevention of urban accidents between pedestrians and powered two-wheelers. Copyright © 2014 National Safety Council and Elsevier Ltd. All rights reserved.

Network-constrained spatio-temporal clustering analysis of traffic collisions in Jianghan District of Wuhan, China

PubMed Central

Fan, Yaxin; Zhu, Xinyan; Guo, Wei; Guo, Tao

2018-01-01

The analysis of traffic collisions is essential for urban safety and the sustainable development of the urban environment. Reducing the road traffic injuries and the financial losses caused by collisions is the most important goal of traffic management. In addition, traffic collisions are a major cause of traffic congestion, which is a serious issue that affects everyone in the society. Therefore, traffic collision analysis is essential for all parties, including drivers, pedestrians, and traffic officers, to understand the road risks at a finer spatio-temporal scale. However, traffic collisions in the urban context are dynamic and complex. Thus, it is important to detect how the collision hotspots evolve over time through spatio-temporal clustering analysis. In addition, traffic collisions are not isolated events in space. The characteristics of the traffic collisions and their surrounding locations also present an influence of the clusters. This work tries to explore the spatio-temporal clustering patterns of traffic collisions by combining a set of network-constrained methods. These methods were tested using the traffic collision data in Jianghan District of Wuhan, China. The results demonstrated that these methods offer different perspectives of the spatio-temporal clustering patterns. The weighted network kernel density estimation provides an intuitive way to incorporate attribute information. The network cross K-function shows that there are varying clustering tendencies between traffic collisions and different types of POIs. The proposed network differential Local Moran’s I and network local indicators of mobility association provide straightforward and quantitative measures of the hotspot changes. This case study shows that these methods could help researchers, practitioners, and policy-makers to better understand the spatio-temporal clustering patterns of traffic collisions. PMID:29672551

Design guidelines for raised and traversable medians in urban areas.

DOT National Transportation Integrated Search

1983-01-01

Major urban and suburban streets must provide a high level of service for through traffic as well as access to abutting properties. To an extent, the provisions of traffic service and the accommodation of access needs are conflicting functions that a...

San Francisco urban partnership agreement, national evaluation : traffic system data test plan.

DOT National Transportation Integrated Search

2011-06-01

This report presents the test plan for collecting and analyzing traffic system data for the San Francisco Urban Partnership Agreement (UPA) under the United States Department of Transportation (U.S. DOT) UPA Program. The San Francisco UPA projects fo...

Improving safety in high-speed work zones : a Super 70 study : [summary].

DOT National Transportation Integrated Search

2011-08-01

Highway work zones, particularly those on urban high-speed roads, require special attention and adequate traffic management to reduce the adverse impact of altered geometry and traffic that differ from typical conditions. Super 70 was an urban recons...

Effects of the amount of feedback information on urban traffic with advanced traveler information system

NASA Astrophysics Data System (ADS)

Chen, Jie; Li, Ming; Jiang, Rui; Hu, Mao-Bin

2017-09-01

In a real traffic system, information feedback has already been proven to be a good way to alleviate traffic jams. However, due to the massive traffic information of real system, the procedure is often difficult in practice. In this paper, we study the effects of the amount of feedback information based on a cellular automaton model of urban traffic. What we found most interesting is that when providing the traffic information of a part of a road to travelers, the performance of the system will be better than that providing the road's full traffic information. From this basis, we can provide more effective routing strategy with less information. We demonstrate that only providing the traffic information of about first half road from upstream to downstream can maximize the traffic capacity of the system. We also give an explanation for these phenomena by studying the distribution pattern of vehicles and the detailed turning environment at the intersections. The effects of the traffic light period are also provided.

Urban sprawl as a risk factor in motor vehicle occupant and pedestrian fatalities.

PubMed

Ewing, Reid; Schieber, Richard A; Zegeer, Charles V

2003-09-01

We sought to determine the association between urban sprawl and traffic fatalities. We created a sprawl index by applying principal components analysis to data for 448 US counties in the largest 101 metropolitan areas. Regression analysis was used to determine associations between the index and traffic fatalities. For every 1% increase in the index (i.e., more compact, less sprawl), all-mode traffic fatality rates fell by 1.49% (P <.001) and pedestrian fatality rates fell by 1.47% to 3.56%, after adjustment for pedestrian exposure (P <.001). Urban sprawl was directly related to traffic fatalities and pedestrian fatalities. Subsequent studies should investigate relationships at a finer geographic scale and should strive to improve on the measure of exposure used to adjust pedestrian fatality rates.

A quantitative estimation of the exhaust, abrasion and resuspension components of particulate traffic emissions using electron microscopy

NASA Astrophysics Data System (ADS)

Weinbruch, Stephan; Worringen, Annette; Ebert, Martin; Scheuvens, Dirk; Kandler, Konrad; Pfeffer, Ulrich; Bruckmann, Peter

2014-12-01

The contribution of the three traffic-related components exhaust, abrasion, and resuspension to kerbside and urban background PM10 and PM1 levels was quantified based on the analysis of individual particles by scanning electron microscopy. A total of 160 samples was collected on 38 days between February and September 2009 at a kerbside and an urban background station in the urban/industrial Ruhr area (Germany). Based on size, morphology, chemical composition and stability under electron bombardment, the 111,003 particles studied in detail were classified into the following 14 particle classes: traffic/exhaust, traffic/abrasion, traffic/resuspension, carbonaceous/organic, industry/metallurgy, industry/power plants, secondary particles, (aged) sea salt, silicates, Ca sulfates, carbonates, Fe oxides/hydroxides, biological particles, and other particles. The traffic/exhaust component consists predominantly of externally mixed soot particles and soot internally mixed with secondary particles. The traffic/abrasion component contains all particles with characteristic tracer elements (Fe, Cu, Ba, Sb, Zn) for brake and tire abrasion. The traffic/resuspension component is defined by the mixing state and comprises all internally mixed particles with a high proportion of silicates or Fe oxides/hydroxides which contain soot or abrasion particles as minor constituent. In addition, silicates and Fe oxides/hydroxides internally mixed with chlorine and sulphur containing particles were also assigned to the traffic/resuspension component. The total contribution of traffic to PM10 was found to be 27% at the urban background station and 48% at the kerbside station, the corresponding values for PM1 are 15% and 39%. These values lie within the range reported in previous literature. The relative share of the different traffic components for PM10 at the kerbside station was 27% exhaust, 15% abrasion, and 58% resuspension (38%, 8%, 54% for PM1). For the urban background, the following relative shares were obtained for PM10: 22% exhaust, 22% abrasion and 56% resuspension (40%, 27%, 33% for PM1). Compared to previous publications we have observed a significantly lower portion of exhaust particles and a significantly higher portion of resuspension particles. The high abundance of resuspension particles underlines their significance for the observed adverse health effects of traffic emissions and for mitigation measures.

Pedestrian friendly traffic signal control : final research report.

DOT National Transportation Integrated Search

2016-01-01

This project continues research aimed at real-time detection and use of pedestrian : traffic flow information to enhance adaptive traffic signal control in urban areas : where pedestrian traffic is substantial and must be given appropriate attention ...

Soft Mobility as a Smart Condition in a Mountain City

NASA Astrophysics Data System (ADS)

Virtudes, Ana; Azevedo, Henrique; Abbara, Arwa; Sá, João

2017-10-01

Nowadays soft mobility is a crucial issue towards a most sustainable urban environment. Not only because it promotes a less polluted atmosphere among the always dense and busy urban fabric, but also because it avoids several traffic problems. The use of bicycles, or mechanic mechanisms to support the pedestrian mobility is an emerging requirement of cities’ quality. In this sense, this article aims to discuss the soft mobility as a requirement of smart cities having as a case study one mountain urban area. It refers to the urban area of Covilhã on the highest mountain of Portugal with nearly two thousand meters high. During the last decades, this city’s transformation process has driven to an urban sprawl to the suburbs, increasing the efforts in terms of transportation required by the commuters. In fact, the number of inhabitants living in the city centre is decreasing in favour of the peripheral neighbourhoods. At the same time a set of several mechanic mechanisms such as public lifts, has been built in order to promote a soft pedestrian mobility. However, in many cases, because of the lack of connection and continuity of pedestrian paths in between these mechanisms, they are not allowing a pedestrian mobility network at the city scale. Thus, this paper aims to present a set of good practices in terms of pedestrian mobility network at the city scale, in order to promote a smarter urban environment. The principal results are that soft mobility is a key issue in order to turn cities smarter, among several other factors such as smart economy, smart people, smart governance or smart living. The major conclusions show that the concerns with mobility are key tools to achieve the smart city sustainability, providing and efficient and flexible traveling across the urban fabric, boosting the use of non-polluting ways of mobility. At the same time, there is the conclusion that the underlying areas of development for a smart city, despite its cultural or territorial environments, include several aspects such as reducing the transportation problems as congestion, traffic jams or painful accidents.

Environmental and biological monitoring of benzene in traffic policemen, police drivers and rural outdoor male workers.

PubMed

Manuela, Ciarrocca; Francesco, Tomei; Tiziana, Caciari; Assunta, Capozzella; Lara, Scimitto; Nadia, Nardone; Giorgia, Andreozzi; Barbara, Scala; Maria, Fiaschetti; Carlotta, Cetica; Valeria, Di Giorgio; Pia, Schifano Maria; Gianfranco, Tomei; Angela, Sancini

2012-05-01

To evaluate exposure to benzene in urban and rural areas, an investigation into personal exposure to benzene in traffic policemen, police drivers and rural (roadmen) male outdoor workers was carried out. Personal samples and data acquired using fixed monitoring stations located in different areas of the city were used to measure personal exposure to benzene in 62 non-smoker traffic policemen, 22 police drivers and 57 roadmen. Blood benzene, urinary trans-trans muconic acid (t,t-MA) and S-phenyl-mercapturic acid (S-PMA) were measured at the end of work shift in 62 non-smoker traffic policemen, 22 police drivers and 57 roadmen and 34 smoker traffic policemen, 21 police drivers and 53 roadmen. Exposure to benzene was similar among non-smoker traffic policemen and police drivers and higher among non-smoker urban workers compared to rural workers. Blood benzene, t,t-MA and S-PMA were similar among non-smoker traffic policemen and police drivers; blood benzene and t,t-MA were significantly higher in non-smoker urban workers compared to rural workers. Significant increases in t,t-MA were found in smokers vs. non-smokers. In non-smoker urban workers airborne benzene and blood benzene, and t,t-MA and S-PMA were significantly correlated. This study gives an evaluation of the exposure to benzene in an urban area, comparing people working in the street or in cars, to people working in a rural area. Benzene is a certain carcinogen for humans. The results we showed should lead to more in-depth studies about the effects on health of these categories of workers.

Assessment of ultrafine particles and noise measurements using fuzzy logic and data mining techniques.

PubMed

Fernández-Camacho, R; Brito Cabeza, I; Aroba, J; Gómez-Bravo, F; Rodríguez, S; de la Rosa, J

2015-04-15

This study focuses on correlations between total number concentrations, road traffic emissions and noise levels in an urban area in the southwest of Spain during the winter and summer of 2009. The high temporal correlation between sound pressure levels, traffic intensity, particle number concentrations related to traffic, black carbon and NOx concentrations suggests that noise is linked to traffic emissions as a main source of pollution in urban areas. First, the association of these different variables was studied using PreFuRGe, a computational tool based on data mining and fuzzy logic. The results showed a clear association between noise levels and road-traffic intensity for non-extremely high wind speed levels. This behaviour points, therefore, to vehicular emissions being the main source of urban noise. An analysis for estimating the total number concentration from noise levels is also proposed in the study. The high linearity observed between particle number concentrations linked to traffic and noise levels with road traffic intensity can be used to calculate traffic related particle number concentrations experimentally. At low wind speeds, there are increases in noise levels of 1 dB for every 100 vehicles in circulation. This is equivalent to 2000 cm(-3) per vehicle in winter and 500 cm(-3) in summer. At high wind speeds, wind speed could be taken into account. This methodology allows low cost sensors to be used as a proxy for total number concentration monitoring in urban air quality networks. Copyright © 2015 Elsevier B.V. All rights reserved.

Improving the roadside environment through integrating air quality and traffic-related data.

DOT National Transportation Integrated Search

2016-12-01

Urban arterial corridors are landscapes that give rise to short and long-term : exposures to transportation-related pollution. With high traffic volumes, congestion, and : a wide mix of road users and land uses at the road edge, urban arterial enviro...

Bicyclists' Uptake of Traffic-Related Air Pollution: Effects of the Urban Transportation System

DOT National Transportation Integrated Search

2014-10-27

While bicyclists and other active travelers obtain health benefits from increased physical activity, they also risk uptake of traffic-related air pollution. But pollution uptake by urban bicyclists is not well understood due to a lack of direct measu...

Wild growing mushrooms for the Edible City? Cadmium and lead content in edible mushrooms harvested within the urban agglomeration of Berlin, Germany.

PubMed

Schlecht, Martin Thomas; Säumel, Ina

2015-09-01

Health effects by consuming urban garden products are discussed controversially due to high urban pollution loads. We sampled wild edible mushrooms of different habitats and commercial mushroom cultivars exposed to high traffic areas within Berlin, Germany. We determined the content of cadmium and lead in the fruiting bodies and analysed how the local setting shaped the concentration patterns. EU standards for cultivated mushrooms were exceeded by 86% of the wild mushroom samples for lead and by 54% for cadmium but not by mushroom cultures. We revealed significant differences in trace metal content depending on species, trophic status, habitat and local traffic burden. Higher overall traffic burden increased trace metal content in the biomass of wild mushrooms, whereas cultivated mushrooms exposed to inner city high traffic areas had significantly lower trace metal contents. Based on these we discuss the consequences for the consumption of mushrooms originating from urban areas. Copyright © 2015 Elsevier Ltd. All rights reserved.

Opportunities for Environmental Noise Mapping in Saudi Arabia: A Case of Traffic Noise Annoyance in an Urban Area in Jeddah City.

PubMed

Zytoon, Mohamed A

2016-05-13

As the traffic and other environmental noise generating activities are growing in The Kingdom of Saudi Arabia (KSA), adverse health and other impacts are expected to develop. The management of such problem involves many actions, of which noise mapping has been proven to be a helpful approach. The objective of the current study was to test the adequacy of the available data in KSA municipalities for generating urban noise maps and to verify the applicability of available environmental noise mapping and noise annoyance models for KSA. Therefore, noise maps were produced for Al-Fayha District in Jeddah City, KSA using commercially available noise mapping software and applying the French national computation method "NMPB" for traffic noise. Most of the data required for traffic noise prediction and annoyance analysis were available, either in the Municipality GIS department or in other governmental authorities. The predicted noise levels during the three time periods, i.e., daytime, evening, and nighttime, were found higher than the maximum recommended levels established in KSA environmental noise standards. Annoyance analysis revealed that high percentages of the District inhabitants were highly annoyed, depending on the type of planning zone and period of interest. These results reflect the urgent need to consider environmental noise reduction in KSA national plans. The accuracy of the predicted noise levels and the availability of most of the necessary data should encourage further studies on the use of noise mapping as part of noise reduction plans.

Influences of traffic on Pb, Cu and Zn concentrations in roadside soils of an urban park in Dublin, Ireland.

PubMed

Dao, Ligang; Morrison, Liam; Zhang, Hongxuan; Zhang, Chaosheng

2014-06-01

Soils in the vicinity of roads are recipients of contaminants from traffic emissions. In order to obtain a better understanding of the impacts of traffic on soils, a total of 225 surface soil samples were collected from an urban park (Phoenix Park, Dublin, Ireland) in a grid system. Metal (Pb, Cu and Zn) concentrations were determined using a portable X-ray fluorescence analyzer. Strong spatial variations for the concentrations of Pb, Cu and Zn were observed. The spatial distribution maps created using geographical information system techniques revealed elevated metal concentrations close to the main traffic route in the park. The relationships between the accumulation of Pb, Cu and Zn in the roadside soils and the distance from the road were well fitted with an exponential model. Elevated metal concentrations from traffic pollution extended to a distance of approximately 40 m from the roadside. The results of this study provide useful information for the management of urban parks particularly in relation to policies aimed at reducing the impact of traffic related pollution on soils.

Neighborhood Social Inequalities in Road Traffic Injuries: The Influence of Traffic Volume and Road Design

PubMed Central

Gauvin, Lise; Plante, Céline; Fournier, Michel; Morency, Catherine

2012-01-01

Objectives. We examined the extent to which differential traffic volume and road geometry can explain social inequalities in pedestrian, cyclist, and motor vehicle occupant injuries across wealthy and poor urban areas. Methods. We performed a multilevel observational study of all road users injured over 5 years (n = 19 568) at intersections (n = 17 498) in a large urban area (Island of Montreal, Canada). We considered intersection-level (traffic estimates, major roads, number of legs) and area-level (population density, commuting travel modes, household income) characteristics in multilevel Poisson regressions that nested intersections in 506 census tracts. Results. There were significantly more injured pedestrians, cyclists, and motor vehicle occupants at intersections in the poorest than in the richest areas. Controlling for traffic volume, intersection geometry, and pedestrian and cyclist volumes greatly attenuated the event rate ratios between intersections in the poorest and richest areas for injured pedestrians (−70%), cyclists (−44%), and motor vehicle occupants (−44%). Conclusions. Roadway environment can explain a substantial portion of the excess rate of road traffic injuries in the poorest urban areas. PMID:22515869

The Impact of Large Urban Structural Elements on Traffic Flow   a Case Study of Danwei and Xiaoqu in Shanghai

NASA Astrophysics Data System (ADS)

Lyu, H.; Ding, L.; Fan, H.; Meng, L.

2017-09-01

Danwei (working unit) and Xiaoqu (residential community) are two typical and unique structural urban elements in China. The interior roads of Danwei and Xiaoqu are usually not accessible for the public. Recently, there is a call for opening these interior roads to the public to improve road network structure and optimize traffic flow. In this paper we investigate the impact of Danwei and Xiaoqu on their neighbouring traffic quantitatively. By taking into consideration of origins and destinations (ODs) distributions and route selection behaviours (e.g., shortest paths), we propose an extended betweenness centrality to investigate the traffic flow in two scenarios 1) the interior roads of Danwei and Xiaoqu are excluded from urban road network, 2) the interior roads are integrated into road network. A Danwei and a Xiaoqu in Shanghai are used as the study area. The preliminary results show the feasibility of our extended betweenness centrality in investigating the traffic flow patterns and reveal the quantitative changes of the traffic flow after opening interior roads.

STUDY ON SUPPORTING FOR DRAWING UP THE BCP FOR URBAN EXPRESSWAY NETWORK USING BY TRAFFIC SIMULATION SYSTEM

NASA Astrophysics Data System (ADS)

Yamawaki, Masashi; Shiraki, Wataru; Inomo, Hitoshi; Yasuda, Keiichi

The urban expressway network is an important infrastructure to execute a disaster restoration. Therefore, it is necessary to draw up the BCP (Business Continuity Plan) to enable securing of road user's safety and restoration of facilities, etc. It is important that each urban expressway manager execute decision and improvement of effective BCP countermeasures when disaster occurs by assuming various disaster situations. Then, in this study, we develop the traffic simulation system that can reproduce various disaster situations and traffic actions, and examine some methods supporting for drawing up the BCP for an urban expressway network. For disaster outside assumption such as tsunami generated by a huge earthquake, we examine some approaches securing safety of users and cars on the Hanshin Expressway Network as well as on general roads. And, we aim to propose a tsunami countermeasure not considered in the current urban expressway BCP.

A Survey on Urban Traffic Management System Using Wireless Sensor Networks.

PubMed

Nellore, Kapileswar; Hancke, Gerhard P

2016-01-27

Nowadays, the number of vehicles has increased exponentially, but the bedrock capacities of roads and transportation systems have not developed in an equivalent way to efficiently cope with the number of vehicles traveling on them. Due to this, road jamming and traffic correlated pollution have increased with the associated adverse societal and financial effect on different markets worldwide. A static control system may block emergency vehicles due to traffic jams. Wireless Sensor networks (WSNs) have gained increasing attention in traffic detection and avoiding road congestion. WSNs are very trendy due to their faster transfer of information, easy installation, less maintenance, compactness and for being less expensive compared to other network options. There has been significant research on Traffic Management Systems using WSNs to avoid congestion, ensure priority for emergency vehicles and cut the Average Waiting Time (AWT) of vehicles at intersections. In recent decades, researchers have started to monitor real-time traffic using WSNs, RFIDs, ZigBee, VANETs, Bluetooth devices, cameras and infrared signals. This paper presents a survey of current urban traffic management schemes for priority-based signalling, and reducing congestion and the AWT of vehicles. The main objective of this survey is to provide a taxonomy of different traffic management schemes used for avoiding congestion. Existing urban traffic management schemes for the avoidance of congestion and providing priority to emergency vehicles are considered and set the foundation for further research.

Exposure to urban stressor and effects on free testosterone in female workers.

PubMed

Tomei, Gianfranco; Ciarrocca, Manuela; Fiore, Pina; Rosati, Maria Valeria; Pimpinella, Benedetta; Anzani, Maria Francesca; Giubilati, Roberto; Cangemi, Chiara; Tomao, Enrico; Tomei, Francesco

2008-03-25

The aim of the study is to evaluate if occupational exposure to chemical, physical and psycho-social urban stressor could cause alterations in plasma free testosterone (T) levels and related diseases in female traffic police vs. control group. The research was carried out on initial sample of 468 female Municipal Police employees (209 traffic police and 259 controls). After excluding the principal confounding factors, traffic police were matched with controls by age, working life, menstrual cycle day, BMI, drinking habit, cigarette smoking habit, liquorice and soy intake in diet, habitual consumption of Italian coffee. There were 96 female traffic police and 96 controls included in the study. T mean levels were significantly higher in female traffic police compared to controls (p=0.000). The distribution of T values in traffic police and in controls was significant (p=0.000). No significant differences were found comparing the percentage in traffic police and controls concerning dystocial, premature and post-term birth. An increase in mental health disorders was found in traffic police compared to controls but the difference was not significant. The increase in T plasma levels observed in traffic police vs. controls can be due to a chronic working exposure to low doses of environmental chemical urban stressor. According to our previous researches T could be used as an early biological marker even before the onset of the related disorders.

A Survey on Urban Traffic Management System Using Wireless Sensor Networks

PubMed Central

Nellore, Kapileswar; Hancke, Gerhard P.

2016-01-01

Nowadays, the number of vehicles has increased exponentially, but the bedrock capacities of roads and transportation systems have not developed in an equivalent way to efficiently cope with the number of vehicles traveling on them. Due to this, road jamming and traffic correlated pollution have increased with the associated adverse societal and financial effect on different markets worldwide. A static control system may block emergency vehicles due to traffic jams. Wireless Sensor networks (WSNs) have gained increasing attention in traffic detection and avoiding road congestion. WSNs are very trendy due to their faster transfer of information, easy installation, less maintenance, compactness and for being less expensive compared to other network options. There has been significant research on Traffic Management Systems using WSNs to avoid congestion, ensure priority for emergency vehicles and cut the Average Waiting Time (AWT) of vehicles at intersections. In recent decades, researchers have started to monitor real-time traffic using WSNs, RFIDs, ZigBee, VANETs, Bluetooth devices, cameras and infrared signals. This paper presents a survey of current urban traffic management schemes for priority-based signalling, and reducing congestion and the AWT of vehicles. The main objective of this survey is to provide a taxonomy of different traffic management schemes used for avoiding congestion. Existing urban traffic management schemes for the avoidance of congestion and providing priority to emergency vehicles are considered and set the foundation for further research. PMID:26828489

How Travel Demand Affects Detection of Non-Recurrent Traffic Congestion on Urban Road Networks

NASA Astrophysics Data System (ADS)

Anbaroglu, B.; Heydecker, B.; Cheng, T.

2016-06-01

Occurrence of non-recurrent traffic congestion hinders the economic activity of a city, as travellers could miss appointments or be late for work or important meetings. Similarly, for shippers, unexpected delays may disrupt just-in-time delivery and manufacturing processes, which could lose them payment. Consequently, research on non-recurrent congestion detection on urban road networks has recently gained attention. By analysing large amounts of traffic data collected on a daily basis, traffic operation centres can improve their methods to detect non-recurrent congestion rapidly and then revise their existing plans to mitigate its effects. Space-time clusters of high link journey time estimates correspond to non-recurrent congestion events. Existing research, however, has not considered the effect of travel demand on the effectiveness of non-recurrent congestion detection methods. Therefore, this paper investigates how travel demand affects detection of non-recurrent traffic congestion detection on urban road networks. Travel demand has been classified into three categories as low, normal and high. The experiments are carried out on London's urban road network, and the results demonstrate the necessity to adjust the relative importance of the component evaluation criteria depending on the travel demand level.

An Improved Response Surface Methodology Algorithm with an Application to Traffic Signal Optimization for Urban Networks

DOT National Transportation Integrated Search

1995-01-01

Prepared ca. 1995. This paper illustrates the use of the simulation-optimization technique of response surface methodology (RSM) in traffic signal optimization of urban networks. It also quantifies the gains of using the common random number (CRN) va...

The improved degree of urban road traffic network: A case study of Xiamen, China

NASA Astrophysics Data System (ADS)

Wang, Shiguang; Zheng, Lili; Yu, Dexin

2017-03-01

The complex network theory is applied to the study of urban road traffic network topology, and we constructed a new measure to characterize an urban road network. It is inspiring to quantify the interaction more appropriately between nodes in complex networks, especially in the field of traffic. The measure takes into account properties of lanes (e.g. number of lanes, width, traffic direction). As much, it is a more comprehensive measure in comparison to previous network measures. It can be used to grasp the features of urban street network more clearly. We applied this measure to the road network in Xiamen, China. Based on a standard method from statistical physics, we examined in more detail the distribution of this new measure and found that (1) due to the limitation of space geographic attributes, traditional research conclusions acquired by using the original definition of degree to study the primal approach modeled urban street network are not very persuasive; (2) both of the direction of the network connection and the degree's odd or even classifications need to be analyzed specifically; (3) the improved degree distribution presents obvious hierarchy, and hierarchical values conform to the power-law distribution, and correlation of our new measure shows some significant segmentation of the urban road network.

Exhaust Emissions Measured Under Real Traffic Conditions from Vehicles Fitted with Spark Ignition and Compression Ignition Engines

NASA Astrophysics Data System (ADS)

Merkisz, Jerzy; Lijewski, Piotr; Fuć, Paweł

2011-06-01

The tests performed under real traffic conditions provide invaluable information on the relations between the engine parameters, vehicle parameters and traffic conditions (traffic congestion) on one side and the exhaust emissions on the other. The paper presents the result of road tests obtained in an urban and extra-urban cycles for vehicles fitted with different engines, spark ignition engine and compression ignition engine. For the tests a portable emission analyzer SEMTECH DS. by SENSORS was used. This analyzer provides online measurement of the concentrations of exhaust emission components on a vehicle in motion under real traffic conditions. The tests were performed in city traffic. A comparative analysis has been presented of the obtained results for vehicles with individual powertrains.

Use of science to guide city planning policy and practice: how to achieve healthy and sustainable future cities.

PubMed

Sallis, James F; Bull, Fiona; Burdett, Ricky; Frank, Lawrence D; Griffiths, Peter; Giles-Corti, Billie; Stevenson, Mark

2016-12-10

Land-use and transport policies contribute to worldwide epidemics of injuries and non-communicable diseases through traffic exposure, noise, air pollution, social isolation, low physical activity, and sedentary behaviours. Motorised transport is a major cause of the greenhouse gas emissions that are threatening human health. Urban and transport planning and urban design policies in many cities do not reflect the accumulating evidence that, if policies would take health effects into account, they could benefit a wide range of common health problems. Enhanced research translation to increase the influence of health research on urban and transport planning decisions could address many global health problems. This paper illustrates the potential for such change by presenting conceptual models and case studies of research translation applied to urban and transport planning and urban design. The primary recommendation of this paper is for cities to actively pursue compact and mixed-use urban designs that encourage a transport modal shift away from private motor vehicles towards walking, cycling, and public transport. This Series concludes by urging a systematic approach to city design to enhance health and sustainability through active transport and a move towards new urban mobility. Such an approach promises to be a powerful strategy for improvements in population health on a permanent basis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Assessment of the influence of traffic-related particles in urban dust using sequential selective extraction and oral bioaccessibility tests.

PubMed

Patinha, C; Durães, N; Sousa, P; Dias, A C; Reis, A P; Noack, Y; Ferreira da Silva, E

2015-08-01

Urban dust is a heterogeneous mix, where traffic-related particles can combine with soil mineral compounds, forming a unique and site-specific material. These traffic-related particles are usually enriched in potentially harmful elements, enhancing the health risk for population by inhalation or ingestion. Urban dust samples from Estarreja city and traffic-related particles (brake dust and white traffic paint) were studied to understand the relative contribution of the traffic particles in the geochemical behaviour of urban dust and to evaluate the long-term impacts of the metals on an urban environment, as well as the risk to the populations. It was possible to distinguish two groups of urban dust samples according to Cu behaviour: (1) one group with low amounts of fine particles (<38 µm), low contents of organic material, high percentage of Cu in soluble phases, and low Cu bioaccessible fraction (Bf) values. This group showed similar chemical behaviour with the brake dust samples of low- to mid-range car brands (with more than 10 years old), composed by coarser wear particles; and (2) another group with greater amounts of fine particles (<38 µm), with low percentage of Cu associated with soluble phases, and with greater Cu Bf values. This group behaved similar to those found for brake dust of mid- to high-range car brands (with less than 10 years old). The results obtained showed that there is no direct correlation between the geoavailability of metals estimated by sequential selective chemical extraction (SSCE) and the in vitro oral bioaccessibility (UBM) test. Thus, oral bioaccessibility of urban dust is site specific. Geoavailability was greatly dependent on particle size, where the bioaccessibility tended to increase with a reduction in particle diameter. As anthropogenic particles showed high metal concentration and a smaller size than mineral particles, urban dusts are of major concern to the populations' health, since fine particles are easily re-suspended, easily ingested, and show high metal bioaccessibility. In addition, Estarreja is a coastal city often influenced by winds, which favours the re-suspension of small-sized contaminated particles. Even if the risk to the population does not represent an acute case, it should not be overlooked, and this study can serve as baseline study for cities under high traffic influence.

Hybrid and electric low-noise cars cause an increase in traffic accidents involving vulnerable road users in urban areas.

PubMed

Brand, Stephan; Petri, Maximilian; Haas, Philipp; Krettek, Christian; Haasper, Carl

2013-01-01

Due to resource scarcity, the number of low-noise and electric cars is expected to increase rapidly. The frequent use of these cars will lead to a significant reduction of traffic related noise and pollution. On the other hand, due to the adaption and conditioning of vulnerable road users the number of traffic accidents involving pedestrians and bicyclists is postulated to increase as well. Children, older people with reduced eyesight and the blind are especially reliant on a combination of acoustic and visual warning signals with approaching or accelerating vehicles. This is even more evident in urban areas where the engine sound is the dominating sound up to 30 kph (kilometres per hour). Above this, tyre-road interaction is the main cause of traffic noise. With the missing typical engine sound a new sound design is necessary to prevent traffic accidents in urban areas. Drivers should not be able to switch the sound generator off.

Incidence of real-world automotive parent and halogenated PAH in urban atmosphere.

PubMed

Gao, Pan-Pan; Zhao, Yi-Bo; Ni, Hong-Gang

2018-06-01

This study reports results from a tunnel experiment impact of real-world traffic-related particle and gas parent and halogenated polycyclic aromatic hydrocarbons (PAHs and HPAHs) on urban air. The traffic related emission characteristics and subsequent environmental behavior of these compounds were investigated. To understand the significance of real-world transport emissions to the urban air, traffic-related mass emissions of PAHs and HPAHs were estimated based on measured emission factors. According to our results, PAHs and HPAHs emissions via particulate phase were greater than those via gaseous phase; particles in 2.1-3.3 μm size fraction, have the major contribution to particulate PAHs and HPAHs emissions. Over all, contribution of traffic-related emission of PAHs (only ∼3% of the total PAHs emission in China) is an overstated source of PAHs pollution in China. Actually, exhaust pipe emission contributed much less than the total traffic-related emission of pollutants. Copyright © 2018 Elsevier Ltd. All rights reserved.

Indiana freeway traffic characteristics and dynamic prediction of freeway traffic flows

DOT National Transportation Integrated Search

1999-12-01

Traffic volumes on Indiana's roadways have increased significantly in the past years. During the period between 1989 and 1993, traffic volumes increased 20.2% on Indiana's urban interstate freeways and expressways, and 13.1% on rural interstates. The...

Leveraging traffic and surveillance video cameras for urban traffic.

DOT National Transportation Integrated Search

2014-12-01

The objective of this project was to investigate the use of existing video resources, such as traffic : cameras, police cameras, red light cameras, and security cameras for the long-term, real-time : collection of traffic statistics. An additional ob...

Source apportionment of organic pollutants of a highway-traffic-influenced urban area in Bayreuth (Germany) using biomarker and stable carbon isotope signatures.

PubMed

Glaser, Bruno; Dreyer, Annekatrin; Bock, Michael; Fiedler, Stefan; Mehring, Marion; Heitmann, Tobias

2005-06-01

Traffic- and urban-influenced areas are prone to enhanced pollution with products of incomplete combustion of fossil fuels and biomass such as black carbon or polycyclic aromatic hydrocarbons (PAHs). Black carbon is composed of aromatic and graphitic structures and may act as a carrier for pollutants such as PAHs and heavy metals. However, little is known about possible contributions of traffic-derived black carbon to the black carbon inventory in soils. Similar uncertainties exist regarding the contribution of different pollutant sources to total PAH and black carbon contents. Therefore, the objective of this study was to quantify the importance of traffic pollution to black carbon and PAH inventories in soils. PAH contamination of soils adjacent to a major German highway in the urban area of Bayreuth with about 50,000 vehicles per day was in the same order of magnitude compared to highway-close soils reported in other studies. Using molecular (black carbon and PAHs) and compound-specific stable carbon isotope evidence (PAHs) it was demonstrated that this contamination originated not only from automobile exhausts, here primarily diesel, but also from tire abrasion and tailpipe soot which significantly contributed to the traffic-caused black carbon and PAH contamination. Low molecular weight PAHs were more widely transported than their heavy molecular counterparts (local distillation), whereas highway-traffic-caused black carbon contamination was distributed to at least 30 m from the highway. On the other hand, urban fire exhausts were distributed more homogeneously among the urban area.

Spatial distribution of traffic induced noise exposures in a US city: an analytic tool for assessing the health impacts of urban planning decisions

PubMed Central

Seto, Edmund Yet Wah; Holt, Ashley; Rivard, Tom; Bhatia, Rajiv

2007-01-01

Background: Vehicle traffic is the major source of noise in urban environments, which in turn has multiple impacts on health. In this paper we investigate the spatial distribution of community noise exposures and annoyance. Traffic data from the City of San Francisco were used to model noise exposure by neighborhood and road type. Remote sensing data were used in the model to estimate neighborhood-specific percentages of cars, trucks, and buses on arterial versus non-arterial streets. The model was validated on 235 streets. Finally, an exposure-response relationship was used to predict the prevalence of high annoyance for different neighborhoods. Results: Urban noise was found to increase 6.7 dB (p < 0.001) with 10-fold increased street traffic, with important contributors to noise being bus and heavy truck traffic. Living along arterial streets also increased risk of annoyance by 40%. The relative risk of annoyance in one of the City's fastest growing neighborhoods, the South of Market Area, was found to be 2.1 times that of lowest noise neighborhood. However, higher densities of exposed individuals were found in Chinatown and Downtown/Civic Center. Overall, we estimated that 17% of the city's population was at risk of high annoyance from traffic noise. Conclusion: The risk of annoyance from urban noise is large, and varies considerably between neighborhoods. Such risk should be considered in urban areas undergoing rapid growth. We present a relatively simple GIS-based noise model that may be used for routinely evaluating the health impacts of environmental noise. PMID:17584947

Urban Sprawl as a Risk Factor in Motor Vehicle Occupant and Pedestrian Fatalities

PubMed Central

Ewing, Reid; Schieber, Richard A.; Zegeer, Charles V.

2003-01-01

Objectives. We sought to determine the association between urban sprawl and traffic fatalities. Methods. We created a sprawl index by applying principal components analysis to data for 448 US counties in the largest 101 metropolitan areas. Regression analysis was used to determine associations between the index and traffic fatalities. Results. For every 1% increase in the index (i.e., more compact, less sprawl), all-mode traffic fatality rates fell by 1.49% (P < .001) and pedestrian fatality rates fell by 1.47% to 3.56%, after adjustment for pedestrian exposure (P < .001). Conclusions. Urban sprawl was directly related to traffic fatalities and pedestrian fatalities. Subsequent studies should investigate relationships at a finer geographic scale and should strive to improve on the measure of exposure used to adjust pedestrian fatality rates. PMID:12948977

Optimized Sensor Network and Multi-Agent Decision Support for Smart Traffic Light Management.

PubMed

Cruz-Piris, Luis; Rivera, Diego; Fernandez, Susel; Marsa-Maestre, Ivan

2018-02-02

One of the biggest challenges in modern societies is to solve vehicular traffic problems. Sensor networks in traffic environments have contributed to improving the decision-making process of Intelligent Transportation Systems. However, one of the limiting factors for the effectiveness of these systems is in the deployment of sensors to provide accurate information about the traffic. Our proposal is using the centrality measurement of a graph as a base to locate the best locations for sensor installation in a traffic network. After integrating these sensors in a simulation scenario, we define a Multi-Agent Systems composed of three types of agents: traffic light management agents, traffic jam detection agents, and agents that control the traffic lights at an intersection. The ultimate goal of these Multi-Agent Systems is to improve the trip duration for vehicles in the network. To validate our solution, we have developed the needed elements for modelling the sensors and agents in the simulation environment. We have carried out experiments using the Simulation of Urban MObility (SUMO) traffic simulator and the Travel and Activity PAtterns Simulation (TAPAS) Cologne traffic scenario. The obtained results show that our proposal allows to reduce the sensor network while still obtaining relevant information to have a global view of the environment. Finally, regarding the Multi-Agent Systems, we have carried out experiments that show that our proposal is able to improve other existing solutions such as conventional traffic light management systems (static or dynamic) in terms of reduction of vehicle trip duration and reduction of the message exchange overhead in the sensor network.

Optimized Sensor Network and Multi-Agent Decision Support for Smart Traffic Light Management

PubMed Central

2018-01-01

One of the biggest challenges in modern societies is to solve vehicular traffic problems. Sensor networks in traffic environments have contributed to improving the decision-making process of Intelligent Transportation Systems. However, one of the limiting factors for the effectiveness of these systems is in the deployment of sensors to provide accurate information about the traffic. Our proposal is using the centrality measurement of a graph as a base to locate the best locations for sensor installation in a traffic network. After integrating these sensors in a simulation scenario, we define a Multi-Agent Systems composed of three types of agents: traffic light management agents, traffic jam detection agents, and agents that control the traffic lights at an intersection. The ultimate goal of these Multi-Agent Systems is to improve the trip duration for vehicles in the network. To validate our solution, we have developed the needed elements for modelling the sensors and agents in the simulation environment. We have carried out experiments using the Simulation of Urban MObility (SUMO) traffic simulator and the Travel and Activity PAtterns Simulation (TAPAS) Cologne traffic scenario. The obtained results show that our proposal allows to reduce the sensor network while still obtaining relevant information to have a global view of the environment. Finally, regarding the Multi-Agent Systems, we have carried out experiments that show that our proposal is able to improve other existing solutions such as conventional traffic light management systems (static or dynamic) in terms of reduction of vehicle trip duration and reduction of the message exchange overhead in the sensor network. PMID:29393884

Plasma 17-alpha-OH-progesterone in female workers exposed to urban pollutants.

PubMed

Ciarrocca, M; Cerratti, D; Capozzella, A; Rosati, M V; Anzani, M F; Bernardini, A; Casale, T; Pimpinella, B; Tomei, G; Monti, C; Tomao, E; Tomei, F

2006-01-01

The aim of this study is to evaluate whether occupational exposure to urban pollutants could cause alteration in plasma 17-alpha-OH-P levels in female workers. After excluding the subjects with the principal confounding factors, traffic police and controls were matched by age, working life, age of menarche, menstrual cycle day, BMI, drinking habits, habitual consumption of soy and Italian coffee. 68 traffic police and 82 controls (7th day; follicular phase of the ovarian cycle), 37 traffic police and 20 controls (21st day; lutheal phase of the ovarian cycle) were included in the study and matched for the above mentioned variables. In follicular and lutheal phase of ovarian cycle, 17-alpha-OH-P mean levels and the distribution of 17-alpha-OH-P values were significantly higher in traffic police vs. controls. A higher instance of mental health disorders in traffic police vs. controls was found, although the difference was not significant. Considering that the potential confounding effect of extraneous factors was controlled by restricting the study population and by matching traffic police vs. controls on the above mentioned variables, our results suggest that occupational exposure to urban pollutants may alter plasma 17-alpha-OH-P concentrations. 17-alpha-OH-P could be used in an occupational setting as an early biomarker of exposure to urban pollutants, valuable for a group, even before the onset of related pathologies.

Assessment and management of human health risk from toxic metals and polycyclic aromatic hydrocarbons in urban stormwater arising from anthropogenic activities and traffic congestion.

PubMed

Ma, Yukun; Liu, An; Egodawatta, Prasanna; McGree, James; Goonetilleke, Ashantha

2017-02-01

Toxic metals (TMs) and polycyclic aromatic hydrocarbons (PAHs) in urban stormwater pose risk to human health, thereby constraining its reuse potential. Based on the hypothesis that stormwater quality is primarily influenced by anthropogenic activities and traffic congestion, the primary focus of the research study was to analyse the impacts on human health risk from TMs and PAHs in urban stormwater and thereby develop a quantitative risk assessment model. The study found that anthropogenic activities and traffic congestion exert influence on the risk posed by TMs and PAHs in stormwater from commercial and residential areas. Motor vehicle related businesses (FVS) and traffic congestion (TC) were identified as two parameters which need to be included as independent variables to improve the model. Based on the study outcomes, approaches for mitigating the risk associated with TMs and PAHs in urban stormwater are discussed. Additionally, a roadmap is presented for the assessment and management of the risk arising from these pollutants. The study outcomes are expected to contribute to reducing the human health risk associated urban stormwater pollution and thereby enhance its reuse potential. Copyright © 2016 Elsevier B.V. All rights reserved.

The Loss of Efficiency Caused by Agents’ Uncoordinated Routing in Transport Networks

PubMed Central

Wang, Junjie; Wang, Pu

2014-01-01

Large-scale daily commuting data were combined with detailed geographical information system (GIS) data to analyze the loss of transport efficiency caused by drivers’ uncoordinated routing in urban road networks. We used Price of Anarchy (POA) to quantify the loss of transport efficiency and found that both volume and distribution of human mobility demand determine the POA. In order to reduce POA, a small number of highways require considerable decreases in traffic, and their neighboring arterial roads need to attract more traffic. The magnitude of the adjustment in traffic flow can be estimated using the fundamental measure traffic flow only, which is widely available and easy to collect. Surprisingly, the most congested roads or the roads with largest traffic flow were not those requiring the most reduction of traffic. This study can offer guidance for the optimal control of urban traffic and facilitate improvements in the efficiency of transport networks. PMID:25349995

Traffic and nucleation events as main sources of ultrafine particles in high-insolation developed world cities

NASA Astrophysics Data System (ADS)

Brines, M.; Dall'Osto, M.; Beddows, D. C. S.; Harrison, R. M.; Gómez-Moreno, F.; Núñez, L.; Artíñano, B.; Costabile, F.; Gobbi, G. P.; Salimi, F.; Morawska, L.; Sioutas, C.; Querol, X.

2015-05-01

Road traffic emissions are often considered the main source of ultrafine particles (UFP, diameter smaller than 100 nm) in urban environments. However, recent studies worldwide have shown that - in high-insolation urban regions at least - new particle formation events can also contribute to UFP. In order to quantify such events we systematically studied three cities located in predominantly sunny environments: Barcelona (Spain), Madrid (Spain) and Brisbane (Australia). Three long-term data sets (1-2 years) of fine and ultrafine particle number size distributions (measured by SMPS, Scanning Mobility Particle Sizer) were analysed. Compared to total particle number concentrations, aerosol size distributions offer far more information on the type, origin and atmospheric evolution of the particles. By applying k-means clustering analysis, we categorized the collected aerosol size distributions into three main categories: "Traffic" (prevailing 44-63% of the time), "Nucleation" (14-19%) and "Background pollution and Specific cases" (7-22%). Measurements from Rome (Italy) and Los Angeles (USA) were also included to complement the study. The daily variation of the average UFP concentrations for a typical nucleation day at each site revealed a similar pattern for all cities, with three distinct particle bursts. A morning and an evening spike reflected traffic rush hours, whereas a third one at midday showed nucleation events. The photochemically nucleated particles' burst lasted 1-4 h, reaching sizes of 30-40 nm. On average, the occurrence of particle size spectra dominated by nucleation events was 16% of the time, showing the importance of this process as a source of UFP in urban environments exposed to high solar radiation. Nucleation events lasting for 2 h or more occurred on 55% of the days, this extending to > 4 h in 28% of the days, demonstrating that atmospheric conditions in urban environments are not favourable to the growth of photochemically nucleated particles. In summary, although traffic remains the main source of UFP in urban areas, in developed countries with high insolation urban nucleation events are also a main source of UFP. If traffic-related particle concentrations are reduced in the future, nucleation events will likely increase in urban areas, due to the reduced urban condensation sinks.

Incorporating real-time traffic and weather data to explore road accident likelihood and severity in urban arterials.

PubMed

Theofilatos, Athanasios

2017-06-01

The effective treatment of road accidents and thus the enhancement of road safety is a major concern to societies due to the losses in human lives and the economic and social costs. The investigation of road accident likelihood and severity by utilizing real-time traffic and weather data has recently received significant attention by researchers. However, collected data mainly stem from freeways and expressways. Consequently, the aim of the present paper is to add to the current knowledge by investigating accident likelihood and severity by exploiting real-time traffic and weather data collected from urban arterials in Athens, Greece. Random Forests (RF) are firstly applied for preliminary analysis purposes. More specifically, it is aimed to rank candidate variables according to their relevant importance and provide a first insight on the potential significant variables. Then, Bayesian logistic regression as well finite mixture and mixed effects logit models are applied to further explore factors associated with accident likelihood and severity respectively. Regarding accident likelihood, the Bayesian logistic regression showed that variations in traffic significantly influence accident occurrence. On the other hand, accident severity analysis revealed a generally mixed influence of traffic variations on accident severity, although international literature states that traffic variations increase severity. Lastly, weather parameters did not find to have a direct influence on accident likelihood or severity. The study added to the current knowledge by incorporating real-time traffic and weather data from urban arterials to investigate accident occurrence and accident severity mechanisms. The identification of risk factors can lead to the development of effective traffic management strategies to reduce accident occurrence and severity of injuries in urban arterials. Copyright © 2017 Elsevier Ltd and National Safety Council. All rights reserved.

Influence of local parameters on the dispersion of traffic-related pollutants within street canyons

NASA Astrophysics Data System (ADS)

Karra, Styliani; Malki-Epshtein, Liora; Martin Hyde Collaboration

2011-11-01

Ventilation within urban cities and street canyons and the associated air quality is a problem of increasing interest in the last decades. It is important for to minimise exposure of the population to traffic-related pollutants at street level. The residence time of pollutants within the street canyons depends on the meteorological conditions such as wind speed and direction, geometry layout and local parameters (position of traffic lane within the street). An experimental study was carried out to investigate the influence of traffic lane position on the dispersion of traffic-related pollutants within different street canyons geometries: symmetrical (equal building heights on both sides of the street), non-symmetrical (uniform building heights but lower on one side of the street) and heterogeneous (non-uniform building heights on both sides of the street) under constant meteorological conditions. Laboratory experiments were carried out within a water channel and simultaneous measurements of velocity field and concentration scalar levels within and above the street canyons using PIV and PLIF techniques. Traffic -related emissions were simulated using a line emission source. Two positions were examined for all street geometries: line emission source was placed in the centre of the street canyon; line emission source was placed off the centre of the street. TSI Incorporated.

A study on traffic noise of two campuses of University, Balasore, India.

PubMed

Goswami, Shreerup; Nayak, Subrata Kumar; Pradhan, Akula Chandra; Dey, Surjendu Kumar

2011-01-01

Noise pollution is a significant environmental problem in many rapidly urbanizing areas of Orissa, India. Transportation sector is one of the major contributors to noise in these areas. The present study is an attempt to estimate traffic noise pollution at five places on the way from Vyasa Vihar Campus to Gyan Vigyan Vihar Campus of Fakir Mohan University, Balasore, Orissa. The sources of noise at the studied sites are predominantly attributable to motor vehicular traffic. The noise levels of all the five locations were found to be beyond permissible limit during the day time. The contributions of different types of vehicles to environmental noise were found to ranging from 70.4-94.2, 79.0-96.1, 77.8-110.2, 70.8-90.3, 71.0-87.5, 71.1-84.4, 72.5-86.9 and 74.0-85.4 dB (A) by cargo carrying Trucks, Tractors, Dumpers, Town Buses, Motor cycles, Bolero/Trucker, Pick up and Tempo respectively. The contributions of individual vehicles towards noise pollution were found to be more than the road traffic noise-limit i.e., 70 dB (A). On certain local inhabitants interviewed, the impact of noise was observed in the forms of alterations in their physical, psychological and personal aspects. This study warrants attention from all sections of people to deal with the problem of noise pollution.

Characterizing local traffic contributions to particulate air pollution in street canyons using mobile monitoring techniques

NASA Astrophysics Data System (ADS)

Zwack, Leonard M.; Paciorek, Christopher J.; Spengler, John D.; Levy, Jonathan I.

2011-05-01

Traffic within urban street canyons can contribute significantly to ambient concentrations of particulate air pollution. In these settings, it is challenging to separate within-canyon source contributions from urban and regional background concentrations given the highly variable and complex emissions and dispersion characteristics. In this study, we used continuous mobile monitoring of traffic-related particulate air pollutants to assess the contribution to concentrations, above background, of traffic in the street canyons of midtown Manhattan. Concentrations of both ultrafine particles (UFP) and fine particles (PM 2.5) were measured at street level using portable instruments. Statistical modeling techniques accounting for autocorrelation were used to investigate the presence of spatial heterogeneity of pollutant concentrations as well as to quantify the contribution of within-canyon traffic sources. Measurements were also made within Central Park, to examine the impact of offsets from major roadways in this urban environment. On average, an approximate 11% increase in concentrations of UFP and 8% increase in concentrations of PM 2.5 over urban background was estimated during high-traffic periods in street canyons as opposed to low traffic periods. Estimates were 8% and 5%, respectively, after accounting for temporal autocorrelation. Within Central Park, concentrations were 40% higher than background (5% after accounting for temporal autocorrelation) within the first 100 m from the nearest roadway for UFP, with a smaller but statistically significant increase for PM 2.5. Our findings demonstrate the viability of a mobile monitoring protocol coupled with spatiotemporal modeling techniques in characterizing local source contributions in a setting with street canyons.

Design mechanic generator under speed bumper to support electricity recourse for urban traffic light

NASA Astrophysics Data System (ADS)

Sabri, M.; Lauzuardy, Jason; Syam, Bustami

2018-03-01

The electrical energy needs for the traffic lights in some cities of developing countries cannot be achieved continuously due to limited capacity and interruption of electricity distribution, the main power plant. This issues can lead to congestion at the crossroads. To overcome the problem of street chaos due to power failure, we can cultivate to provide electrical energy from other sources such as using the bumper to generate kinetic energy, which can be converted into electrical energy. This study designed a generator mechanic that will be mounted on the bumper construction to generate electricity for the purposes of traffic lights at the crossroads. The Mechanical generator is composed of springs, levers, sprockets, chains, flywheel and customize power generator. Through the rotation of the flywheel, we can earned 9 Volt DC voltage and electrical current of 5.89 Ampere. This achievement can be used to charge the accumulator which can be used to power the traffic lights, and to charge the accumulator capacity of 6 Ah, the generator works in the charging time for 1.01 hours.

Noise abatement and traffic safety: The trade-off of quieter engines and pavements on vehicle detection.

PubMed

Mendonça, C; Freitas, E; Ferreira, J P; Raimundo, I D; Santos, J A

2013-03-01

Road traffic sounds are a major source of noise pollution in urban areas. But recent developments such as low noise pavements and hybrid/electric engine vehicles cast an optimistic outlook over such an environmental problem. However, it can be argued that engine, tire, and road noise could be relevant sources of information to avoid road traffic conflicts and accidents. In this paper, we analyze the potential trade-offs of traffic-noise abatement approaches in an experimental study, focusing for the first time on the impact and interaction of relevant factors such as pavement type, vehicle type, listener's age, and background noise, on vehicle detection levels. Results reveal that vehicle and pavement type significantly affect vehicle detection. Age is a significant factor, as both younger and older people exhibit lower detection levels of incoming vehicles. Low noise pavements combined with all-electric and hybrid vehicles might pose a severe threat to the safety of vulnerable road users. All factors interact simultaneously, and vehicle detection is best predicted by the loudness signal-to-noise ratio. Copyright © 2012 Elsevier Ltd. All rights reserved.

The Impact of the Thai Motorcycle Transition on Road Traffic Injury: Thai Cohort Study Results

PubMed Central

Berecki-Gisolf, Janneke; Yiengprugsawan, Vasoontara; Kelly, Matthew; McClure, Roderick; Seubsman, Sam-ang; Sleigh, Adrian

2015-01-01

Objectives The aim of this study was to investigate the impact of motorcycle to car transitioning and urbanisation on traffic injury rates in Thailand. Design Analysis of two consecutive surveys of a large national cohort study. Setting Thailand. Participants The data derived from 57,154 Thai Cohort Study (TCS) participants who provided relevant data on both the 2005 and 2009 surveys. Primary and secondary outcome measures Motorcycle and car traffic crash injury self-reported in 2009, with twelve months’ recall. Results In 2009, 5608(10%) participants reported a traffic crash injury. Most crashes involved a motorcycle (74%). Car access increased and motorcycle use decreased between 2005 and 2009. Among those who used a motorcycle at both time points, traffic injury incidence was 2.8 times greater compared to those who did not use a motorcycle at either time point. Multivariable logistic regression models were used to test longitudinal and cross sectional factors associated with traffic crash injury: in the adjusted model, cars were negatively and motorcycles positively associated with injury. Living in an urban area was not injury protective in the adjusted model of traffic crash injury. Conclusions Ongoing urbanisation in Thailand can be expected to lead to further reductions in road traffic injuries based on transition from motorcycles to cars in urban areas. Cities, however, do not provide an intrinsically safer traffic environment. To accommodate a safe transition to car use in Thailand, traffic infrastructural changes anticipating the growing car density in urban areas is warranted. PMID:25826214

Understanding the topological characteristics and flow complexity of urban traffic congestion

NASA Astrophysics Data System (ADS)

Wen, Tzai-Hung; Chin, Wei-Chien-Benny; Lai, Pei-Chun

2017-05-01

For a growing number of developing cities, the capacities of streets cannot meet the rapidly growing demand of cars, causing traffic congestion. Understanding the spatial-temporal process of traffic flow and detecting traffic congestion are important issues associated with developing sustainable urban policies to resolve congestion. Therefore, the objective of this study is to propose a flow-based ranking algorithm for investigating traffic demands in terms of the attractiveness of street segments and flow complexity of the street network based on turning probability. Our results show that, by analyzing the topological characteristics of streets and volume data for a small fraction of street segments in Taipei City, the most congested segments of the city were identified successfully. The identified congested segments are significantly close to the potential congestion zones, including the officially announced most congested streets, the segments with slow moving speeds at rush hours, and the areas near significant landmarks. The identified congested segments also captured congestion-prone areas concentrated in the business districts and industrial areas of the city. Identifying the topological characteristics and flow complexity of traffic congestion provides network topological insights for sustainable urban planning, and these characteristics can be used to further understand congestion propagation.

[Traffic accidents: a health problem in primary care].

PubMed

Blanquer, J J; Rapa, M; Melchor, A; Jiménez, T; Adam, A; Mulet, M J

1993-09-15

To discover the prevalence and most relevant epidemiological characteristics of the victims of traffic accidents which occur in our health area. Hospital Casualty department (HC), Health area 19, Alcoy. This was an observational, crossover study, based on the collection of data from all those patients who had been brought into the HC for attention because of a traffic accident and who were attended between October 1, 1990 and September 31, 1991. During the study period a total of 1,111 traffic accident victims were attended. Their average age was 26.62 (SD +/- 15.95), with 69.6% being men and 30.2% women. 60.7% of the victims were attended on non-working days or the eve of a non-working day. 44.5% of those involved in accidents were in four-wheeled vehicles; 40% on two-wheeled vehicles and 11.1% of the victims were pedestrians. Injuries were light in 73.3% of cases; moderate in 15.9% and in the other 8.8% serious, grave or critical. 43.7% of the total had the accident in an urban area and 40.9% on the open road. The high prevalence of victims of accidents (8.3 per 1000 inhabitants) observed in our health area can be explained by the type of study. It is vital to obtain valid information of the real importance of this health problem. The primary care doctor must take preventive action concerning traffic accidents: a) through full studies of traffic accident levels among primary care centre users; b) primary preventive action, through the spreading of information on norms of safety; and c) secondary and tertiary prevention, by means of effective and efficacious outpatient emergency measures, as well as a thorough rehabilitation of accident victims.

A method to estimate spatiotemporal air quality in an urban traffic corridor.

PubMed

Singh, Nongthombam Premananda; Gokhale, Sharad

2015-12-15

Air quality exposure assessment using personal exposure sampling or direct measurement of spatiotemporal air pollutant concentrations has difficulty and limitations. Most statistical methods used for estimating spatiotemporal air quality do not account for the source characteristics (e.g. emissions). In this study, a prediction method, based on the lognormal probability distribution of hourly-average-spatial concentrations of carbon monoxide (CO) obtained by a CALINE4 model, has been developed and validated in an urban traffic corridor. The data on CO concentrations were collected at three locations and traffic and meteorology within the urban traffic corridor.(1) The method has been developed with the data of one location and validated at other two locations. The method estimated the CO concentrations reasonably well (correlation coefficient, r≥0.96). Later, the method has been applied to estimate the probability of occurrence [P(C≥Cstd] of the spatial CO concentrations in the corridor. The results have been promising and, therefore, may be useful to quantifying spatiotemporal air quality within an urban area. Copyright © 2015 Elsevier B.V. All rights reserved.

Characterizing the influence of transportation infrastructure on Emergency Medical Services (EMS) in urban area-A case study of Seoul, South Korea.

PubMed

Cho, Jungwoo; You, Myoungsoon; Yoon, Yoonjin

2017-01-01

In highly urbanized area where traffic condition fluctuates constantly, transportation infrastructure is one of the major contributing factors to Emergency Medical Service (EMS) availability and patient outcome. In this paper, we assess the impact of traffic fluctuation to the EMS first response availability in urban area, by evaluating the k-minute coverage under 21 traffic scenarios. The set of traffic scenarios represents the time-of-day and day-of-week effects, and is generated by combining road link speed information from multiple historical speed databases. In addition to the k-minute area coverage calculation, the k-minute population coverage is also evaluated for every 100m by 100m grid that partitions the case study area of Seoul, South Korea. In the baseline case of traveling at the speed limit, both the area and population coverage reached nearly 100% when compared to the five-minute travel time national target. Employing the proposed LoST (Loss of Serviceability due to Traffic) index, which measures coverage reduction in percentage compared to the baseline case, we find that the citywide average LoST for area and population coverage are similar at 34.2% and 33.8%. However, district-wise analysis reveals that such reduction varies significantly by district, and the magnitude of area and population coverage reduction is not always proportional. We conclude that the effect of traffic variation is significant to successful urban EMS first response performance, and regional variation is evident among local districts. Complexity in the urban environment requires a more adaptive approach in public health resource management and EMS performance target determination.

Urban pavement surface temperature. Comparison of numerical and statistical approach

NASA Astrophysics Data System (ADS)

Marchetti, Mario; Khalifa, Abderrahmen; Bues, Michel; Bouilloud, Ludovic; Martin, Eric; Chancibaut, Katia

2015-04-01

The forecast of pavement surface temperature is very specific in the context of urban winter maintenance. to manage snow plowing and salting of roads. Such forecast mainly relies on numerical models based on a description of the energy balance between the atmosphere, the buildings and the pavement, with a canyon configuration. Nevertheless, there is a specific need in the physical description and the numerical implementation of the traffic in the energy flux balance. This traffic was originally considered as a constant. Many changes were performed in a numerical model to describe as accurately as possible the traffic effects on this urban energy balance, such as tires friction, pavement-air exchange coefficient, and infrared flux neat balance. Some experiments based on infrared thermography and radiometry were then conducted to quantify the effect fo traffic on urban pavement surface. Based on meteorological data, corresponding pavement temperature forecast were calculated and were compared with fiels measurements. Results indicated a good agreement between the forecast from the numerical model based on this energy balance approach. A complementary forecast approach based on principal component analysis (PCA) and partial least-square regression (PLS) was also developed, with data from thermal mapping usng infrared radiometry. The forecast of pavement surface temperature with air temperature was obtained in the specific case of urban configurtation, and considering traffic into measurements used for the statistical analysis. A comparison between results from the numerical model based on energy balance, and PCA/PLS was then conducted, indicating the advantages and limits of each approach.

How healthy is urban horticulture in high traffic areas? Trace metal concentrations in vegetable crops from plantings within inner city neighbourhoods in Berlin, Germany.

PubMed

Säumel, Ina; Kotsyuk, Iryna; Hölscher, Marie; Lenkereit, Claudia; Weber, Frauke; Kowarik, Ingo

2012-06-01

Food production by urban dwellers is of growing importance in developing and developed countries. Urban horticulture is associated with health risks as crops in urban settings are generally exposed to higher levels of pollutants than those in rural areas. We determined the concentration of trace metals in the biomass of different horticultural crops grown in the inner city of Berlin, Germany, and analysed how the local setting shaped the concentration patterns. We revealed significant differences in trace metal concentrations depending on local traffic, crop species, planting style and building structures, but not on vegetable type. Higher overall traffic burden increased trace metal content in the biomass. The presence of buildings and large masses of vegetation as barriers between crops and roads reduced trace metal content in the biomass. Based on this we discuss consequences for urban horticulture, risk assessment, and planting and monitoring guidelines for cultivation and consumption of crops. Copyright © 2012 Elsevier Ltd. All rights reserved.

Opportunities for Environmental Noise Mapping in Saudi Arabia: A Case of Traffic Noise Annoyance in an Urban Area in Jeddah City

PubMed Central

Zytoon, Mohamed A.

2016-01-01

As the traffic and other environmental noise generating activities are growing in The Kingdom of Saudi Arabia (KSA), adverse health and other impacts are expected to develop. The management of such problem involves many actions, of which noise mapping has been proven to be a helpful approach. The objective of the current study was to test the adequacy of the available data in KSA municipalities for generating urban noise maps and to verify the applicability of available environmental noise mapping and noise annoyance models for KSA. Therefore, noise maps were produced for Al-Fayha District in Jeddah City, KSA using commercially available noise mapping software and applying the French national computation method “NMPB” for traffic noise. Most of the data required for traffic noise prediction and annoyance analysis were available, either in the Municipality GIS department or in other governmental authorities. The predicted noise levels during the three time periods, i.e., daytime, evening, and nighttime, were found higher than the maximum recommended levels established in KSA environmental noise standards. Annoyance analysis revealed that high percentages of the District inhabitants were highly annoyed, depending on the type of planning zone and period of interest. These results reflect the urgent need to consider environmental noise reduction in KSA national plans. The accuracy of the predicted noise levels and the availability of most of the necessary data should encourage further studies on the use of noise mapping as part of noise reduction plans. PMID:27187438

Traveler oriented traffic performance metrics using real time traffic data from the Midtown-in-Motion (MIM) project in Manhattan, NY.

DOT National Transportation Integrated Search

2013-10-01

In a congested urban street network the average traffic speed is an inadequate metric for measuring : speed changes that drivers can perceive from changes in traffic control strategies. : A driver oriented metric is needed. Stop frequency distrib...

Simulating the impacts of on-street vehicle parking on traffic operations on urban streets using cellular automation

NASA Astrophysics Data System (ADS)

Chen, Jingxu; Li, Zhibin; Jiang, Hang; Zhu, Senlai; Wang, Wei

2017-02-01

In recent years, many bicycle lanes on urban streets are replaced with vehicle parking places. Spaces for bicycle riding are reduced, resulting in changes in bicycle and vehicle operational features. The objective of this study is to estimate the impacts of on-street parking on heterogeneous traffic operation on urban streets. A cellular automaton (CA) model is developed and calibrated to simulate bicycle lane-changing on streets with on-street parking. Two types of street segments with different bicycle lane width are considered. From the simulation, two types of conflicts between bicycles and vehicles are identified which are frictional conflicts and blocking conflicts. Factors affecting the frequency of conflicts are also identified. Based on the results, vehicle delay is estimated for various traffic situations considering the range of occupancy levels for on-street parking. Later, a numerical network example is analyzed to estimate the network impact of on-street parking on traffic assignment and operation. Findings of the study are helpful to policies and design regarding on-street vehicle parking to improve the efficiency of traffic operations.

Traffic evacuation time under nonhomogeneous conditions.

PubMed

Fazio, Joseph; Shetkar, Rohan; Mathew, Tom V

2017-06-01

During many manmade and natural crises such as terrorist threats, floods, hazardous chemical and gas leaks, emergency personnel need to estimate the time in which people can evacuate from the affected urban area. Knowing an estimated evacuation time for a given crisis, emergency personnel can plan and prepare accordingly with the understanding that the actual evacuation time will take longer. Given the urban area to be evacuated, street widths exiting the area's perimeter, the area's population density, average vehicle occupancy, transport mode share and crawl speed, an estimation of traffic evacuation time can be derived. Peak-hour traffic data collected at three, midblock, Mumbai sites of varying geometric features and traffic composition were used in calibrating a model that estimates peak-hour traffic flow rates. Model validation revealed a correlation coefficient of +0.98 between observed and predicted peak-hour flow rates. A methodology is developed that estimates traffic evacuation time using the model.

Influence of Environmental Pollution on Leaf Properties of Urban Plane Trees, Platanus orientalis L.

PubMed Central

Pourkhabbaz, Alireza; Rastin, Nayerah; Olbrich, Andrea; Langenfeld-Heyser, Rosemarie

2010-01-01

To investigate whether leaves of plane trees (Platanus orientalis) are damaged by traffic pollution, trees from a megacity (Mashhad, Iran) and a rural area were investigated. Soil and air from the urban centre showed enrichment of several toxic elements, but only lead was enriched in leaves. Leaf size and stomata density were lower at the urban site. At the urban site leaf surfaces were heavily loaded by dust particles but the stomata were not occluded; the cuticle was thinner; other anatomical properties were unaffected suggesting that plane trees can cope with traffic exhaust in megacities. PMID:20577871

Influence of environmental pollution on leaf properties of urban plane trees, Platanus orientalis L.

PubMed

Pourkhabbaz, Alireza; Rastin, Nayerah; Olbrich, Andrea; Langenfeld-Heyser, Rosemarie; Polle, Andrea

2010-09-01

To investigate whether leaves of plane trees (Platanus orientalis) are damaged by traffic pollution, trees from a megacity (Mashhad, Iran) and a rural area were investigated. Soil and air from the urban centre showed enrichment of several toxic elements, but only lead was enriched in leaves. Leaf size and stomata density were lower at the urban site. At the urban site leaf surfaces were heavily loaded by dust particles but the stomata were not occluded; the cuticle was thinner; other anatomical properties were unaffected suggesting that plane trees can cope with traffic exhaust in megacities.

A video-based real-time adaptive vehicle-counting system for urban roads.

PubMed

Liu, Fei; Zeng, Zhiyuan; Jiang, Rong

2017-01-01

In developing nations, many expanding cities are facing challenges that result from the overwhelming numbers of people and vehicles. Collecting real-time, reliable and precise traffic flow information is crucial for urban traffic management. The main purpose of this paper is to develop an adaptive model that can assess the real-time vehicle counts on urban roads using computer vision technologies. This paper proposes an automatic real-time background update algorithm for vehicle detection and an adaptive pattern for vehicle counting based on the virtual loop and detection line methods. In addition, a new robust detection method is introduced to monitor the real-time traffic congestion state of road section. A prototype system has been developed and installed on an urban road for testing. The results show that the system is robust, with a real-time counting accuracy exceeding 99% in most field scenarios.

A video-based real-time adaptive vehicle-counting system for urban roads

PubMed Central

2017-01-01

In developing nations, many expanding cities are facing challenges that result from the overwhelming numbers of people and vehicles. Collecting real-time, reliable and precise traffic flow information is crucial for urban traffic management. The main purpose of this paper is to develop an adaptive model that can assess the real-time vehicle counts on urban roads using computer vision technologies. This paper proposes an automatic real-time background update algorithm for vehicle detection and an adaptive pattern for vehicle counting based on the virtual loop and detection line methods. In addition, a new robust detection method is introduced to monitor the real-time traffic congestion state of road section. A prototype system has been developed and installed on an urban road for testing. The results show that the system is robust, with a real-time counting accuracy exceeding 99% in most field scenarios. PMID:29135984

Establishing a link between vehicular PM sources and PM measurements in urban street canyons.

PubMed

Eisner, Alfred D; Richmond-Bryant, Jennifer; Wiener, Russell W; Hahn, Intaek; Drake-Richman, Zora E; Ellenson, William D

2009-12-01

The Brooklyn Traffic Real-Time Ambient Pollutant Penetration and Environmental Dispersion (B-TRAPPED) study, conducted in Brooklyn, NY, USA, in 2005, was designed with multiple goals in mind, two of which were contaminant source characterization and street canyon transport and dispersion monitoring. In the portion of the study described here, synchronized wind velocity and azimuth as well as particulate matter (PM) concentrations at multiple locations along 33rd Street were used to determine the feasibility of using traffic emissions in a complex urban topography as a sole tracer for studying urban contaminant transport. We demonstrate in this paper that it is possible to link downwind concentrations of contaminants in an urban street canyon to the vehicular traffic cycle using Eigen-frequency analysis. In addition, multivariable circular histograms are used to establish directional frequency maxima for wind velocity and contaminant concentration.

Relationship between road traffic noisescape and urban form in Hong Kong.

PubMed

Lam, Kin-Che; Ma, Weichun; Chan, Pak Kin; Hui, Wing Chi; Chung, King Lam; Chung, Yi-tak Teresa; Wong, Chun Yin; Lin, Hui

2013-12-01

This paper reports on a study which explored the possible relationship between road traffic noisescape and urban form in Hong Kong. A total of 212 residential complexes from 11 contrasting urban forms were sampled, and their noise levels assessed both at dwelling and neighbourhood scales by noise mapping. Its findings indicate that residential complexes with different urban forms have significantly different noisescape attributes. There is a strong correlation between the noise characteristics and morphological indicators at the dwelling scale. A less obstreperous noisescape is associated with urban forms with lower road and building densities, and with building arrangements which provide self-noise screening. These findings suggest that urban form is an influential determinant of the noisescape in the urban environment, and they point to the need to rethink the conventional approach to managing the urban acoustic environment.

A new bus lane on urban expressway with no-bay bus stop

NASA Astrophysics Data System (ADS)

Tian, Zhao; Jia, Limin

2016-01-01

The sharp increase in residents and vehicles causes heavy traffic pressure in many cities. To ease traffic congestion, it has been the common sense that we should develop public transit system. The priority of the bus appears particularly necessary with the rapid development of the public transport system. The bus lane is an important embodiment of the bus priority. Focusing on the problem of the unreasonable dedicated bus lane (DBL) under the lower ratio of buses, this paper proposed a new bus lane with limited physical length. And this bus lane can reduce the lane-changing conflict caused by the buses and cars running on roads without bus lanes. Based on the cellular automata (CA) traffic flow model and the lane-changing behavior of the vehicle including the optional lane-changing and the mandatory lane-changing, a three-lane traffic model with an isolated no-bay bus stop is proposed. The ordinary three-lane traffic without a bus lane and the cases of traffic with a DBL or the proposed bus lane are simulated, and the comparisons in the form of the fundamental diagrams are made among them. It is shown that the no-bay bus stop can act as a bottleneck on the traffic flow because of the mandatory lane-changing behavior. Under a certain ratio of the bus number to the total vehicles number, (1) the traffic with the proposed bus lane has less lane-changing conflict and can provide higher traffic capacity than the ordinary traffic without a bus lane, (2) compared with the DBL, the proposed bus lane is advantageous in easing congestion on the ordinary lanes when the traffic flow is high and can avoid unreasonable allocation of the road resources.

Managing the environmental impacts of land transport: integrating environmental analysis with urban planning.

PubMed

Irving, Paul; Moncrieff, Ian

2004-12-01

Ecological systems have limits or thresholds that vary by pollutant type, emissions sources and the sensitivity of a given location. Human health can also indicate sensitivity. Good environmental management requires any problem to be defined to obtain efficient and effective solutions. Cities are where transport activities, effects and resource management decisions are often most focussed. The New Zealand Ministry of Transport has developed two environmental management tools. The Vehicle Fleet Model (VFM) is a predictive database of the environmental performance of the New Zealand traffic fleet (and rail fleet). It calculates indices of local air quality, stormwater, and greenhouse gases emissions. The second is an analytical process based on Environmental Capacity Analysis (ECA). Information on local traffic is combined with environmental performance data from the Vehicle Fleet Model. This can be integrated within a live, geo-spatially defined analysis of the overall environmental effects within a defined local area. Variations in urban form and activity (traffic and other) that contribute to environmental effects can be tracked. This enables analysis of a range of mitigation strategies that may contribute, now or in the future, to maintaining environmental thresholds or meeting targets. A case study of the application of this approach was conducted within Waitakere City. The focus was on improving the understanding of the relative significance of stormwater contaminants derived from land transport.

Common Traffic Violations of Bus Drivers in Urban China: An Observational Study.

PubMed

Wang, Qiqi; Zhang, Wei; Yang, Rendong; Huang, Yuanxiu; Zhang, Lin; Ning, Peishan; Cheng, Xunjie; Schwebel, David C; Hu, Guoqing; Yao, Hongyan

2015-01-01

To report common traffic violations in bus drivers and the factors that influence those violations in urban China. We conducted an observational study to record three types of traffic violations among bus drivers in Changsha City, China: illegal stopping at bus stations, violating traffic light signals, and distracted driving. The behaviors of bus drivers on 32 routes (20% of bus routes in the city) were observed. A two-level Poisson regression examined factors that predicted bus driver violations. The incidence of illegal stopping at bus stations was 20.2%. Illegal stopping was less frequent on weekends, sunny days, and at stations with cameras, with adjusted incidence rate ratios (IRRs) of 0.81, 0.65 and 0.89, respectively. The incidence of violating traffic light signals was 2.2%, and was lower on cloudy than sunny days (adjusted IRR: 0.60). The incidence of distracted driving was 3.3%. The incidence of distracted driving was less common on cloudy days, rainy or snowy days, and foggy/windy/dusty days compared to sunny days, with adjusted IRRs of 0.54, 0.55 and 0.07, respectively. Traffic violations are common in bus drivers in urban China and they are associated with the date, weather, and presence of traffic cameras at bus station. Further studies are recommended to understand the behavioral mechanisms that may explain bus driver violations and to develop feasible prevention measures.

Investigation of schedules for traffic signal timing optimization.

DOT National Transportation Integrated Search

2005-01-01

Traffic signal optimization is recognized as one of the most cost-effective ways to improve urban mobility; however the extent of the benefits realized could significantly depend on how often traffic signal re-optimization occurs. Using a case study ...

Value of Information and Information Services

DOT National Transportation Integrated Search

1975-10-01

The report describes the salient features of the SCOT (Simulation of Corridor Traffic) model and a successful calibration and validation. SCOT is a computer model that may be applied to an urban traffic corridor and will simulate vehicular traffic on...

Traffic flow simulation for an urban freeway corridor

DOT National Transportation Integrated Search

1998-01-01

The objective of this paper is to develop a realistic and operational macroscopic traffic flow simulation model which requires relatively less data collection efforts. Such a model should be capable of delineating the dynamics of traffic flow created...

Investigating and improving pedestrian safety in an urban environment.

PubMed

Pollack, Keshia M; Gielen, Andrea C; Mohd Ismail, Mohd Nasir; Mitzner, Molly; Wu, Michael; Links, Jonathan M

2014-12-01

Prompted by a series of fatal and nonfatal pedestrian-vehicle collisions, university leadership from one urban institution collaborated with its academic injury research center to investigate traffic-related hazards facing pedestrians. This descriptive epidemiologic study used multiple data collection strategies to determine the burden of pedestrian injury in the target area. Data were collected in 2011 through a review of university crash reports from campus police; a systematic environmental audit and direct observations using a validated instrument and trained raters; and focus groups with faculty, students, and staff. Study findings were synthesized and evidence-informed recommendations were developed and disseminated to university leadership. Crash reports provided some indication of the risks on the streets adjacent to the campus. The environmental audit identified a lack of signage posting the speed limit, faded crosswalks, issues with traffic light and walk sign synchronization, and limited formal pedestrian crossings, which led to jaywalking. Focus groups participants described dangerous locations and times, signal controls and signage, enforcement of traffic laws, use of cell phones and iPods, and awareness of pedestrian safety. Recommendations to improve pedestrian safety were developed in accordance with the three E's of injury prevention (education, enforcement, and engineering), and along with plans for implementation and evaluation, were presented to university leadership. These results underscore the importance of using multiple methods to understand fully the problem, developing pragmatic recommendations that align with the three E's of injury prevention, and collaborating with leadership who have the authority to implement recommended injury countermeasures. These lessons are relevant for the many colleges and universities in urban settings where a majority of travel to offices, classrooms, and surrounding amenities are by foot.

Algorithms for constructing optimal paths and statistical analysis of passenger traffic

NASA Astrophysics Data System (ADS)

Trofimov, S. P.; Druzhinina, N. G.; Trofimova, O. G.

2018-01-01

Several existing information systems of urban passenger transport (UPT) are considered. Author’s UPT network model is presented. To a passenger a new service is offered that is the best path from one stop to another stop at a specified time. The algorithm and software implementation for finding the optimal path are presented. The algorithm uses the current UPT schedule. The article also describes the algorithm of statistical analysis of trip payments by the electronic E-cards. The algorithm allows obtaining the density of passenger traffic during the day. This density is independent of the network topology and UPT schedules. The resulting density of the traffic flow can solve a number of practical problems. In particular, the forecast for the overflow of passenger transport in the «rush» hours, the quantitative comparison of different topologies transport networks, constructing of the best UPT timetable. The efficiency of the proposed integrated approach is demonstrated by the example of the model town with arbitrary dimensions.

Urban compaction vs city sprawl: impact of road traffic on air quality in the greater Paris

NASA Astrophysics Data System (ADS)

Etuman Arthur, Elessa; Isabelle, Coll; Vincent, Viguie; Nicolas, Coulombel; Julie, Prud'homme

2017-04-01

Urban pollution remains a major sanitary and economic concern. In France, particulate pollution is known to cause 48,000 premature deaths every year (Santé Publique France, 2016), while the economic cost of air pollution reaches almost 25 billion euros per year (CGDD, 2012). In the Greater Paris, despite strengthened emission standards, restricted traffic areas, car-sharing and incentives for electric vehicle use, road transport plays a substantial role in the exposure of inhabitants to high levels of pollutants. In this context, urban planning could possibly constitute an innovative strategy to reduce emissions from road traffic, through its actions on transport demand, travel distances, modal shift (public transportation, cycling, walking...) or even proximity to emitters. We have developed a multi-scalar modeling of urban pollution by coupling an urban economic growth model NEDUM (CIRED), a model for urban mobility (LISA), a traffic emission model (LISA) and the CHIMERE Chemistry-Transport model (CTM) for air quality simulation (LISA). The innovative aspect of this modeling system is to integrate into a classic CTM the mechanisms underlying the dynamics of an urban system. This way, we establish a quantitative and comprehensive link between a given urban scenario, the associated public and individual transport matrix, and local air quality. We then make it possible to highlight the levers of energy consumption reductions inside compact or sprawled cities. We have been working on the Ile de France region (centered on the Paris agglomeration) which relies on a broad urban structure of megacity, a high density of housing and an expanding urban peripheral zone, clearly raising the issue of transport demand, mobility and traffic congestion. Two scenarios, considering opposite urban development policies from the 1960s to 2010, have been simulated over the whole modelling chain. The first one promotes a dense and compact city while the second favors city spread, though restricted by a green belt. In our results, we compare the local air quality simulated in these scenarios with our reference situation (the current 2010 situation). The spreading or densification of the city contribute a little to the air quality and therefore a reflection on a real mix of the urban canvas is probably an influencing factor for the reduction of the motorized mobility. We should also consider more advanced scenarios (in the course of production) for the reduction of individual transport like encouraging car-pooling, which has a maximum daily trip reduction potential of 16% in urban areas (CGDD, 2014).

Mobile phone tracking: in support of modelling traffic-related air pollution contribution to individual exposure and its implications for public health impact assessment.

PubMed

Liu, Hai-Ying; Skjetne, Erik; Kobernus, Mike

2013-11-04

We propose a new approach to assess the impact of traffic-related air pollution on public health by mapping personal trajectories using mobile phone tracking technology in an urban environment. Although this approach is not based on any empirical studies, we believe that this method has great potential and deserves serious attention. Mobile phone tracking technology makes it feasible to generate millions of personal trajectories and thereby cover a large fraction of an urban population. Through analysis, personal trajectories are not only associated to persons, but it can also be associated with vehicles, vehicle type, vehicle speed, vehicle emission rates, and sources of vehicle emissions. Pollution levels can be estimated by dispersion models from calculated traffic emissions. Traffic pollution exposure to individuals can be estimated based on the exposure along the individual human trajectories in the estimated pollution concentration fields by utilizing modelling tools. By data integration, one may identify trajectory patterns of particularly exposed human groups. The approach of personal trajectories may open a new paradigm in understanding urban dynamics and new perspectives in population-wide empirical public health research. This new approach can be further applied to individual commuter route planning, land use planning, urban traffic network planning, and used by authorities to formulate air pollution mitigation policies and regulations.

[Emission Characteristics of Vehicle Exhaust in Beijing Based on Actual Traffic Flow Information].

PubMed

Fan, Shou-bin; Tian, Ling-di; Zhang, Dong-xu; Qu, Song

2015-08-01

The basic data of traffic volume, vehicle type constitute and speed on road networks in Beijing was obtained fly modei simulation and field survey. Based on actual traffic flow information and. emission factors data with temporal and spatial distribution features, emission inventory of motor vehicle exhaust in Beijing was built on the ArcGIS platform, meanwhile, the actual road emission characteristics and spatial distribution of the pollutant emissions were analyzed. The results showed that the proportion of passenger car was higher than 89% on each type of road in the urban, and the proportion of passenger car was the highest in suburban roads as well while the pickup truck, medium truck, heavy truck, motorbus, tractor and motorcycle also occupied a certain proportion. There was a positive correlation between the pollutant emission intensity and traffic volume, and the emission intensity was generally higher in daytime than nighttime, but the diurnal variation trend of PM emission was not clear for suburban roads and the emission intensity was higher in nighttime than daytime for highway. The emission intensities in urban area, south, southeast and northeast areas near urban were higher than those in the western and northern mountainous areas with lower density of road network. The ring roads in urban and highways in suburban had higher emission intensity because of the heavy traffic volume.

Mobile phone tracking: in support of modelling traffic-related air pollution contribution to individual exposure and its implications for public health impact assessment

PubMed Central

2013-01-01

We propose a new approach to assess the impact of traffic-related air pollution on public health by mapping personal trajectories using mobile phone tracking technology in an urban environment. Although this approach is not based on any empirical studies, we believe that this method has great potential and deserves serious attention. Mobile phone tracking technology makes it feasible to generate millions of personal trajectories and thereby cover a large fraction of an urban population. Through analysis, personal trajectories are not only associated to persons, but it can also be associated with vehicles, vehicle type, vehicle speed, vehicle emission rates, and sources of vehicle emissions. Pollution levels can be estimated by dispersion models from calculated traffic emissions. Traffic pollution exposure to individuals can be estimated based on the exposure along the individual human trajectories in the estimated pollution concentration fields by utilizing modelling tools. By data integration, one may identify trajectory patterns of particularly exposed human groups. The approach of personal trajectories may open a new paradigm in understanding urban dynamics and new perspectives in population-wide empirical public health research. This new approach can be further applied to individual commuter route planning, land use planning, urban traffic network planning, and used by authorities to formulate air pollution mitigation policies and regulations. PMID:24188173

Participatory measurements of individual exposure to air pollution in urban areas

NASA Astrophysics Data System (ADS)

Madelin, Malika; Duché, Sarah; Dupuis, Vincent

2016-04-01

Air pollution is a major environmental issue in urban areas. Chronic and high concentration exposure presents a health risk with cardiovascular and respiratory problems and longer term nervous, carcinogenic and endocrine problems. In addition to the estimations based on simulations of both background and regional pollution and of the pollution induced by the traffic, knowing exposure of each individual is a key issue. This exposure reflects the high variability of pollution at fine spatial and time scales, according to the proximity of emission sources and the urban morphology outside. The emergence of citizen science and the progress of miniaturized electronics, low-cost and accessible to (almost) everyone, offers new opportunities for the monitoring of air pollution, but also for the citizens' awareness of their individual exposure to air pollution. In this communication, we propose to present a participatory research project 'What is your air?' (project funded by the Île-de-France region), which aims at raising awareness on the theme of air quality, its monitoring with sensors assembled in a FabLab workshop and an online participatory mapping. Beyond the discussion on technical choices, the stages of manufacture or the sensor calibration procedures, we discuss the measurements made, in this case the fine particle concentration measurements, which are dated and georeferenced (communication via a mobile phone). They show high variability between the measurements (in part linked to the substrates, land use, traffic) and low daily contrasts. In addition to the analysis of the measurements and their comparison with the official data, we also discuss the choice of representation of information, including mapping, and therefore the message about pollution to communicate.

Outside and inside noise exposure in urban and suburban areas

Treesearch

Dwight E. Bishop; Myles A. Simpson

1977-01-01

In urban and suburban areas of the United States (away from major airports), the outdoor noise environment usually depends strongly on local vehicular traffic. By relating traffic flow to population density, a model of outdoor noise exposure has been developed for estimating the cumulative 24-hour noise exposure based upon the population density of the area. This noise...

Development of «Park-and-Ride» system as a tool for sustainable access control managing

NASA Astrophysics Data System (ADS)

Danilina, Nina; Vlasov, Denis

2017-10-01

Large cities, whereby people use private transport, are facing the same challenges related to traffic congestion, reliability of public transportation and parking demand. Managing urban traffic and transport has become the most relevant police in transport planning. The article deals with the potential for further implementation in Russian Federation of «Park-and- Ride» recognized as an essential part of the overall transport and parking offer and successful planning tool to reducing congestion for any urban area around the world. The studies have been carried out in Moscow acknowledged as the city core of Moscow agglomeration — the largest and most populous in Russia. The research aims to support for the development of «Park-and-Ride» system applying the methodical approach adapted by the authors for the study to make it relevant for cities. A three-steps access control is offered to reduce private cars use in the city center. The results of the studies shows that such traffic management tool can help successfully in balancing the traffic demand and supply and, consequently, in resolving transport congestion and the number of coherent social, urban and economic challenges addressed to the sustainable development of urban areas.

Influence of urban vegetation on air pollution and noise exposure - A case study in Gothenburg, Sweden.

PubMed

Klingberg, Jenny; Broberg, Malin; Strandberg, Bo; Thorsson, Pontus; Pleijel, Håkan

2017-12-01

Air pollution levels (NO 2 , PAHs, O 3 ) were investigated, before (BLE) and after (ALE) leaf emergence, in the urban landscape of Gothenburg, Sweden. The aims were to study the 1) spatial and temporal variation in pollution levels between urban green areas, 2) effect of urban vegetation on air pollution levels at the same distance from a major emission source (traffic route), 3) improvement of urban air quality in urban parks compared to adjacent sites near traffic, 4) correlation between air pollution and noise in a park. O 3 varied little over the urban landscape. NO 2 varied strongly and was higher in situations strongly influenced by traffic. Four PAH variables were included: total PAH, total particle-bound PAH, the quantitatively important gaseous phenanthrene and the highly toxic particle-bound benzo(a)pyrene. The variation of PAHs was similar to NO 2 , but for certain PAHs the difference between highly and less polluted sites was larger than for NO 2 . At a vegetated site, NO 2 and particulate PAH levels were lower than at a non-vegetated site at a certain distance from a busy traffic route. This effect was significantly larger ALE compared to BLE for NO 2 , indicating green leaf area to be highly significant factor for air quality improvement. For particulate PAHs, the effect was similar BLE and ALE, indicating that tree bark and branches also could be an important factor in reducing air pollution. Parks represented considerably cleaner local environments (park effect), which is likely to be a consequence of both a dilution (distance effect) and deposition. Noise and air pollution (NO 2 and PAH) levels were strongly correlated. Comparison of noise levels BLE and ALE also showed that the presence of leaves significantly reduced noise levels. Our results are evidence that urban green spaces are beneficial for urban environmental quality, which is important to consider in urban planning. Copyright © 2017 Elsevier B.V. All rights reserved.

Luteinizing hormone (LH) levels in male workers exposed to urban stressors.

PubMed

Tomao, Enrico; Tomei, Gianfranco; Rosati, Maria Valeria; Caciari, Tiziana; Danese, Daniele; Gamberale, Daniele; Vacca, Daniele; Palermo, Paola; Anzelmo, Vincenza; Tomei, Francesco

2009-08-01

The aim of the study is to evaluate if occupational exposure to urban stressors could cause alterations in luteinizing hormone (LH) plasma levels in male traffic policemen vs. administrative staff of Municipal Police.After excluding the subjects with the main confounding factors, male traffic police and administrative staff of Municipal Police were matched by age, working life, body mass index (BMI), alcohol drinking habit, cigarette smoking habit and habitual consumption of Italian coffee.In 166 male traffic police mean LH values were significantly higher compared to 166 male administrative employees. The distribution of LH values in traffic police and in administrative employees was statistically significant.Our results suggest that recent exposure to urban stressors (chemical, physical and psycho-social) can alter the plasma concentration of LH. In agreement with our previous research, levels of plasma LH may be used as early biological markers, valuable for the group, used in occupational set before the appearance of the disease.

Road Traffic Noise Exposure and Hearing Impairment Among Traffic Policemen in Surat, Western India

NASA Astrophysics Data System (ADS)

Tandel, B. N.; Macwan, J. E. M.

2017-06-01

Among all of the sources responsible for noise pollution, traffic related sources are of great environmental concern and increasing level of discomfort in urban areas with increasing traffic concentration. It will be a larger and serious problem in the future, if effective precautions are not taken addressed and attended to. Hence, a study was undertaken to measure the levels of road traffic noise at major intersections of Surat city, located in Western India and assess the hearing impairment among the exposed group of population i.e. the traffic policemen. Manual noise measurements and vehicle counts were performed at three of the busiest traffic intersections in the city for a period of 12 h. Audiometric screening was done on 46 policemen working at these intersections to determine the occurrence of hearing impairment. At all the three intersections, Leq measured was well above the permissible levels of 65 dBA for daytime. The Lmax recorded for three intersections were 84.6 dBA (07:36 pm), 87.3 dBA (06:32 pm) and 85.6 dBA (11:41 am). Audiometric screening showed that only 10 policemen (22%) had normal hearing. Slight, moderate and severe hearing impairment was recorded among 13 (28%), 18 (39%) and 5 (11%) policemen respectively. Of the total 46 policemen, none had profound impairment (deafness, hearing loss >81 dB). Of the 36 policemen having hearing impairment, 27 had bilateral impairment.

Space evolution model and empirical analysis of an urban public transport network

NASA Astrophysics Data System (ADS)

Sui, Yi; Shao, Feng-jing; Sun, Ren-cheng; Li, Shu-jing

2012-07-01

This study explores the space evolution of an urban public transport network, using empirical evidence and a simulation model validated on that data. Public transport patterns primarily depend on traffic spatial-distribution, demands of passengers and expected utility of investors. Evolution is an iterative process of satisfying the needs of passengers and investors based on a given traffic spatial-distribution. The temporal change of urban public transport network is evaluated both using topological measures and spatial ones. The simulation model is validated using empirical data from nine big cities in China. Statistical analyses on topological and spatial attributes suggest that an evolution network with traffic demands characterized by power-law numerical values which distribute in a mode of concentric circles tallies well with these nine cities.

Impact of urban land use on the bacterial phyllosphere of ivy (Hedera sp.)

NASA Astrophysics Data System (ADS)

Smets, Wenke; Wuyts, Karen; Oerlemans, Eline; Wuyts, Sander; Denys, Siegfried; Samson, Roeland; Lebeer, Sarah

2016-12-01

The surface of the aerial parts of the plant, also termed the phyllosphere, is a selective habitat for microbes. The bacterial composition of the phyllosphere depends on host plant species, leaf characteristics, season, climate, and geographic location of the host plant. In this study, we investigated the effect of an urban environment on the bacterial composition of phyllosphere communities. We performed a passive biomonitoring experiment in which leaves were sampled from ivy (Hedera sp.), a common evergreen climber species, in urban and non-urban locations. Exposure to traffic-generated particulate matter was estimated using leaf biomagnetic analyses. The bacterial community composition was determined using 16S rRNA gene sequencing on the Illumina MiSeq. The phyllosphere microbial communities of ivy differed greatly between urban and non-urban locations, as we observed a shift in several of the dominant taxa: Beijerinckia and Methylocystaceae were most abundant in the non-urban phyllosphere, whereas Hymenobacter and Sphingomonadaceae were dominating the urban ivy phyllosphere. The richness, diversity and composition of the communities showed greater variability in the urban than in the non-urban locations, where traffic-generated PM was lower. Interestingly, the relative abundances of eight of the ten most dominant taxa correlated well with leaf magnetism, be it positive or negative. The results of this study indicate that an urban environment can greatly affect the local phyllosphere community composition. Although other urban-related factors cannot be ruled out, the relative abundance of most of the dominant taxa was significantly correlated with exposure to traffic-generated PM.

A statistical downscaling approach for roadside NO2 concentrations: Application to a WRF-Chem study for Berlin

NASA Astrophysics Data System (ADS)

Kuik, Friderike; Lauer, Axel; von Schneidemesser, Erika; Butler, Tim

2017-04-01

Many European cities continue to struggle with meeting the European air quality limits for NO2. In Berlin, Germany, most of the exceedances in NO2 recorded at monitoring sites near busy roads can be largely attributed to emissions from traffic. In order to assess the impact of changes in traffic emissions on air quality at policy relevant scales, we combine the regional atmosphere-chemistry transport model WRF-Chem at a resolution of 1kmx1km with a statistical downscaling approach. Here, we build on the recently published study evaluating the performance of a WRF-Chem setup in representing observed urban background NO2 concentrations from Kuik et al. (2016) and extend this setup by developing and testing an approach to statistically downscale simulated urban background NO2 concentrations to street level. The approach uses a multilinear regression model to relate roadside NO2 concentrations observed with the municipal monitoring network with observed NO2 concentrations at urban background sites and observed traffic counts. For this, the urban background NO2 concentrations are decomposed into a long term, a synoptic and a diurnal component using the Kolmogorov-Zurbenko filtering method. We estimate the coefficients of the regression model for five different roadside stations in Berlin representing different street types. In a next step we combine the coefficients with simulated urban background concentrations and observed traffic counts, in order to estimate roadside NO2 concentrations based on the results obtained with WRF-Chem at the five selected stations. In a third step, we extrapolate the NO2 concentrations to all major roads in Berlin. The latter is based on available data for Berlin of daily mean traffic counts, diurnal and weekly cycles of traffic as well as simulated urban background NO2 concentrations. We evaluate the NO2 concentrations estimated with this method at street level for Berlin with additional observational data from stationary measurements and mobile measurements conducted during a campaign in summer 2014. The results show that this approach allows us to estimate NO2 concentrations at roadside reasonably well. The approach can be applied when observations show a strong correlation between roadside NO2 concentrations and traffic emissions from a single type of road. The method, however, shows weaknesses for intersections where observed NO2 concentrations are influenced by traffic on several different roads. We then apply this downscaling approach to estimate the impact of different traffic emission scenarios both on urban background and street level NO2 concentrations. References Kuik, F., Lauer, A., Churkina, G., Denier van der Gon, H. A. C., Fenner, D., Mar, K. A., and Butler, T. M.: Air quality modelling in the Berlin-Brandenburg region using WRF-Chem v3.7.1: sensitivity to resolution of model grid and input data, Geosci. Model Dev., 9, 4339-4363, doi:10.5194/gmd-9-4339-2016, 2016.

An analysis on the impact of rubbernecking on urban freeway traffic.

DOT National Transportation Integrated Search

2004-08-01

An incident influences traffic not only in the incident direction but also in the : opposite direction. There has been research on the influence of incidents on the traffic in : the incident direction. However, research relating to the influence on t...

Analysis of routine traffic count stations to optimize locations and frequency : final report.

DOT National Transportation Integrated Search

1981-06-01

This report describes a grouping of statewide permanent and key traffic counters on the basis of their geographic variations in traffic flow. Several factors were considered including the distance between clusters and urban versus rural areas. : Traf...

Comparative analysis of characteristics and risk factors of traffic injury in aged people from urban and rural areas in Chongqing.

PubMed

Zhang, Liang; Zhou, Ji-Hong; Qiu, Jun; Zhang, Xiu-Zhu; Yuan, Dan-Feng; Gao, Zhi-Ming; Dai, Wei

2012-01-01

To study the epidemiologic characteristics of traffic injuries among people over 60 years old in the Nan'an district (urban) and Jiangjin district (rural) of Chongqing, and to discuss the corresponding strategies for its prevention and cure. Records of traffic injuries in people over 60 years old registered by the traffic police between 2000 and 2006 in Nan'an district and Jiangjin district were collected in the Database of Road Traffic Accidents and Traffic Injuries. Epidemiologic characteristics of traffic injuries among the aged people were analyzed and compared. Between the year 2000 and 2006, the average annual incidence of traffic injuries and mortality rate in the aged people in Nan'an district were 124.62/100 000 and 13.85/ 100 000 respectively, higher than that in Jiangjin district (27.49/ 100 000, 7.13/100 000, P less than 0.01). However, the mortality rate for the aged people who were involved in traffic injuries in Jiangjin district was 20.60%, higher than that in Nan'an district (10.00%, P less than 0.01). Head injury was the primary cause of death. Totally 76.58% of casualties were pede-strians. Over 90% of the traffic accidents occurred in the areas with no traffic signal or traffic control system. The traffic environment is unfavorable to the aged people. It is important to enhance traffic safety consciousness of drivers and the elderly and to strengthen traffic safety system and traffic law, so as to provide a safe road traffic environment for the aged people.

Control of Networked Traffic Flow Distribution - A Stochastic Distribution System Perspective

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Hong; Aziz, H M Abdul; Young, Stan

Networked traffic flow is a common scenario for urban transportation, where the distribution of vehicle queues either at controlled intersections or highway segments reflect the smoothness of the traffic flow in the network. At signalized intersections, the traffic queues are controlled by traffic signal control settings and effective traffic lights control would realize both smooth traffic flow and minimize fuel consumption. Funded by the Energy Efficient Mobility Systems (EEMS) program of the Vehicle Technologies Office of the US Department of Energy, we performed a preliminary investigation on the modelling and control framework in context of urban network of signalized intersections.more » In specific, we developed a recursive input-output traffic queueing models. The queue formation can be modeled as a stochastic process where the number of vehicles entering each intersection is a random number. Further, we proposed a preliminary B-Spline stochastic model for a one-way single-lane corridor traffic system based on theory of stochastic distribution control.. It has been shown that the developed stochastic model would provide the optimal probability density function (PDF) of the traffic queueing length as a dynamic function of the traffic signal setting parameters. Based upon such a stochastic distribution model, we have proposed a preliminary closed loop framework on stochastic distribution control for the traffic queueing system to make the traffic queueing length PDF follow a target PDF that potentially realizes the smooth traffic flow distribution in a concerned corridor.« less

Autonomous Docking Based on Infrared System for Electric Vehicle Charging in Urban Areas

PubMed Central

Pérez, Joshué; Nashashibi, Fawzi; Lefaudeux, Benjamin; Resende, Paulo; Pollard, Evangeline

2013-01-01

Electric vehicles are progressively introduced in urban areas, because of their ability to reduce air pollution, fuel consumption and noise nuisance. Nowadays, some big cities are launching the first electric car-sharing projects to clear traffic jams and enhance urban mobility, as an alternative to the classic public transportation systems. However, there are still some problems to be solved related to energy storage, electric charging and autonomy. In this paper, we present an autonomous docking system for electric vehicles recharging based on an embarked infrared camera performing infrared beacons detection installed in the infrastructure. A visual servoing system coupled with an automatic controller allows the vehicle to dock accurately to the recharging booth in a street parking area. The results show good behavior of the implemented system, which is currently deployed as a real prototype system in the city of Paris. PMID:23429581

Autonomous docking based on infrared system for electric vehicle charging in urban areas.

PubMed

Pérez, Joshué; Nashashibi, Fawzi; Lefaudeux, Benjamin; Resende, Paulo; Pollard, Evangeline

2013-02-21

Electric vehicles are progressively introduced in urban areas, because of their ability to reduce air pollution, fuel consumption and noise nuisance. Nowadays, some big cities are launching the first electric car-sharing projects to clear traffic jams and enhance urban mobility, as an alternative to the classic public transportation systems. However, there are still some problems to be solved related to energy storage, electric charging and autonomy. In this paper, we present an autonomous docking system for electric vehicles recharging based on an embarked infrared camera performing infrared beacons detection installed in the infrastructure. A visual servoing system coupled with an automatic controller allows the vehicle to dock accurately to the recharging booth in a street parking area. The results show good behavior of the implemented system, which is currently deployed as a real prototype system in the city of Paris.

Common Traffic Violations of Bus Drivers in Urban China: An Observational Study

PubMed Central

Yang, Rendong; Huang, Yuanxiu; Zhang, Lin; Ning, Peishan; Cheng, Xunjie; Schwebel, David C.

2015-01-01

Objective To report common traffic violations in bus drivers and the factors that influence those violations in urban China. Methods We conducted an observational study to record three types of traffic violations among bus drivers in Changsha City, China: illegal stopping at bus stations, violating traffic light signals, and distracted driving. The behaviors of bus drivers on 32 routes (20% of bus routes in the city) were observed. A two-level Poisson regression examined factors that predicted bus driver violations. Results The incidence of illegal stopping at bus stations was 20.2%. Illegal stopping was less frequent on weekends, sunny days, and at stations with cameras, with adjusted incidence rate ratios (IRRs) of 0.81, 0.65 and 0.89, respectively. The incidence of violating traffic light signals was 2.2%, and was lower on cloudy than sunny days (adjusted IRR: 0.60). The incidence of distracted driving was 3.3%. The incidence of distracted driving was less common on cloudy days, rainy or snowy days, and foggy/windy/dusty days compared to sunny days, with adjusted IRRs of 0.54, 0.55 and 0.07, respectively. Conclusion Traffic violations are common in bus drivers in urban China and they are associated with the date, weather, and presence of traffic cameras at bus station. Further studies are recommended to understand the behavioral mechanisms that may explain bus driver violations and to develop feasible prevention measures. PMID:26372105

Magnetic-Based NDE of Prestressed and Post-Tensioned Concrete Members: The MFL System.

DOT National Transportation Integrated Search

1997-07-01

Many metropolitan areas have begun or are planning to implement traffic monitoring programs to meet the many demands for traffic data. The purpose of this project is to document a series of examples of urban traffic monitoring data collection program...

Evaluation of the performance of the Sydney Coordinated Adaptive Traffic System (SCATS) on Powell Boulevard in Portland, OR.

DOT National Transportation Integrated Search

2013-07-01

The Sydney Coordinated Adaptive Traffic System (SCATS) is used to mitigate traffic congestion along urban arterial corridors. Although there : has been research on SCATS performance, this report combines three different areas of research about SCA...

Urban development control based on transportation carrying capacity

NASA Astrophysics Data System (ADS)

Miharja, M.; Sjafruddin, A. H.

2017-06-01

Severe transportation problems in Indonesian urban areas are stimulated by one fundamental factor, namely lack of awareness on transportation carrying capacity in these areas development control. Urban land use development towards more physical coverage is typically not related with the capability of transportation system to accommodate additional trips volume. Lack of clear connection between development permit with its implication on the transportation side has led to a phenomenon of exceeding transport demand over supply capacity. This paper discusses the concept of urban land use development control which will be related with transport carrying capacity. The discussion would cover both supply and demand sides of transportation. From supply side, the analysis regarding the capacity of transport system would take both existing as well as potential road network capacity could be developed. From demand side, the analysis would be through the control of a maximum floor area and public transport provision. Allowed maximum floor area for development would be at the level of generating traffic at reasonable volume. Ultimately, the objective of this paper is to introduce model to incorporate transport carrying capacity in Indonesian urban land use development control.

Impact of traffic volume and composition on the air quality and pedestrian exposure in urban street canyon

NASA Astrophysics Data System (ADS)

Rakowska, Agata; Wong, Ka Chun; Townsend, Thomas; Chan, Ka Lok; Westerdahl, Dane; Ng, Simon; Močnik, Griša; Drinovec, Luka; Ning, Zhi

2014-12-01

Vehicle emissions are identified as a major source of air pollution in metropolitan areas. Emission control programs in many cities have been implemented as part of larger scale transport policy interventions to control traffic pollutants and reduce public health risks. These interventions include provision of traffic-free and low emission zones and congestion charging. Various studies have investigated the impact of urban street configurations, such as street canyon in urban centers, on pollutants dispersion and roadside air quality. However, there are few investigations in the literature to study the impact of change of fleet composition and street canyon effects on the on-road pollutants concentrations and associated roadside pedestrian exposure to the pollutants. This study presents an experimental investigation on the traffic related gas and particle pollutants in and near major streets in one of the most developed business districts in Hong Kong, known as Central. Both street canyon and open roadway configurations were included in the study design. Mobile measurement techniques were deployed to monitor both on-road and roadside pollutants concentrations at different times of the day and on different days of a week. Multiple traffic counting points were also established to concurrently collect data on traffic volume and fleet composition on individual streets. Street canyon effects were evident with elevated on-road pollutants concentrations. Diesel vehicles were found to be associated with observed pollutant levels. Roadside black carbon concentrations were found to correlate with their on-road levels but with reduced concentrations. However, ultrafine particles showed very high concentrations in roadside environment with almost unity of roadside/on-road ratios possibly due to the accumulation of primary emissions and secondary PM formation. The results from the study provide useful information for the effective urban transport design and bus route reorganization to minimize the impact of traffic emissions on the urban air quality and public health. Observations on the elevated ultrafine particle concentrations in roadside pedestrian levels also demonstrate the urgent need to improve roadside air quality to reduce pedestrians' health risks especially inside street canyon.

Modelling NOX concentrations through CFD-RANS in an urban hot-spot using high resolution traffic emissions and meteorology from a mesoscale model

NASA Astrophysics Data System (ADS)

Sanchez, Beatriz; Santiago, Jose Luis; Martilli, Alberto; Martin, Fernando; Borge, Rafael; Quaassdorff, Christina; de la Paz, David

2017-08-01

Air quality management requires more detailed studies about air pollution at urban and local scale over long periods of time. This work focuses on obtaining the spatial distribution of NOx concentration averaged over several days in a heavily trafficked urban area in Madrid (Spain) using a computational fluid dynamics (CFD) model. A methodology based on weighted average of CFD simulations is applied computing the time evolution of NOx dispersion as a sequence of steady-state scenarios taking into account the actual atmospheric conditions. The inputs of emissions are estimated from the traffic emission model and the meteorological information used is derived from a mesoscale model. Finally, the computed concentration map correlates well with 72 passive samplers deployed in the research area. This work reveals the potential of using urban mesoscale simulations together with detailed traffic emissions so as to provide accurate maps of pollutant concentration at microscale using CFD simulations.

An optimal general type-2 fuzzy controller for Urban Traffic Network.

PubMed

Khooban, Mohammad Hassan; Vafamand, Navid; Liaghat, Alireza; Dragicevic, Tomislav

2017-01-01

Urban traffic network model is illustrated by state-charts and object-diagram. However, they have limitations to show the behavioral perspective of the Traffic Information flow. Consequently, a state space model is used to calculate the half-value waiting time of vehicles. In this study, a combination of the general type-2 fuzzy logic sets and the Modified Backtracking Search Algorithm (MBSA) techniques are used in order to control the traffic signal scheduling and phase succession so as to guarantee a smooth flow of traffic with the least wait times and average queue length. The parameters of input and output membership functions are optimized simultaneously by the novel heuristic algorithm MBSA. A comparison is made between the achieved results with those of optimal and conventional type-1 fuzzy logic controllers. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Enrichment and sources of trace metals in roadside soils in Shanghai, China: A case study of two urban/rural roads.

PubMed

Yan, Geng; Mao, Lingchen; Liu, Shuoxun; Mao, Yu; Ye, Hua; Huang, Tianshu; Li, Feipeng; Chen, Ling

2018-08-01

The road traffic has become one of the main sources of urban pollution and could directly affect roadside soils. To understand the level of contamination and potential sources of trace metals in roadside soils of Shanghai, 10 trace metals (Sb, Cr, Co, Ni, Cu, Cd, Pb, Hg, Mn and Zn) from two urban/rural roads (Hutai Road and Wunign-Caoan Road) were analyzed in this study. Antimony, Ni, Cu, Cd, Pb, Hg and Zn concentrations were higher than that of soil background values of Shanghai, whereas accumulation of Cr, Co and Mn were minimal. Significantly higher Sb, Cd, Pb contents were found in samples from urban areas than those from suburban area, suggesting the impact from urbanization. The concentrations of Sb and Cd in older road (Hutai) were higher than that in younger road (Wunign-Caoan). Multivariate statistical analysis revealed that Sb, Cu, Cd, Pb and Zn were mainly controlled by traffic activities (e.g. brake wear, tire wear, automobile exhaust) with high contamination levels found near traffic-intensive areas; Cr, Co, Ni and Mn derived primarily from soil parent materials; Hg was related to industrial activities. Besides, the enrichment of Sb, Cd, Cu, Pb and Zn showed a decreasing trend with distance to the road edges. According to the enrichment factors (EF s ), 78.5% of Sb, Cu, Cd, Pb and Zn were in moderate or significant pollution, indicating considerable traffic contribution. In particular, recently introduced in automotive technology, accumulation of Sb has been recognized in 42.9% samples of both roads. The accumulation of these traffic-derived metals causes potential negative impact to human health and ecological environment and should be concerned, especially the emerging trace elements like Sb. Copyright © 2018 Elsevier B.V. All rights reserved.

Mixed Traffic Information Collection System based on Pressure Sensor

NASA Astrophysics Data System (ADS)

Liao, Wenzhe; Liu, Mingsheng; Meng, Qingli

The traffic information collection is the base of Intelligent Traffic.At present, there exist mixed traffic situation in urban road in China. This paper researched and implemented a system through collecting the vehicle and bicycle mixed traffic flow parameters based on pressure sensor. According to information collection requirements, we selected pressure sensor, designed the data collection, storage and other hardware circuitries and information processing software. The experiment shows that the system can meet the demand of traffic information collection in the actual.

Trust-Based Cooperative Social System Applied to a Carpooling Platform for Smartphones

PubMed Central

Caballero-Gil, Cándido; Caballero-Gil, Pino; Molina-Gil, Jezabel; Martín-Fernández, Francisco; Loia, Vincenzo

2017-01-01

One of the worst traffic problems today is the existence of huge traffic jams in almost any big city, produced by the large number of commuters using private cars. This problem has led to an increase in research on the optimization of vehicle occupancy in urban areas as this would help to solve the problem that most cars are occupied by single passengers. The solution of sharing the available seats in cars, known as carpooling, is already available in major cities around the world. However, carpooling is still not considered a safe and reliable solution for many users. With the widespread use of mobile technology and social networks, it is possible to create a trust-based platform to promote carpooling through a convenient, fast and secure system. The main objective of this work is the design and implementation of a carpool system that improves some important aspects of previous systems, focusing on trust between users, and on the security of the system. The proposed system guarantees user privacy and measures trust levels through a new reputation algorithm. In addition to this, the proposal has been developed as a mobile application for devices using the Android Open Source Project. PMID:28134803

Collective Human Mobility Pattern from Taxi Trips in Urban Area

PubMed Central

Peng, Chengbin; Jin, Xiaogang; Wong, Ka-Chun; Shi, Meixia; Liò, Pietro

2012-01-01

We analyze the passengers' traffic pattern for 1.58 million taxi trips of Shanghai, China. By employing the non-negative matrix factorization and optimization methods, we find that, people travel on workdays mainly for three purposes: commuting between home and workplace, traveling from workplace to workplace, and others such as leisure activities. Therefore, traffic flow in one area or between any pair of locations can be approximated by a linear combination of three basis flows, corresponding to the three purposes respectively. We name the coefficients in the linear combination as traffic powers, each of which indicates the strength of each basis flow. The traffic powers on different days are typically different even for the same location, due to the uncertainty of the human motion. Therefore, we provide a probability distribution function for the relative deviation of the traffic power. This distribution function is in terms of a series of functions for normalized binomial distributions. It can be well explained by statistical theories and is verified by empirical data. These findings are applicable in predicting the road traffic, tracing the traffic pattern and diagnosing the traffic related abnormal events. These results can also be used to infer land uses of urban area quite parsimoniously. PMID:22529917

Investigation of powered 2-wheeler accident involvement in urban arterials by considering real-time traffic and weather data.

PubMed

Theofilatos, Athanasios; Yannis, George

2017-04-03

Understanding the various factors that affect accident risk is of particular concern to decision makers and researchers. The incorporation of real-time traffic and weather data constitutes a fruitful approach when analyzing accident risk. However, the vast majority of relevant research has no specific focus on vulnerable road users such as powered 2-wheelers (PTWs). Moreover, studies using data from urban roads and arterials are scarce. This study aims to add to the current knowledge by considering real-time traffic and weather data from 2 major urban arterials in the city of Athens, Greece, in order to estimate the effect of traffic, weather, and other characteristics on PTW accident involvement. Because of the high number of candidate variables, a random forest model was applied to reveal the most important variables. Then, the potentially significant variables were used as input to a Bayesian logistic regression model in order to reveal the magnitude of their effect on PTW accident involvement. The results of the analysis suggest that PTWs are more likely to be involved in multivehicle accidents than in single-vehicle accidents. It was also indicated that increased traffic flow and variations in speed have a significant influence on PTW accident involvement. On the other hand, weather characteristics were found to have no effect. The findings of this study can contribute to the understanding of accident mechanisms of PTWs and reduce PTW accident risk in urban arterials.

Assessment of long-term and large-scale even-odd license plate controlled plan effects on urban air quality and its implication

NASA Astrophysics Data System (ADS)

Zhao, Suping; Yu, Ye; Qin, Dahe; Yin, Daiying; He, Jianjun

2017-12-01

To solve traffic congestion and to improve urban air quality, long-lasting and large-scale even-odd license plate controlled plan was implemented by local government during 20 November to 26 December 2016 in urban Lanzhou, a semi-arid valley city of northwest China. The traffic control measures provided an invaluable opportunity to evaluate its effects on urban air quality in less developed cities of northwest China. Based on measured simultaneously air pollutants and meteorological parameters, the abatement of traffic-related pollutants induced by the implemented control measures such as CO, PM2.5 and PM10 (the particulate matter with diameter less than 2.5 μm and 10 μm) concentrations were firstly quantified by comparing the air quality data in urban areas with those in rural areas (uncontrolled zones). The concentrations of CO, NO2 from motor vehicles and fine particulate matter (PM2.5) were shown to have significant decreases of 15%-23% during traffic control period from those measured before control period with hourly maximum CO, PM2.5, and NO2/SO2 reduction of 43%, 35% and 141.4%, respectively. The influence of the control measures on AQI (air quality index) and ozone was less as compared to its effect on other air pollutants. Therefore, to alleviate serious winter haze pollution in China and to protect human health, the stringent long-term and large-scale even-odd license plate controlled plan should be implemented aperiodically in urban areas, especially for the periods with poor diffusion conditions.

An Optimal Schedule for Urban Road Network Repair Based on the Greedy Algorithm

PubMed Central

Lu, Guangquan; Xiong, Ying; Wang, Yunpeng

2016-01-01

The schedule of urban road network recovery caused by rainstorms, snow, and other bad weather conditions, traffic incidents, and other daily events is essential. However, limited studies have been conducted to investigate this problem. We fill this research gap by proposing an optimal schedule for urban road network repair with limited repair resources based on the greedy algorithm. Critical links will be given priority in repair according to the basic concept of the greedy algorithm. In this study, the link whose restoration produces the ratio of the system-wide travel time of the current network to the worst network is the minimum. We define such a link as the critical link for the current network. We will re-evaluate the importance of damaged links after each repair process is completed. That is, the critical link ranking will be changed along with the repair process because of the interaction among links. We repair the most critical link for the specific network state based on the greedy algorithm to obtain the optimal schedule. The algorithm can still quickly obtain an optimal schedule even if the scale of the road network is large because the greedy algorithm can reduce computational complexity. We prove that the problem can obtain the optimal solution using the greedy algorithm in theory. The algorithm is also demonstrated in the Sioux Falls network. The problem discussed in this paper is highly significant in dealing with urban road network restoration. PMID:27768732

Evaluation of an urban traffic Noise-Exposed population based on points of interest and noise maps: The case of Guangzhou.

PubMed

Wang, Haibo; Chen, Hanjie; Cai, Ming

2018-08-01

The primary objective of this study was to develop an evaluation method for assessing an urban traffic noise-exposed population and apply it in the main urban area of Guangzhou. The method based on points of interest (POIs) and noise map is realized in several steps. First, after regionalizing based on road networks and executing a cluster analysis for regions according to the properties of POIs, the environmental noise functional regions (NFRs) of the urban area are presented. Then, surrounding POIs are used to infer the type of buildings, and according to the attraction of different building types and the whole population of the region, the population distribution at the building level is calculated. Finally, with the help of a noise map, an evaluation method for assessing an urban traffic noise-exposed population is proposed. The method is applied in the main urban area of Guangzhou, and the results reveal the followings. 1) At daytime and nighttime, 23.63% and 30.53% of the population, respectively, experience noise levels that exceed the noise standards. The per capita noise exposure value at daytime and nighttime is 0.9 dB and 2.0 dB, respectively. 2) The percentages of the exposed population of Yuexiu District were 28.89% at daytime and 35.65% at nighttime, which are the largest, followed by the exposed population percentages of Liwan, Haizhu, and Tianhe Districts. 3) From the view of different classes of NFRs, the percentages of the exposed population of Class 1 and Class 4 are larger than the percentages of the exposed population from the other classes, especially at nighttime (48.24% of Class 1 and 40.79% of Class 4). 4) Although there are masses of people affected by traffic noise, a large percentage of them (85%) experience not more than 5 dB of traffic noise superscale. Copyright © 2018 Elsevier Ltd. All rights reserved.

The burden of road traffic injuries in Nigeria: results of a population-based survey.

PubMed

Labinjo, M; Juillard, C; Kobusingye, O C; Hyder, A A

2009-06-01

Mortality from road traffic injuries in sub-Saharan Africa is among the highest in the world, yet data from the region are sparse. To date, no multi-site population-based survey on road traffic injuries has been reported from Nigeria, the most populated country in Africa. To explore the epidemiology of road traffic injury in Nigeria and provide data on the populations affected and risk factors for road traffic injury. Data from a population-based survey using two-stage stratified cluster sampling. SUBJECTS/ SETTING: Road traffic injury status and demographic information were collected on 3082 respondents living in 553 households in seven of Nigeria's 37 states. Incidence rates were estimated with confidence intervals based on a Poisson distribution; Poisson regression analysis was used to calculate relative risks for associated factors. The overall road traffic injury rate was 41 per 1000 population (95% CI 34 to 49), and mortality from road traffic injuries was 1.6 per 1000 population (95% CI 0.5 to 3.8). Motorcycle crashes accounted for 54% of all road traffic injuries. The road traffic injury rates found for rural and urban respondents were not significantly different. Increased risk of injury was associated with male gender among those aged 18-44 years, with a relative risk of 2.96 when compared with women in the same age range (95% CI 1.72 to 5.09, p<0.001). The road traffic injury rates found in this survey highlight a neglected public health problem in Nigeria. Simple extrapolations from this survey suggest that over 4 million people may be injured and as many as 200 000 potentially killed as the result of road traffic crashes annually in Nigeria. Appropriate interventions in both the health and transport sectors are needed to address this significant cause of morbidity and mortality in Nigeria.

Urban traffic noise and self-reported health.

PubMed

Gómez-Jacinto, L; Moral-Toranzo, F

1999-06-01

This paper analyzed urban traffic noise effects on health at two different levels: intense noise and moderate noise. 42 residents of the area responded to questions on perceived noise and psychological and behavior disturbance before and after acoustic insulation was constructed. Analysis of self-reports indicated that perceived noise was associated with lower health. Also these perceived effects on health did not decrease after the acoustic isolation work was finished.

Quality of traffic flow on urban arterial streets and its relationship with safety.

PubMed

Dixit, Vinayak V; Pande, Anurag; Abdel-Aty, Mohamed; Das, Abhishek; Radwan, Essam

2011-09-01

The two-fluid model for vehicular traffic flow explains the traffic on arterials as a mix of stopped and running vehicles. It describes the relationship between the vehicles' running speed and the fraction of running vehicles. The two parameters of the model essentially represent 'free flow' travel time and level of interaction among vehicles, and may be used to evaluate urban roadway networks and urban corridors with partially limited access. These parameters are influenced by not only the roadway characteristics but also by behavioral aspects of driver population, e.g., aggressiveness. Two-fluid models are estimated for eight arterial corridors in Orlando, FL for this study. The parameters of the two-fluid model were used to evaluate corridor level operations and the correlations of these parameters' with rates of crashes having different types/severity. Significant correlations were found between two-fluid parameters and rear-end and angle crash rates. Rate of severe crashes was also found to be significantly correlated with the model parameter signifying inter-vehicle interactions. While there is need for further analysis, the findings suggest that the two-fluid model parameters may have potential as surrogate measures for traffic safety on urban arterial streets. Copyright © 2011 Elsevier Ltd. All rights reserved.

Analyzing lead concentration in the sycamore tree species in high- and low-traffic areas of Rasht, Iran.

PubMed

Hashemi, Seyed Armin; Alinejad, Farzaneh; FallahChay, Mozaffar

2015-06-01

Important heavy metals such as lead and cadmium are part of the pollutants produced by cars and are spread in the urban environment by traffic flow. In order to study the amount of contamination in the trees along the streets and to determine the traffic parameters that affect the lead content in sycamore leaves in Rasht, four stations on the margins of the city streets were selected for this case study in terms of traffic volume (low or high). Traffic parameters including three high-traffic stations considering daily and monthly traffic volumes and one low-traffic station were selected. First, 32 sycamore bases were randomly chosen at the intervals of 10-15 m from the whole range of tree canopy in order to determine the absorption of lead; and then, 20 g of each sample were tested to determine the amount of lead absorption. The results of this study, on the amount of lead absorption by the sycamore tree species at three high-traffic and one control station, showed that Takhti station had the highest amount of lead absorption (37.19 ppm) compared with other three stations. Therefore, the sycamore tree species can be an appropriate one for the margins of urban streets. © The Author(s) 2013.

Reasons underlying behaviour of motorcyclists disregarding traffic regulations in urban areas of Indonesia.

PubMed

Susilo, Yusak O; Joewono, Tri Basuki; Vandebona, Upali

2015-02-01

Over the last decade, motorcycle use has been rapidly increasing in Indonesia as have violations of traffic rules committed by motorcyclists. This study aims to explore the impacts of motorcyclists' attitudes, habits, preferences, and travel patterns on their behaviour in disregarding traffic regulations in three cities in Indonesia. The theory of planned behaviour and structural equation modelling are employed to explore these relationships. Consistent with results from previous studies in developed countries, an individual's beliefs and attitudes, social norms and perceived behaviour control significantly influence behaviour in disregarding traffic rules. Young adults and students are found to be more likely to frequently violate traffic regulations. However, unlike previous findings from developed countries, in Indonesia, males are less likely to disregard traffic rules than females. Overall, pushing the motorcycle through a (very) narrow gap, speeding, driving recklessly, and overtaking on the wrong side are the most frequent traffic violations that make up repetitive violation behaviour among urban motorcyclists in Indonesia. The results highlight the need to revisit Indonesian National Traffic Law traffic violation classification and penalties and separate violations that are likely to cause fatal results, thus requiring tougher law enforcement, from violations that are unlikely to have fatal consequences. Copyright © 2014 Elsevier Ltd. All rights reserved.

Tiering strategic environmental assessment and project environmental impact assessment in highway planning in Sao Paulo, Brazil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sanchez, Luis E.; Silva-Sanchez, Solange S.

2008-10-15

Constructing highways in dense urban areas is always a challenge. In Sao Paulo Metropolitan Region, heavy truck traffic contributes to clog streets and expressways alike. As part of the traffic neither originates nor head to the region, a peripheral highway has been proposed to reduce traffic problems. This project, called Rodoanel, is an expressway approximately 175 km long. The fact that the projected south and north sections would cross catchments that supply most of the metropolis water demand was strongly disputed and made the environmental permitting process particularly difficult. The agency in charge commissioned a strategic environmental assessment (SEA) ofmore » a revamped project, and called it the Rodoanel Programme. However, the SEA report failed to satisfactorily take account of significant strategic issues. Among these, the highway potential effect of inducing urban sprawl over water protection zones is the most critical issue, as it emerged later as a hurdle to project licensing. Conclusion is that, particularly where no agreed-upon framework for SEA exists, when vertical tiering with downstream project EIA is sought, then a careful scoping of strategic issues is more than necessary. If an agreement on 'what is strategic' is not reached and not recognized by influential stakeholders, then the unsettled conflicts will be transferred to project EIA. In such a context, SEA will have added another loop to the usually long road to project approval.« less

10 CFR 420.15 - Minimum criteria for required program activities for plans.

Code of Federal Regulations, 2014 CFR

2014-01-01

.../vanpool matching and promotion campaign; (ii) Park-and-ride lots; (iii) Preferential traffic control for... employees; (x) Urban area traffic restrictions; (xi) Geographical or time restrictions on automobile use; or... efficiency standards for renovated buildings. (e) A traffic law or regulation which permits the operator of a...

10 CFR 420.15 - Minimum criteria for required program activities for plans.

Code of Federal Regulations, 2013 CFR

2013-01-01

.../vanpool matching and promotion campaign; (ii) Park-and-ride lots; (iii) Preferential traffic control for... employees; (x) Urban area traffic restrictions; (xi) Geographical or time restrictions on automobile use; or... efficiency standards for renovated buildings. (e) A traffic law or regulation which permits the operator of a...

10 CFR 420.15 - Minimum criteria for required program activities for plans.

Code of Federal Regulations, 2012 CFR

2012-01-01

.../vanpool matching and promotion campaign; (ii) Park-and-ride lots; (iii) Preferential traffic control for... employees; (x) Urban area traffic restrictions; (xi) Geographical or time restrictions on automobile use; or... efficiency standards for renovated buildings. (e) A traffic law or regulation which permits the operator of a...

Potential of dynamic spectrum allocation in LTE macro networks

NASA Astrophysics Data System (ADS)

Hoffmann, H.; Ramachandra, P.; Kovács, I. Z.; Jorguseski, L.; Gunnarsson, F.; Kürner, T.

2015-11-01

In recent years Mobile Network Operators (MNOs) worldwide are extensively deploying LTE networks in different spectrum bands and utilising different bandwidth configurations. Initially, the deployment is coverage oriented with macro cells using the lower LTE spectrum bands. As the offered traffic (i.e. the requested traffic from the users) increases the LTE deployment evolves with macro cells expanded with additional capacity boosting LTE carriers in higher frequency bands complemented with micro or small cells in traffic hotspot areas. For MNOs it is crucial to use the LTE spectrum assets, as well as the installed network infrastructure, in the most cost efficient way. The dynamic spectrum allocation (DSA) aims at (de)activating the available LTE frequency carriers according to the temporal and spatial traffic variations in order to increase the overall LTE system performance in terms of total network capacity by reducing the interference. This paper evaluates the DSA potential of achieving the envisaged performance improvement and identifying in which system and traffic conditions the DSA should be deployed. A self-optimised network (SON) DSA algorithm is also proposed and evaluated. The evaluations have been carried out in a hexagonal and a realistic site-specific urban macro layout assuming a central traffic hotspot area surrounded with an area of lower traffic with a total size of approximately 8 × 8 km2. The results show that up to 47 % and up to 40 % possible DSA gains are achievable with regards to the carried system load (i.e. used resources) for homogenous traffic distribution with hexagonal layout and for realistic site-specific urban macro layout, respectively. The SON DSA algorithm evaluation in a realistic site-specific urban macro cell deployment scenario including realistic non-uniform spatial traffic distribution shows insignificant cell throughput (i.e. served traffic) performance gains. Nevertheless, in the SON DSA investigations, a gain of up to 25 % has been observed when analysing the resource utilisation in the non-hotspot cells.

Quantitative assessment of human health risk posed by polycyclic aromatic hydrocarbons in urban road dust.

PubMed

Ma, Yukun; Liu, An; Egodawatta, Prasanna; McGree, James; Goonetilleke, Ashantha

2017-01-01

Among the numerous pollutants present in urban road dust, polycyclic aromatic hydrocarbons (PAHs) are among the most toxic chemical pollutants and can pose cancer risk to humans. The primary aim of the study was to develop a quantitative model to assess the cancer risk from PAHs in urban road dust based on traffic and land use factors and thereby to characterise the risk posed by PAHs in fine (<150μm) and coarse (>150μm) particles. The risk posed by PAHs was quantified as incremental lifetime cancer risk (ILCR), which was modelled as a function of traffic volume and percentages of different urban land uses. The study outcomes highlighted the fact that cancer risk from PAHs in urban road dust is primarily influenced by PAHs associated with fine solids. Heavy PAHs with 5 to 6 benzene rings, especially dibenzo[a,h]anthracene (D[a]A) and benzo[a]pyrene (B[a]P) in the mixture contribute most to the risk. The quantitative model developed based on traffic and land use factors will contribute to informed decision making in relation to the management of risk posed by PAHs in urban road dust. Copyright © 2016 Elsevier B.V. All rights reserved.

Perceptual assessment of quality of urban soundscapes with combined noise sources and water sounds.

PubMed

Jeon, Jin Yong; Lee, Pyoung Jik; You, Jin; Kang, Jian

2010-03-01

In this study, urban soundscapes containing combined noise sources were evaluated through field surveys and laboratory experiments. The effect of water sounds on masking urban noises was then examined in order to enhance the soundscape perception. Field surveys in 16 urban spaces were conducted through soundwalking to evaluate the annoyance of combined noise sources. Synthesis curves were derived for the relationships between noise levels and the percentage of highly annoyed (%HA) and the percentage of annoyed (%A) for the combined noise sources. Qualitative analysis was also made using semantic scales for evaluating the quality of the soundscape, and it was shown that the perception of acoustic comfort and loudness was strongly related to the annoyance. A laboratory auditory experiment was then conducted in order to quantify the total annoyance caused by road traffic noise and four types of construction noise. It was shown that the annoyance ratings were related to the types of construction noise in combination with road traffic noise and the level of the road traffic noise. Finally, water sounds were determined to be the best sounds to use for enhancing the urban soundscape. The level of the water sounds should be similar to or not less than 3 dB below the level of the urban noises.

Evaluation of the social and economic burden of road traffic noise-attributed myocardial infarction in Bulgarian urban population.

PubMed

Dzhambov, Angel M; Dimitrova, Donka D

2015-03-01

Road traffic noise is a widely studied environmental risk factor for ischaemic heart disease and myocardial infarction in particular. Given that myocardial infarction is a leading disability and mortality cause in Bulgaria and that a significant proportion of the urban population is exposed to high noise levels, quantification of the burden of disease attributable to traffic noise is essential for environmental health policy making and noise control engineering. This study aimed at estimating the burden of the myocardial infarction cases attributable to road traffic noise in the Bulgarian urban population. We used the methodology for estimating the burden of disease attributable to environmental noise outlined by the World Health Organization. Risk data were extracted from a recently published meta-analysis providing updated exposure-response relationship between traffic noise and the risk for myocardial infarction. Based on these data we calculated the fraction of myocardial infarction cases attributable to traffic noise, loss of quality-adjusted life-years (QALYs), and the economic burden, assuming € 12,000 per QALY. About 2.9 % or 101 of all myocardial infarction cases could be attributed to road traffic noise. Fifty-five of these were fatal. Nine hundred and sixty-eight QALYs were lost to these cases. The monetary value of these QALYs was about € 11.6 million. Although the measures used in this study are crude and give only an approximation of the real burden of disease from road traffic noise, they are indicative of the important social and economic aspect of noise pollution in Bulgaria. Hopefully, these results will direct the attention of epidemiologists, environmental hygienists, and health economists to this pivotal environmental issue.

Polycyclic aromatic hydrocarbons (PAHs) concentration levels, pattern, source identification and soil toxicity assessment in urban traffic soil of Dhanbad, India.

PubMed

Suman, Swapnil; Sinha, Alok; Tarafdar, Abhrajyoti

2016-03-01

Present study was carried out to assess and understand potential health risk and to examine the impact of vehicular traffic on the contamination status of urban traffic soils in Dhanbad City with respect to polycyclic aromatic hydrocarbons (PAHs). Eight urban traffic sites and two control/rural site surface soils were analyzed and the contents of 13 priority PAHs was determined. Total PAH concentration at traffic sites ranged from 1.019 μg g(-1) to 10.856 μg g(-1) with an average value of 3.488 μg g(-1). At control/rural site, average concentration of total PAHs was found to be 0.640 μg g(-1). PAH pattern was dominated by four- and five-ring PAHs (contributing >50% to the total PAHs) at all the eight traffic sites. On the other hand, rural soil showed a predominance of low molecular weight three-ring PAHs (contributing >30% to the total PAHs). Indeno[123-cd]pyrene/benz[ghi]perylene (IP/BgP) ratio indicated that PAH load at the traffic sites is predominated by the gasoline-driven vehicles. The ratio of Ant/(Ant+Phe) varied from 0.03 to 0.44, averaging 0.10; Fla/(Fla+Pyr) from 0.39 to 0.954, averaging 0.52; BaA/(BaA+Chry) from 0.156 to 0.60, averaging 0.44; and IP/(IP+BgP) from 0.176 to 0.811, averaging 0.286. The results indicated that vehicular emission was the major source for PAHs contamination with moderate effect of coal combustion and biomass combustion. Carcinogenic potency of PAH load in traffic soil was nearly 6.15 times higher as compared to the control/rural soil. Copyright © 2015 Elsevier B.V. All rights reserved.

Stereo-based Collision Avoidance System for Urban Traffic

NASA Astrophysics Data System (ADS)

Moriya, Takashi; Ishikawa, Naoto; Sasaki, Kazuyuki; Nakajima, Masato

2002-11-01

Numerous car accidents occur on urban road. However, researches done so far on driving assistance are subjecting highways whose environment is relatively simple and easy to handle, and new approach for urban settings is required. Our purpose is to extend its support to the following conditions in city traffic: the presence of obstacles such as pedestrians and telephone poles; the lane mark is not always drawn on a road; drivers may lack the sense of awareness of the lane mark. We propose a collision avoidance system, which can be applied to both highways and urban traffic environment. In our system, stereo cameras are set in front of a vehicle and the captured images are processed through a computer. We create a Projected Disparity Map (PDM) from stereo image pair, which is a disparity histogram taken along ordinate direction of obtained disparity image. When there is an obstacle in front, we can detect it by finding a peak appeared in the PDM. With a speed meter and a steering sensor, the stop distance and the radius of curvature of the self-vehicle are calculated, in order to set the observation-required area, which does not depend on lane marks, within a PDM. A danger level will be computed from the distance and the relative speed to the closest approaching object detected within the observation-required area. The method has been tested in urban traffic scenes and has shown to be effective for judging dangerous situation, and gives proper alarm to a driver.

Gis-Based Route Finding Using ANT Colony Optimization and Urban Traffic Data from Different Sources

NASA Astrophysics Data System (ADS)

Davoodi, M.; Mesgari, M. S.

2015-12-01

Nowadays traffic data is obtained from multiple sources including GPS, Video Vehicle Detectors (VVD), Automatic Number Plate Recognition (ANPR), Floating Car Data (FCD), VANETs, etc. All such data can be used for route finding. This paper proposes a model for finding the optimum route based on the integration of traffic data from different sources. Ant Colony Optimization is applied in this paper because the concept of this method (movement of ants in a network) is similar to urban road network and movements of cars. The results indicate that this model is capable of incorporating data from different sources, which may even be inconsistent.

The urban environment and health in a world of increasing globalization: issues for developing countries.

PubMed Central

McMichael, A. J.

2000-01-01

Urban living is the keystone of modern human ecology. Cities have multiplied and expanded rapidly worldwide over the past two centuries. Cities are sources of creativity and technology, and they are the engines for economic growth. However, they are also sources of poverty, inequality, and health hazards from the environment. Urban populations have long been incubators and gateways for infectious diseases. The early industrializing period of unplanned growth and laissez-faire economic activity in cities in industrialized countries has been superseded by the rise of collective management of the urban environment. This occurred in response to environmental blight, increasing literacy, the development of democratic government, and the collective accrual of wealth. In many low-income countries, this process is being slowed by the pressures and priorities of economic globalization. Beyond the traditional risks of diarrhoeal disease and respiratory infections in the urban poor and the adaptation of various vector-borne infections to urbanization, the urban environment poses various physicochemical hazards. These include exposure to lead, air pollution, traffic hazards, and the "urban heat island" amplification of heatwaves. As the number of urban consumers and their material expectations rise and as the use of fossil fuels increases, cities contribute to the large-scale pressures on the biosphere including climate change. We must develop policies that ameliorate the existing, and usually unequally distributed, urban environmental health hazards and larger-scale environmental problems. PMID:11019460

The urban environment and health in a world of increasing globalization: issues for developing countries.

PubMed

McMichael, A J

2000-01-01

Urban living is the keystone of modern human ecology. Cities have multiplied and expanded rapidly worldwide over the past two centuries. Cities are sources of creativity and technology, and they are the engines for economic growth. However, they are also sources of poverty, inequality, and health hazards from the environment. Urban populations have long been incubators and gateways for infectious diseases. The early industrializing period of unplanned growth and laissez-faire economic activity in cities in industrialized countries has been superseded by the rise of collective management of the urban environment. This occurred in response to environmental blight, increasing literacy, the development of democratic government, and the collective accrual of wealth. In many low-income countries, this process is being slowed by the pressures and priorities of economic globalization. Beyond the traditional risks of diarrhoeal disease and respiratory infections in the urban poor and the adaptation of various vector-borne infections to urbanization, the urban environment poses various physicochemical hazards. These include exposure to lead, air pollution, traffic hazards, and the "urban heat island" amplification of heatwaves. As the number of urban consumers and their material expectations rise and as the use of fossil fuels increases, cities contribute to the large-scale pressures on the biosphere including climate change. We must develop policies that ameliorate the existing, and usually unequally distributed, urban environmental health hazards and larger-scale environmental problems.

Development of a Quantitative Methodology to Assess the Impacts of Urban Transport Interventions and Related Noise on Well-Being

PubMed Central

Braubach, Matthias; Tobollik, Myriam; Mudu, Pierpaolo; Hiscock, Rosemary; Chapizanis, Dimitris; Sarigiannis, Denis A.; Keuken, Menno; Perez, Laura; Martuzzi, Marco

2015-01-01

Well-being impact assessments of urban interventions are a difficult challenge, as there is no agreed methodology and scarce evidence on the relationship between environmental conditions and well-being. The European Union (EU) project “Urban Reduction of Greenhouse Gas Emissions in China and Europe” (URGENCHE) explored a methodological approach to assess traffic noise-related well-being impacts of transport interventions in three European cities (Basel, Rotterdam and Thessaloniki) linking modeled traffic noise reduction effects with survey data indicating noise-well-being associations. Local noise models showed a reduction of high traffic noise levels in all cities as a result of different urban interventions. Survey data indicated that perception of high noise levels was associated with lower probability of well-being. Connecting the local noise exposure profiles with the noise-well-being associations suggests that the urban transport interventions may have a marginal but positive effect on population well-being. This paper also provides insight into the methodological challenges of well-being assessments and highlights the range of limitations arising from the current lack of reliable evidence on environmental conditions and well-being. Due to these limitations, the results should be interpreted with caution. PMID:26016437

Development of a quantitative methodology to assess the impacts of urban transport interventions and related noise on well-being.

PubMed

Braubach, Matthias; Tobollik, Myriam; Mudu, Pierpaolo; Hiscock, Rosemary; Chapizanis, Dimitris; Sarigiannis, Denis A; Keuken, Menno; Perez, Laura; Martuzzi, Marco

2015-05-26

Well-being impact assessments of urban interventions are a difficult challenge, as there is no agreed methodology and scarce evidence on the relationship between environmental conditions and well-being. The European Union (EU) project "Urban Reduction of Greenhouse Gas Emissions in China and Europe" (URGENCHE) explored a methodological approach to assess traffic noise-related well-being impacts of transport interventions in three European cities (Basel, Rotterdam and Thessaloniki) linking modeled traffic noise reduction effects with survey data indicating noise-well-being associations. Local noise models showed a reduction of high traffic noise levels in all cities as a result of different urban interventions. Survey data indicated that perception of high noise levels was associated with lower probability of well-being. Connecting the local noise exposure profiles with the noise-well-being associations suggests that the urban transport interventions may have a marginal but positive effect on population well-being. This paper also provides insight into the methodological challenges of well-being assessments and highlights the range of limitations arising from the current lack of reliable evidence on environmental conditions and well-being. Due to these limitations, the results should be interpreted with caution.

Characterizing heavy metal build-up on urban road surfaces: implication for stormwater reuse.

PubMed

Liu, An; Liu, Liang; Li, Dunzhu; Guan, Yuntao

2015-05-15

Stormwater reuse is increasingly popular in the worldwide. In terms of urban road stormwater, it commonly contains toxic pollutants such as heavy metals, which could undermine the reuse safety. The research study investigated heavy metal build-up characteristics on urban roads in a typical megacity of South China. The research outcomes show the high variability in heavy metal build-up loads among different urban road sites. The degree of traffic congestion and road surface roughness was found to exert a more significant influence on heavy metal build-up rather than traffic volume. Due to relatively higher heavy metal loads, stormwater from roads with more congested traffic conditions or rougher surfaces might be suitable for low-water-quality required activities while the stormwater from by-pass road sections could be appropriate for relatively high-water-quality required purposes since the stormwater could be relatively less polluted. Based on the research outcomes, a decision-making process for heavy metals based urban road stormwater reuse was proposed. The new finding highlights the importance to undertaking a "fit-for-purpose" road stormwater reuse strategy. Additionally, the research results can also contribute to enhancing stormwater reuse safety. Copyright © 2015 Elsevier B.V. All rights reserved.

Enhanced Framework for Modeling Urban Truck Trips

DOT National Transportation Integrated Search

1998-09-16

Recently there has been renewed interest in modeling urban truck movements. : This is potentially important for improving traffic forecasts as well as for a : host of other applications including ITS. There are unique aspects of urban : freight movem...

[HYGIENIC ASSESSMENT OF NOISE FACTOR OF THE LARGE CITY].

PubMed

Chubirko, M L; Stepkin, Yu I; Seredenko, O V

2015-01-01

The article is devoted to the problem of the negative impact of traffic noise on the health and living conditions of the population in conditions of the large city. Every day on the streets there are appeared more and more different modes of transport, and to date almost all transportation network has reached his traffic performance. The increase in traffic noise certainly has an impact on the human body. The most common and intense noise is caused by the traffic of urban automobile and electric transport. This is explained by the existence of the heavy traffic (2-3 thousand crews/h) on almost all main roads in historically emerged parts of the city. In addition, sources of external noise in the city can be a railway running in residential zone, access roads, industrial enterprises, located in close proximity to residential areas and on the borders of residential zones, planes of military and civil aviation. For the evaluation of the different noises sound levels were measured with the use of sound level meters. The most common parameter for the assessment ofthe noise generatedfrom motor vehicles on residential areas and usedfor the noise characteristics of the traffic flows, is the equivalent sound level/A EQ dB. This parameter is used in the majority of normative-technical documentation as hygienic noise standard. With the aim of the assessment of noise exposure there were selected 122 control points at intersections of roads of different traffic performance where there were made instrumental measurements the equivalent sound level, followed by its comparison with permissible levels.

[Reduction of automobile traffic: urgent health promotion policy].

PubMed

Tapia Granados, J A

1998-03-01

During the last few decades, traffic injuries have become one of the leading causes of death and disability in the world. In urban areas, traffic congestion, noise, and emissions from motor vehicles produce subjective disturbances and detectable pathological effects. More than one billion people are exposed to harmful levels of environmental pollution. Because its combustion engine generates carbon dioxide (CO2), the automobile is one of the chief sources of the gases that are causing the greenhouse effect. The latter has already caused a rise in the average ambient temperature, and over the next decades it will predictable cause significant climatic changes whose consequences, though uncertain, are likely to be harmful and possibly catastrophic. Aside from the greenhouse effect, the relentless growth of parking zones, traffic, and the roadway infrastructure in urban and rural areas is currently one of the leading causes of environmental degradation. Urban development, which is nearly always "planned" around traffic instead of people, leads to a significant deterioration in the quality of life, while it also destroys the social fabric. Unlike the private automobile, public transportation, bicycles, and walking help reduce pollution, congestion, and traffic volume, as well as the morbidity and mortality resulting from injuries and ailments related to pollution. Non-automobile transportation also encourages physical activity--with its positive effect on general health--and helps reduce the greenhouse effect. The drop in traffic volume and the increased use of alternate means of transportation are thus an integrated health promotion policy which should become an inherent part of the movement for the promotion of healthy cities and of transportation policies and economic policy in general.

Active transportation safety features around schools in Canada.

PubMed

Pinkerton, Bryn; Rosu, Andrei; Janssen, Ian; Pickett, William

2013-10-31

The purpose of this study was to describe the presence and quality of active transportation safety features in Canadian school environments that relate to pedestrian and bicycle safety. Variations in these features and associated traffic concerns as perceived by school administrators were examined by geographic status and school type. The study was based on schools that participated in 2009/2010 Health Behaviour in School-aged Children (HBSC) survey. ArcGIS software version 10 and Google Earth were used to assess the presence and quality of ten different active transportation safety features. Findings suggest that there are crosswalks and good sidewalk coverage in the environments surrounding most Canadian schools, but a dearth of bicycle lanes and other traffic calming measures (e.g., speed bumps, traffic chokers). Significant urban/rural inequities exist with a greater prevalence of sidewalk coverage, crosswalks, traffic medians, and speed bumps in urban areas. With the exception of bicycle lanes, the active transportation safety features that were present were generally rated as high quality. Traffic was more of a concern to administrators in urban areas. This study provides novel information about active transportation safety features in Canadian school environments. This information could help guide public health efforts aimed at increasing active transportation levels while simultaneously decreasing active transportation injuries.

Active Transportation Safety Features around Schools in Canada

PubMed Central

Pinkerton, Bryn; Rosu, Andrei; Janssen, Ian; Pickett, William

2013-01-01

The purpose of this study was to describe the presence and quality of active transportation safety features in Canadian school environments that relate to pedestrian and bicycle safety. Variations in these features and associated traffic concerns as perceived by school administrators were examined by geographic status and school type. The study was based on schools that participated in 2009/2010 Health Behaviour in School-aged Children (HBSC) survey. ArcGIS software version 10 and Google Earth were used to assess the presence and quality of ten different active transportation safety features. Findings suggest that there are crosswalks and good sidewalk coverage in the environments surrounding most Canadian schools, but a dearth of bicycle lanes and other traffic calming measures (e.g., speed bumps, traffic chokers). Significant urban/rural inequities exist with a greater prevalence of sidewalk coverage, crosswalks, traffic medians, and speed bumps in urban areas. With the exception of bicycle lanes, the active transportation safety features that were present were generally rated as high quality. Traffic was more of a concern to administrators in urban areas. This study provides novel information about active transportation safety features in Canadian school environments. This information could help guide public health efforts aimed at increasing active transportation levels while simultaneously decreasing active transportation injuries. PMID:24185844

Spatial and temporal trends from an air quality sensor network near a heavily trafficked intersection

NASA Astrophysics Data System (ADS)

Orlando, P.; Vo, D.; Giossi, C.; George, L.

2017-12-01

With the world-wide increase in urbanization and the increasing usage of combustion vehicles in urban areas, traffic-related air pollution is a growing health hazard. However, there are limited studies that examine the spatial and temporal impacts of traffic-related pollutants within cities. In particular, there are few studies that look at traffic management and its potential for pollution mitigation. In a previous study we examined roadway pollution and traffic parameters with one roadway station instrumented with standard measurement instruments. With the advent of low-cost air pollution sensors, we have expanded our work by observing multiple sites within a neighborhood to understand spatial and temporal exposures. We have deployed a high-density sensor network around urban arterial corridors in SE Portland, Oregon. This network consisted of ten nodes measuring CO, NO, NO2 and O3, and ten nodes measuring CO, CO2, VOC and PM2.5. The co-location of standard measurement instruments provided insight towards the utility of our low-cost sensor network, as the different nodes varied in cost, and potentially in quality. We have identified near-real-time temporal trends and local-scale spatial patterns during the summer of 2017. Meteorological and traffic data were included to further characterize these patterns, exploring the potential for pollution mitigation.

Follicle-stimulating hormone levels in female workers exposed to urban pollutants.

PubMed

Ciarrocca, Manuela; Caciari, Tiziana; Ponticiello, Barnaba Giuseppina; Gioffrè, Pier Agostino; Tomei, Gianfranco; Sancini, Angela; Schifano, Maria Pia; Palermo, Paola; Nardone, Nadia; Scimitto, Lara; Fiaschetti, Maria; Tomei, Francesco

2011-12-01

The aim of this study was to evaluate if there were alterations in FSH plasma levels in female outdoor workers (traffic policewomen and drivers) exposed to chemical urban stressors vs. control group. After excluding subjects with main confounding factors, traffic policewomen, drivers and indoor workers were matched by age, working life, socioeconomic status, marital status, menstrual cycle day, age of menarche, habitual consumption of Italian coffee and soy. A total of 129 female subjects were included in the study: some 63 workers studied during proliferative phase and 66 during secretory phase of menstrual cycle. Proliferative phase of menstrual cycle: FSH mean values were significantly higher in traffic policewomen compared to controls (p < 0.05). Results suggest that in outdoor workers exposed to urban chemical stressors there are alterations in FSH levels; therefore FSH may be used as an early biological marker, valuable for the group, used in occupational set.

Predictors of road traffic accident, road traffic injury and death among commercial motorcyclists in an urban area of Nigeria.

PubMed

Adogu, P O U; Ilika, A L; Asuzu, A L

2009-01-01

Road traffic accidents, injuries and deaths remain important public health problems in both developed and developing countries. These problems have since escalated with the introduction of the new phenomenon of commercial motorcycle transportation such as is found in the urbanizing slum of Nnewi, Anambra state of Nigeria. Using a semi-structured, interviewer-administered questionnaire, relevant data on socio-demographic and motorcycle characteristics were collected from a sample of 291 commercial motorcyclists selected by systematic sampling technique. Data on RTA, RTI and death were also collected from them overa period of three months. The result showed that young commercial motorcyclists {<30 years of age}, experienced higher fatal injury rate than older ones {> or =30 years of age}, {p < 0.01}. Motorcyclists with some formal education experienced RTA and RTI incidence rates that were significantly lower than those of motorcyclists with no formal education, {p < 0.01}. In the same vein, medical condition and social vices such as alcohol intake among the motorcyclists were found to be obvious predictors of RTA, RTI and death. Furthermore, motorcyclists who used >100 cc engine capacity motorcycles had significantly higher RTA incidence rate {478.8/100 MCY}, RTI rate {223.2/100 MCY} and FIR {410/100 MCY} than users of <100 cc engine motorcycles who recorded RTA incidence of 258.9/100 MCY, RTI rate of 49/100 MCY and zero fatal injury respectively {p < 0.01, p < 0.001, p < 0.001 respectively}. A careful consideration of all these predictors individually and collectively, will enable stakeholders in transport industry plan effective RTA, RTI and death control measures. Rather than an outright ban of motorcycle transportation, evening classes can be organized for the motorcyclists at subsidized rates to improve their literacy levels to run side by side with road safety informational lessons delivered at their places of work.

[Health risk assessment of traffic-related air pollution near busy roads].

PubMed

Host, S; Chatignoux, E; Leal, C; Grémy, I

2012-08-01

Although ambient urban air pollution has well-established health effects, epidemiology faces many difficulties in estimating the risks due to exposure to traffic pollutants near busy roads. This review aims to summarize how exposure to traffic-related air pollution near busy roads is assessed in epidemiological studies and main findings regarding health effects. After presenting the specificity of emissions due to traffic road, this review identifies the key methods and main results found in epidemiologic studies seeking to measure the influence of exposure to nearby traffic on health published over the past decade. The characterization and measurement of population exposure to traffic pollution faces many difficulties. Thus, epidemiological studies have used two broad categories of surrogates to assess exposure: direct measures of traffic itself such as distance of the residence to the nearest road and traffic volume and modeled concentrations of pollutant surrogates. Studies that implemented these methods showed that people living near heavy traffic road or exposed to near-road air pollution tend to report more health outcomes. Traffic-related air pollution near busy roads is the subject of increasing attention, and tends to be better characterized. However, its health impacts remain difficult to grasp, especially because of the vast diversity of approaches used in epidemiological studies. Greater consistency in the protocols would be desirable to provide better understanding of the health issue of traffic in urban areas and thus to better implement policies to protect those most at risk. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Temporal variation of traffic on highways and the development of accurate temporal allocation factors for air pollution analyses

NASA Astrophysics Data System (ADS)

Batterman, Stuart; Cook, Richard; Justin, Thomas

2015-04-01

Traffic activity encompasses the number, mix, speed and acceleration of vehicles on roadways. The temporal pattern and variation of traffic activity reflects vehicle use, congestion and safety issues, and it represents a major influence on emissions and concentrations of traffic-related air pollutants. Accurate characterization of vehicle flows is critical in analyzing and modeling urban and local-scale pollutants, especially in near-road environments and traffic corridors. This study describes methods to improve the characterization of temporal variation of traffic activity. Annual, monthly, daily and hourly temporal allocation factors (TAFs), which describe the expected temporal variation in traffic activity, were developed using four years of hourly traffic activity data recorded at 14 continuous counting stations across the Detroit, Michigan, U.S. region. Five sites also provided vehicle classification. TAF-based models provide a simple means to apportion annual average estimates of traffic volume to hourly estimates. The analysis shows the need to separate TAFs for total and commercial vehicles, and weekdays, Saturdays, Sundays and observed holidays. Using either site-specific or urban-wide TAFs, nearly all of the variation in historical traffic activity at the street scale could be explained; unexplained variation was attributed to adverse weather, traffic accidents and construction. The methods and results presented in this paper can improve air quality dispersion modeling of mobile sources, and can be used to evaluate and model temporal variation in ambient air quality monitoring data and exposure estimates.

Temporal variation of traffic on highways and the development of accurate temporal allocation factors for air pollution analyses

PubMed Central

Batterman, Stuart; Cook, Richard; Justin, Thomas

2015-01-01

Traffic activity encompasses the number, mix, speed and acceleration of vehicles on roadways. The temporal pattern and variation of traffic activity reflects vehicle use, congestion and safety issues, and it represents a major influence on emissions and concentrations of traffic-related air pollutants. Accurate characterization of vehicle flows is critical in analyzing and modeling urban and local-scale pollutants, especially in near-road environments and traffic corridors. This study describes methods to improve the characterization of temporal variation of traffic activity. Annual, monthly, daily and hourly temporal allocation factors (TAFs), which describe the expected temporal variation in traffic activity, were developed using four years of hourly traffic activity data recorded at 14 continuous counting stations across the Detroit, Michigan, U.S. region. Five sites also provided vehicle classification. TAF-based models provide a simple means to apportion annual average estimates of traffic volume to hourly estimates. The analysis shows the need to separate TAFs for total and commercial vehicles, and weekdays, Saturdays, Sundays and observed holidays. Using either site-specific or urban-wide TAFs, nearly all of the variation in historical traffic activity at the street scale could be explained; unexplained variation was attributed to adverse weather, traffic accidents and construction. The methods and results presented in this paper can improve air quality dispersion modeling of mobile sources, and can be used to evaluate and model temporal variation in ambient air quality monitoring data and exposure estimates. PMID:25844042

Traffic sign detection in MLS acquired point clouds for geometric and image-based semantic inventory

NASA Astrophysics Data System (ADS)

Soilán, Mario; Riveiro, Belén; Martínez-Sánchez, Joaquín; Arias, Pedro

2016-04-01

Nowadays, mobile laser scanning has become a valid technology for infrastructure inspection. This technology permits collecting accurate 3D point clouds of urban and road environments and the geometric and semantic analysis of data became an active research topic in the last years. This paper focuses on the detection of vertical traffic signs in 3D point clouds acquired by a LYNX Mobile Mapper system, comprised of laser scanning and RGB cameras. Each traffic sign is automatically detected in the LiDAR point cloud, and its main geometric parameters can be automatically extracted, therefore aiding the inventory process. Furthermore, the 3D position of traffic signs are reprojected on the 2D images, which are spatially and temporally synced with the point cloud. Image analysis allows for recognizing the traffic sign semantics using machine learning approaches. The presented method was tested in road and urban scenarios in Galicia (Spain). The recall results for traffic sign detection are close to 98%, and existing false positives can be easily filtered after point cloud projection. Finally, the lack of a large, publicly available Spanish traffic sign database is pointed out.

Dispersion Modeling of Traffic-Related Air Pollutant Exposures and Health Effects among Children with Asthma in Detroit, Michigan

EPA Science Inventory

Vehicular traffic is a major source of ambient air pollution in urban areas, and traffic-related air pollutants, including carbon monoxide, nitrogen oxides, particulate matter under 2.5 microns in diameter (PM_2.5) and diesel exhaust emissions, have been associated with...

Follicle-stimulating hormone levels in male workers exposed to urban chemical, physical, and psychosocial stressors.

PubMed

Tomei, G; Tomao, E; Ciarrocca, M; Rosati, M V; Caciari, T; Gamberale, D; Palermo, P; De Sio, S; Tria, M; Panfili, A; Tomei, F

2009-07-01

The aim of this study is to evaluate whether occupational exposure to urban stressors could cause alterations in the follicle-stimulating hormone (FSH) levels in traffic policemen compared to a control group. After excluding the subjects with main confounding factors, traffic policemen and male controls were matched by age, working life, body mass index (BMI), drinking habit, cigarette smoking history, and daily consumption of Italian coffee, 166 traffic policemen and 166 controls were included into the study. FSH levels were significantly higher in traffic policemen compared to male controls (P < 0.05). The distribution of FSH values in traffic policemen and controls was significant (P < 0.05). Our results suggest that occupational exposure to low doses of chemical and psychosocial stressors may alter plasma levels of FSH in traffic policemen more than in the control group. If the results obtained are confirmed by further research, the plasma levels of FSH may be used as early biological markers, valuable for the group, used in occupational set even before the appearance of disorders of male fertility.

Modelling Urban Noise in Citygml Ade: Case of the Netherlands

NASA Astrophysics Data System (ADS)

Kumar, K.; Ledoux, H.; Commandeur, T. J. F.; Stoter, J. E.

2017-10-01

Road traffic and industrial noise has become a major source of discomfort and annoyance among the residents in urban areas. More than 44 % of the EU population is regularly exposed to road traffic noise levels over 55 dB, which is currently the maximum accepted value prescribed by the Environmental Noise Directive for road traffic noise. With continuously increasing population and number of motor vehicles and industries, it is very unlikely to hope for noise levels to diminish in the near future. Therefore, it is necessary to monitor urban noise, so as to make mitigation plans and to deal with its adverse effects. The 2002/49/EC Environmental Noise Directive aims to determine the exposure of an individual to environmental noise through noise mapping. One of the most important steps in noise mapping is the creation of input data for simulation. At present, it is done semi-automatically (and sometimes even manually) by different companies in different ways and is very time consuming and can lead to errors in the data. In this paper, we present our approach for automatically creating input data for noise simulations. Secondly, we focus on using 3D city models for presenting the results of simulation for the noise arising from road traffic and industrial activities in urban areas. We implemented a few noise modelling standards for industrial and road traffic noise in CityGML by extending the existing Noise ADE with new objects and attributes. This research is a steping stone in the direction of standardising the input and output data for noise studies and for reconstructing the 3D data accordingly.

Managing incidents on urban arterial roadways

DOT National Transportation Integrated Search

1997-01-01

Limiting the impact on traffic of nonrecurring events such as crashes, traffic stops, or disabled vehicles through effective incident management should be one objective for emergency response professionals. Moreover, such management is an integral pa...

Trip-oriented travel time prediction (TOTTP) with historical vehicle trajectories

NASA Astrophysics Data System (ADS)

Xu, Tao; Li, Xiang; Claramunt, Christophe

2018-06-01

Accurate travel time prediction is undoubtedly of importance to both traffic managers and travelers. In highly-urbanized areas, trip-oriented travel time prediction (TOTTP) is valuable to travelers rather than traffic managers as the former usually expect to know the travel time of a trip which may cross over multiple road sections. There are two obstacles to the development of TOTTP, including traffic complexity and traffic data coverage.With large scale historical vehicle trajectory data and meteorology data, this research develops a BPNN-based approach through integrating multiple factors affecting trip travel time into a BPNN model to predict trip-oriented travel time for OD pairs in urban network. Results of experiments demonstrate that it helps discover the dominate trends of travel time changes daily and weekly, and the impact of weather conditions is non-trivial.

A cellular automation model accounting for bicycle's group behavior

NASA Astrophysics Data System (ADS)

Tang, Tie-Qiao; Rui, Ying-Xu; Zhang, Jian; Shang, Hua-Yan

2018-02-01

Recently, bicycle has become an important traffic tool in China, again. Due to the merits of bicycle, the group behavior widely exists in urban traffic system. However, little effort has been made to explore the impacts of the group behavior on bicycle flow. In this paper, we propose a CA (cellular automaton) model with group behavior to explore the complex traffic phenomena caused by shoulder group behavior and following group behavior on an open road. The numerical results illustrate that the proposed model can qualitatively describe the impacts of the two kinds of group behaviors on bicycle flow and that the effects are related to the mode and size of group behaviors. The results can help us to better understand the impacts of the bicycle's group behaviors on urban traffic system and effectively control the bicycle's group behavior.

Feasibility study on intersection in North Sumatera

NASA Astrophysics Data System (ADS)

Hastuty, I. P.; Sembiring, I. S.; Anas, R.; Lubis, A. S.

2018-02-01

Traffic congestion is one of the problems faced by big cities, One of them is Binjai city and Medan city in North Sumatera. One of the causes of congestion is intersection of roads with highway and roads with railroads. To ensure the smooth movement of vehicles, technical handling at the intersection is needed. Therefore, it is necessary to pre-study the feasibility of level crossing in Binjai and Medan to be able to assess the investment needs and the level of importance of road development in the region. The development of transportation infrastructure and facilities is based on the thought of improving the transportation network system. The necessity of systemical integrated transportation system handling is needed in creating a transportation efficiency. The purpose of this study is to identify and prioritize the needs of the railway crossings. The objective which we want to be achieved is to obtain a document that contains technical, economic and environmental ability indicators as a reference in the feasibility and planning studies. The methodology used is collecting the primary data, secondary data, introduction of study area as the initial analysis of the problem. From the study it can be concluded that the existence of railway interchange will move the movement through traffic so it will not interfere the movement of traffic within urban areas and it keeps the national road network performance is still good.

[Epidemiological profile of traffic-related disability in Peru, 2012].

PubMed

Gutiérrez, César; Romaní, Franco; Wong-Chero, Paolo; Montenegro-Idrogo, Juan José

2014-04-01

To describe the epidemiological profile of people living with disabilities due to traffic accidents (TA) in Peru. Secondary analysis of the National Survey Specialized on Disability (ENEDIS) of 2012 and an ecological analysis of TA records of the Ministry of Transportation and Communications was done. Disability by traffic accidents (DAT) was reported by 49,036 persons; 81.3% of whom live in urban areas. The most frequent disability was limited locomotion and skill (77.4%), followed by visual impairment (22.9%). Dependence for activities was reported in 44.7% of persons with disabilities. The regions with the highest prevalence of TA have a higher prevalence of disability by traffic accidents (Spearman coefficient: 0.426, p=0.034). Most of disability due to TA is found in urban areas, correspond to males and consist of persons in economically productive age. The most common form of disability is in locomotion. Most of individuals do not receive any form of rehabilitation, which accentuates health inequity related to traffic accidents.

Characterisation of an urban bus network for environmental purposes.

PubMed

André, Michel; Villanova, André

2004-12-01

Since pollutant emissions are closely related to the operating conditions of vehicles, their evaluation usually involves studying these operating conditions (through bus instrumentation and monitoring under actual operation), the design of representative driving or engine test cycles and the measurement of pollutant emissions. A preliminary characterisation of the routes on a bus network should make it possible to identify typical routes, the driving conditions and pollutant emissions of which are then studied. Two approaches are envisaged and applied to the Paris area, for which a wealth of information is available, which should be transferable to other bus networks. Both approaches are based on factorial analysis and automatic clustering, to allow optimum description and the identification of a pertinent typology of the bus routes in several classes. The first attempt at characterisation is based on statistics relating to bus operations: route characteristics (length, dedicated bus lanes, number of stops, location of stops: schools, tourist sites, hospitals, railways or underground stations), travel time, commercial speed, annual statistics (number of passengers, number of vehicles per hour, total kilometres), the irregularity of travel (variation of travel times, injuries, congestion.), as well as information on the problems encountered (congestion, distribution of the passenger load, junctions, bends). A second approach is based on the analysis of the "urban context" in which buses are driven. Population, employment, housing, road network, traffic and places that generate or disturb traffic (schools, railway stations, shopping areas, etc.) are calculated for the Ile de France region, by cells of 100 x 100 m, and collected in a geographical information system (GIS). Statistical analyses enable a typology of these urban cells to be established, the main parameters being density, type of housing, road types and traffic levels. The bus routes are then analysed according to their itineraries across these typical areas (distances travelled in each type of area) using a similar approach. A comparison of the typologies obtained from operational data and from urban data highlights the advantages and disadvantages of the two approaches. The first result from these typologies is the selection of routes which are representative of the different classes, in order to instrument buses and record driving patterns. This method should also make it possible to link driving conditions and urban characteristics, and then to allocate pollutant emission factors to given geographical situations, in particular, in the context of emission inventories or impact studies.

Conduct urban agglomeration with the baton of transportation.

DOT National Transportation Integrated Search

2013-12-01

A key indicator of traffic activity patterns is commuting distance. Shorter commuting distances yield less traffic, fewer emissions, : and lower energy consumption. This study develops a spatial error seemingly unrelated regression model to investiga...

Performance measures for arterial traffic signal systems.

DOT National Transportation Integrated Search

2009-05-01

This project was conducted to investigate new concepts, new tools and emerging technologies directed at enhancing traffic operations and safety on signalized urban arterials that operate under saturated conditions. McFarland Boulevard, a six-lane urb...

Effects of heavy vehicles on dynamic traffic features.

DOT National Transportation Integrated Search

2016-02-01

Traffic congestion on highways has been growing in urban areas where freight transportation hubs reside, affecting the efficiency and reliability of freight transportation. This research will investigate the effects of heavy vehicles on dynamic traff...

Passive Sensor Integration for Vehicle Self-Localization in Urban Traffic Environment †

PubMed Central

Gu, Yanlei; Hsu, Li-Ta; Kamijo, Shunsuke

2015-01-01

This research proposes an accurate vehicular positioning system which can achieve lane-level performance in urban canyons. Multiple passive sensors, which include Global Navigation Satellite System (GNSS) receivers, onboard cameras and inertial sensors, are integrated in the proposed system. As the main source for the localization, the GNSS technique suffers from Non-Line-Of-Sight (NLOS) propagation and multipath effects in urban canyons. This paper proposes to employ a novel GNSS positioning technique in the integration. The employed GNSS technique reduces the multipath and NLOS effects by using the 3D building map. In addition, the inertial sensor can describe the vehicle motion, but has a drift problem as time increases. This paper develops vision-based lane detection, which is firstly used for controlling the drift of the inertial sensor. Moreover, the lane keeping and changing behaviors are extracted from the lane detection function, and further reduce the lateral positioning error in the proposed localization system. We evaluate the integrated localization system in the challenging city urban scenario. The experiments demonstrate the proposed method has sub-meter accuracy with respect to mean positioning error. PMID:26633420

Realities of weather extremes on daily life in urban India - How quantified impacts infer sensible adaptation options

NASA Astrophysics Data System (ADS)

Reckien, D.

2012-12-01

Emerging and developing economies are currently undergoing one of the profoundest socio-spatial transitions in their history, with strong urbanization and weather extremes bringing about changes in the economy, forms of living and living conditions, but also increasing risks and altered social divides. The impacts of heat waves and strong rain events are therefore differently perceived among urban residents. Addressing the social differences of climate change impacts1 and expanding targeted adaptation options have emerged as urgent policy priorities, particularly for developing and emerging economies2. This paper discusses the perceived impacts of weather-related extreme events on different social groups in New Delhi and Hyderabad, India. Using network statistics and scenario analysis on Fuzzy Cognitive Maps (FCMs) as part of a vulnerability analysis, the investigation provides quantitative and qualitative measures to compare impacts and adaptation strategies for different social groups. Impacts of rain events are stronger than those of heat in both cities and affect the lower income classes particularly. Interestingly, the scenario analysis (comparing altered networks in which the alteration represents a possible adaptation measure) shows that investments in the water infrastructure would be most meaningful and more effective than investments in, e.g., the traffic infrastructure, despite the stronger burden from traffic disruptions and the resulting concentration of planning and policy on traffic ease and investments. The method of Fuzzy Cognitive Mapping offers a link between perception and modeling, and the possibility to aggregate and analyze the views of a large number of stakeholders. Our research has shown that planners and politicians often know about many of the problems, but are often overwhelmed by the problems in their respective cities and look for a prioritization of adaptation options. FCM provides this need and identifies priority adaptation options when resources are scarce. 1 Parry ML, Canziani OF, Palutikof JP, van der Linden PJ, Hanson CE (eds) (2007) Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge New York. 2 TERI (2007) Adaptation to Climate Change in the context of Sustainable Development. Background Paper to the conference ''Climate Change and Sustainable Development: An international workshop to strengthen research and understanding'', 7-8 April 2006, The Energy and Resources Institute, New Delhi.

Endocrine disrupting compounds in the atmosphere of the urban area of Thessaloniki, Greece

NASA Astrophysics Data System (ADS)

Salapasidou, M.; Samara, C.; Voutsa, D.

2011-07-01

The aim of this study was to investigate the occurrence of endocrine disrupting compounds (EDCs) in a complex urban atmosphere. Target compounds were alkylphenols (NP, tOP, nOP), nonylphenol monoethoxylate (NP1EO), bisphenol A (BPA), tetrabromobisphenol A (TBBPA), and phthalates (DMP, DEP, DBP, BBP, DEHP, DNOP). EDCs were determined in ambient PM10 from two sampling sites, one urban-traffic and one urban-industrial, located in the city of Thessaloniki, northern Greece. At both sites, DEHP and NP were found to be the predominant EDCs in airborne PM10. Concentrations of NP did not exhibit any spatial difference, whereas concentrations of DEHP were significantly higher at the urban-traffic site. Wind direction was not found to have any significant effect on ambient EDCs concentrations suggesting impact from local sources rather than transport; however some peak concentrations might be attributed to short-distance sources. The gas/particle partition coefficient, Kp, and the gaseous phase of EDCs were calculated by employing two approaches based on literature data (a) for the subcooled liquid vapor pressure ( PL0) and (b) the octanol-air partition coefficient ( KOA). It appeared that the g/ p partition of phthalates estimated by the KOA approach is in better agreement with experimental partition data reported by other investigators. Absorption in organic matter was found to be significant partition mechanism at the urban-traffic site.

Effects of air pollution on lung function and symptoms of asthma, rhinitis and eczema in primary school children.

PubMed

Altuğ, Hicran; Gaga, Eftade O; Döğeroğlu, Tuncay; Ozden, Ozlem; Ornektekin, Sermin; Brunekreef, Bert; Meliefste, Kees; Hoek, Gerard; Van Doorn, Wim

2013-09-01

Health effects of ambient air pollution were studied in three groups of schoolchildren living in areas (suburban, urban and urban-traffic) with different air pollution levels in Eskişehir, Turkey. This study involved 1,880 students aged between 9 and 13 years from 16 public primary schools. This two-season study was conducted from January 2008 through March 2009. Symptoms of asthma, rhinitis and eczema were determined by the International Study of Asthma and Allergies in Childhood questionnaire in 2008. Two lung function tests were performed by each child for summer and winter seasons with simultaneous ambient air measurements of ozone (O3), nitrogen dioxide (NO2) and sulfur dioxide (SO2) by passive sampling. Effects of air pollution on impaired lung function and symptoms in schoolchildren were estimated by multivariate logistic regression analyses. Girls with impaired lung function (only for the summer season evaluation) were more observed in suburban and urban areas when compared to urban-traffic area ([odds ratio (OR) = 1.49; 95 % confidence interval (CI) 1.04-2.14] and [OR = 1.69 (95 % CI 1.06-2.71)] for suburban vs. urban-traffic and urban vs. urban-traffic, respectively). Significant association between ambient ozone concentrations and impaired lung function (for an increase of 10 μg m(-3)) was found only for girls for the summer season evaluation [OR = 1.11 (95 % CI 1.03-1.19)]. No association was found for boys and for the winter season evaluation. No association was found between any of the measured air pollutants and symptoms of current wheeze, current rhinoconjunctivitis and current itchy rash. The results of this study showed that increasing ozone concentrations may cause a sub-acute impairment in lung function of school aged children.

The Traffic Noise Index: A Method of Controlling Noise Nuisance.

ERIC Educational Resources Information Center

Langdon, F. J.; Scholes, W. E.

This building research survey is an analysis of the social nuisance caused by urban motor ways and their noise. The Traffic Noise Index is used to indicate traffic noises and their effects on architectural designs and planning, while suggesting the need for more and better window insulation and acoustical barriers. Overall concern is for--(1)…

The Traffic Adaptive Data Dissemination (TrAD) Protocol for both Urban and Highway Scenarios.

PubMed

Tian, Bin; Hou, Kun Mean; Zhou, Haiying

2016-06-21

The worldwide economic cost of road crashes and injuries is estimated to be US$518 billion per year and the annual congestion cost in France is estimated to be €5.9 billion. Vehicular Ad hoc Networks (VANETs) are one solution to improve transport features such as traffic safety, traffic jam and infotainment on wheels, where a great number of event-driven messages need to be disseminated in a timely way in a region of interest. In comparison with traditional wireless networks, VANETs have to consider the highly dynamic network topology and lossy links due to node mobility. Inter-Vehicle Communication (IVC) protocols are the keystone of VANETs. According to our survey, most of the proposed IVC protocols focus on either highway or urban scenarios, but not on both. Furthermore, too few protocols, considering both scenarios, can achieve high performance. In this paper, an infrastructure-less Traffic Adaptive data Dissemination (TrAD) protocol which takes into account road traffic and network traffic status for both highway and urban scenarios will be presented. TrAD has double broadcast suppression techniques and is designed to adapt efficiently to the irregular road topology. The performance of the TrAD protocol was evaluated quantitatively by means of realistic simulations taking into account different real road maps, traffic routes and vehicular densities. The obtained simulation results show that TrAD is more efficient in terms of packet delivery ratio, number of transmissions and delay in comparison with the performance of three well-known reference protocols. Moreover, TrAD can also tolerate a reasonable degree of GPS drift and still achieve efficient data dissemination.

Characterization of traffic-related ambient fine particulate matter (PM2.5) in an Asian city: Environmental and health implications

NASA Astrophysics Data System (ADS)

Zhang, Zhi-Hui; Khlystov, Andrey; Norford, Leslie K.; Tan, Zhen-Kang; Balasubramanian, Rajasekhar

2017-07-01

Vehicular traffic emission is an important source of particulate pollution in most urban areas. The detailed chemical speciation of traffic-related PM2.5 (fine particles) is relatively sparse in the literature, especially in Asian cities. To fill this knowledge gap, we carried out an intensive field study in Singapore from November 2015 to February 2016. PM2.5 samples were collected concurrently at a typical roadside microenvironment and at an urban background site. A detailed chemical speciation of PM2.5 samples was conducted to gain insights into the emission characteristics of traffic-related fine aerosols. Analyses of diagnostic ratios and molecular markers of selected chemical species were explored for source attribution of different classes of chemical constituents in traffic-related PM2.5. The human health risk due to inhalation of the particulate-bound PAHs (polycyclic aromatic hydrocarbons) and toxic trace elements was estimated for both adults and children. The overall results of the study indicate that gasoline-powered vehicles make a higher contribution to traffic-related fine aerosol components such as organic carbon (OC), particle-bound PAHs and particulate ammonium than that of diesel-powered vehicles. However, both types of vehicles contribute to traffic-related EC emissions significantly. The combustion of petroleum fuels and lubricating oil make significant contributions to the emission of n-alkanes and hopanes into the urban atmosphere, respectively. The study further reveals that some toxic trace elements are emitted from non-exhaust sources and that aromatic acids represent an important component of secondary organic aerosols. The emission of toxic trace elements from non-exhaust sources is of particular concern as they could pose a higher carcinogenic risk to both adults and children than other chemical species.

The Traffic Adaptive Data Dissemination (TrAD) Protocol for both Urban and Highway Scenarios

PubMed Central

Tian, Bin; Hou, Kun Mean; Zhou, Haiying

2016-01-01

The worldwide economic cost of road crashes and injuries is estimated to be US$518 billion per year and the annual congestion cost in France is estimated to be €5.9 billion. Vehicular Ad hoc Networks (VANETs) are one solution to improve transport features such as traffic safety, traffic jam and infotainment on wheels, where a great number of event-driven messages need to be disseminated in a timely way in a region of interest. In comparison with traditional wireless networks, VANETs have to consider the highly dynamic network topology and lossy links due to node mobility. Inter-Vehicle Communication (IVC) protocols are the keystone of VANETs. According to our survey, most of the proposed IVC protocols focus on either highway or urban scenarios, but not on both. Furthermore, too few protocols, considering both scenarios, can achieve high performance. In this paper, an infrastructure-less Traffic Adaptive data Dissemination (TrAD) protocol which takes into account road traffic and network traffic status for both highway and urban scenarios will be presented. TrAD has double broadcast suppression techniques and is designed to adapt efficiently to the irregular road topology. The performance of the TrAD protocol was evaluated quantitatively by means of realistic simulations taking into account different real road maps, traffic routes and vehicular densities. The obtained simulation results show that TrAD is more efficient in terms of packet delivery ratio, number of transmissions and delay in comparison with the performance of three well-known reference protocols. Moreover, TrAD can also tolerate a reasonable degree of GPS drift and still achieve efficient data dissemination. PMID:27338393

Study of aircraft in intraurban transportation systems, San Francisco Bay area

NASA Technical Reports Server (NTRS)

1972-01-01

The nine-county San Francisco Bay area is examined in two time periods (1975-1980 and 1985-1990) as a scenario for analyzing the characteristics of an intraurban, commuter-oriented aircraft transportation system. Aircraft have dominated the long-haul passenger market for some time, but efforts to penetrate the very-short-haul intraurban market have met with only token success. Yet, the characteristics of an aircraft transportation system, speed and flexibility, are very much needed to solve the transportation ills of our major urban areas. The aircraft intraurban system is a technically feasible alternative to ground transportation systems. Although requiring some subsidy, it becomes socially viable where substantial commuter traffic exists at ranges of 10 to 15 mi or more and where topographic features constrain ground travel. The general problem areas of community noise, air traffic congestion, ground transportation interface, pollution, and safety appear to have workable solutions.

An evaluation of the effects of neighborhood mobilization on community problems.

PubMed

Donnelly, Patrick G

2006-01-01

This research examines the outcomes of actions taken by members of a residential neighborhood association to revitalize a neighborhood and to make it a safer and more secure place to live. This urban neighborhood association initiated a major planning process in cooperation with city officials. Residents overwhelmingly adopted the plan that included the creation of mini-neighborhoods with a series of gates to moderate traffic flow, increase neighborliness, and reduce crime. An analysis of official data from police crime reports shows that crime was significantly reduced in the neighborhood after the street changes. This reduction in crime was maintained even five years later. Telephone interviews with neighborhood residents indicated that they perceived reductions in traffic, crime, noise and drug offenses for at least five years after the changes. Even though neighborhood cohesion did not increase, it appears that the actions instigated and promoted by neighborhood association members enhanced the quality of life for neighborhood residents.

TH-36 full closure construction evaluation of traffic operations alternatives.

DOT National Transportation Integrated Search

2010-01-01

According to the 2007 Urban Mobility Report, $78 billion was lost due to congestion on urban roadways. Many : urban corridors around the country experience demand that is close to or greater than the available capacity. : Although most agree that the...

Determinants of aerosol lung-deposited surface area variation in an urban environment.

PubMed

Reche, Cristina; Viana, Mar; Brines, Mariola; Pérez, Noemí; Beddows, David; Alastuey, Andrés; Querol, Xavier

2015-06-01

Ultrafine particles are characterized by a high surface area per mass. Particle surface has been reported to play a significant role in determining the toxicological activity of ultrafine particles. In light of this potential role, the time variation of lung deposited surface area (LDSA) concentrations in the alveolar region was studied at the urban background environment of Barcelona (Spain), aiming to asses which processes and sources govern this parameter. Simultaneous data on Black Carbon (BC), total particle number (N) and particle number size distribution were correlated with LDSA. Average LDSA concentrations in Barcelona were 37 ± 26 μm(2)cm(-3), levels which seem to be characteristic for urban environments under traffic influence across Europe. Results confirm the comparability between LDSA data provided by the online monitor and those calculated based on particle size distributions (by SMPS), and reveal that LDSA concentrations are mainly influenced by particles in the size range 50-200 nm. A set of representative daily cycles for LDSA concentrations was obtained by means of a k-means cluster technique. The contribution of traffic emissions to daily patterns was evidenced in all the clusters, but was quantitatively different. Traffic events under stable atmospheric conditions increased mean hourly background LDSA concentrations up to 6 times, attaining levels higher than 200 μm(2)cm(-3). However, under warm and relatively clean atmospheric conditions, the traffic rush hour contribution to the daily LDSA mean appeared to be lower and the contribution of new urban particle formation events (by photochemically induced nucleation) was detected. These nucleation events were calculated to increase average background LDSA concentrations by 15-35% (maximum LDSA levels=45-50 μm(2)cm(-3)). Thereby, it may be concluded that in the urban background of Barcelona road traffic is the main source increasing the aerosol surface area which can deposit on critical regions of the human lung, followed by nucleation episodes. Copyright © 2015 Elsevier B.V. All rights reserved.

Estimated long-term outdoor air pollution concentrations in a cohort study

NASA Astrophysics Data System (ADS)

Beelen, Rob; Hoek, Gerard; Fischer, Paul; Brandt, Piet A. van den; Brunekreef, Bert

Several recent studies associated long-term exposure to air pollution with increased mortality. An ongoing cohort study, the Netherlands Cohort Study on Diet and Cancer (NLCS), was used to study the association between long-term exposure to traffic-related air pollution and mortality. Following on a previous exposure assessment study in the NLCS, we improved the exposure assessment methods. Long-term exposure to nitrogen dioxide (NO 2), nitrogen oxide (NO), black smoke (BS), and sulphur dioxide (SO 2) was estimated. Exposure at each home address ( N=21 868) was considered as a function of a regional, an urban and a local component. The regional component was estimated using inverse distance weighed interpolation of measurement data from regional background sites in a national monitoring network. Regression models with urban concentrations as dependent variables, and number of inhabitants in different buffers and land use variables, derived with a Geographic Information System (GIS), as predictor variables were used to estimate the urban component. The local component was assessed using a GIS and a digital road network with linked traffic intensities. Traffic intensity on the nearest road and on the nearest major road, and the sum of traffic intensity in a buffer of 100 m around each home address were assessed. Further, a quantitative estimate of the local component was estimated. The regression models to estimate the urban component explained 67%, 46%, 49% and 35% of the variances of NO 2, NO, BS, and SO 2 concentrations, respectively. Overall regression models which incorporated the regional, urban and local component explained 84%, 44%, 59% and 56% of the variability in concentrations for NO 2, NO, BS and SO 2, respectively. We were able to develop an exposure assessment model using GIS methods and traffic intensities that explained a large part of the variations in outdoor air pollution concentrations.

Development of Public Rail Track Transport in Nord-Western Area of Bratislava

NASA Astrophysics Data System (ADS)

Koštial, Matej; Schlosser, Tibor; Schlosser, Peter

2017-10-01

The article deals with the development plans and possibilities of the Bratislava north-west expansion direction. Its focus is on the sites in the Lamačská Brána area - Bory and CENTROP - which with their size of approximately 817 hectares are owned by two major developers. The article describes variants of possible rail transport system extension, as it is classified as the cordial system of public transport by the Bratislava urban planning documentation. The traffic service proposal deals with the new traffic infrastructure on given future and realised locations and generates input for the traffic planning itself, which will define the build intensity restriction using the traffic model. Particular variants of the rail transport in given area are proposed to be the primary tool for future area development possibility. Along with the urban tram with narrow gauge of 1000 mm defined in urban planning documentation, the area service is considered by the introduced standard gauge (1435 mm) tram-train track connected to the international railway link. This track is intended to be a part of the integrated suburban public transport system aiming to access the satellite town Stupava inside the Bratislava city agglomeration.

Modeling and formal analysis of urban road traffic

NASA Astrophysics Data System (ADS)

Avram, Camelia; Machado, José; Aştilean, Adina

2013-10-01

Modern life in cities leads to complex urban traffic road and, sometimes, to go from one point to another, in a city, is a hard and very complex task. The use of assisted systems for helping drivers on their task of reaching the desired destination is being common, mainly systems like GPS location systems or other similar systems. The main gap of those systems is that they are not able to assist drivers when some unexpected changes occur, like accidents, or another unexpected situations. In this context, it would be desirable to have a dynamic system to inform the drivers, about everything that is happening "online". This work is inserted in this context and the work presented here is one part of a bigger project that has, as main goal, to be a dynamic system for assisting drivers under hard conditions of urban road traffic. In this paper is modeled, and formally analyzed, the intersection of four street segments, in order to take some considerations about this subject. This paper presents the model of the considered system, using timed automata formalism. The validation and verification of the road traffic model it is realized using UPPAAL model-checker.

Urban traffic-related determinants of health questionnaire (UTDHQ): an instrument developed for health impact assessments.

PubMed

Nadrian, Haidar; Nedjat, Saharnaz; Taghdisi, Mohammad Hossein; Shojaeizadeh, Davoud

2014-01-01

Traffic and transport is a substantial part of a range of economic, social and environmental factors distinguished to have impact on human health. This paper is a report on a preliminary section of a Health Impact Assessment (HIA) on urban traffic and transport initiatives, being conducted in Sanandaj, Iran. In this preliminary study, the psychometric properties of Urban Traffic related Determinants of Health Questionnaire (UTDHQ) were investigated. Multistage cluster sampling was employed to recruit 476 key informants in Sanandaj from April to June 2013 to participate in the study. The development of UTDHQ began with a comprehensive review of the literature. Then face, content and construct validity as well as reliability were determined. Exploratory Factor Analysis showed optimal reduced solution including 40 items and 8 factors. Three of the factors identified were Physical Environment, Social Environment, Public Services Delivery and Accessibility. UTDHQ demonstrated an appropriate validity, reliability, functionality and simplicity. Despite the need for further studies on UTDHQ, this study showed that it can be a practical and useful tool for conducting HIAs in order to inform decision makers and stakeholders about the health influences of their decisions and measures.

Urban Growth Modeling Using AN Artificial Neural Network a Case Study of Sanandaj City, Iran

NASA Astrophysics Data System (ADS)

Mohammady, S.; Delavar, M. R.; Pahlavani, P.

2014-10-01

Land use activity is a major issue and challenge for town and country planners. Modelling and managing urban growth is a complex problem. Cities are now recognized as complex, non-linear and dynamic process systems. The design of a system that can handle these complexities is a challenging prospect. Local governments that implement urban growth models need to estimate the amount of urban land required in the future given anticipated growth of housing, business, recreation and other urban uses within the boundary. There are so many negative implications related with the type of inappropriate urban development such as increased traffic and demand for mobility, reduced landscape attractively, land use fragmentation, loss of biodiversity and alterations of the hydrological cycle. The aim of this study is to use the Artificial Neural Network (ANN) to make a powerful tool for simulating urban growth patterns. Our study area is Sanandaj city located in the west of Iran. Landsat imageries acquired at 2000 and 2006 are used. Dataset were used include distance to principle roads, distance to residential areas, elevation, slope, distance to green spaces and distance to region centers. In this study an appropriate methodology for urban growth modelling using satellite remotely sensed data is presented and evaluated. Percent Correct Match (PCM) and Figure of Merit were used to evaluate ANN results.

Multi-level Bayesian safety analysis with unprocessed Automatic Vehicle Identification data for an urban expressway.

PubMed

Shi, Qi; Abdel-Aty, Mohamed; Yu, Rongjie

2016-03-01

In traffic safety studies, crash frequency modeling of total crashes is the cornerstone before proceeding to more detailed safety evaluation. The relationship between crash occurrence and factors such as traffic flow and roadway geometric characteristics has been extensively explored for a better understanding of crash mechanisms. In this study, a multi-level Bayesian framework has been developed in an effort to identify the crash contributing factors on an urban expressway in the Central Florida area. Two types of traffic data from the Automatic Vehicle Identification system, which are the processed data capped at speed limit and the unprocessed data retaining the original speed were incorporated in the analysis along with road geometric information. The model framework was proposed to account for the hierarchical data structure and the heterogeneity among the traffic and roadway geometric data. Multi-level and random parameters models were constructed and compared with the Negative Binomial model under the Bayesian inference framework. Results showed that the unprocessed traffic data was superior. Both multi-level models and random parameters models outperformed the Negative Binomial model and the models with random parameters achieved the best model fitting. The contributing factors identified imply that on the urban expressway lower speed and higher speed variation could significantly increase the crash likelihood. Other geometric factors were significant including auxiliary lanes and horizontal curvature. Copyright © 2015 Elsevier Ltd. All rights reserved.

An Intelligent Cooperative Visual Sensor Network for Urban Mobility

PubMed Central

Leone, Giuseppe Riccardo; Petracca, Matteo; Salvetti, Ovidio; Azzarà, Andrea

2017-01-01

Smart cities are demanding solutions for improved traffic efficiency, in order to guarantee optimal access to mobility resources available in urban areas. Intelligent video analytics deployed directly on board embedded sensors offers great opportunities to gather highly informative data about traffic and transport, allowing reconstruction of a real-time neat picture of urban mobility patterns. In this paper, we present a visual sensor network in which each node embeds computer vision logics for analyzing in real time urban traffic. The nodes in the network share their perceptions and build a global and comprehensive interpretation of the analyzed scenes in a cooperative and adaptive fashion. This is possible thanks to an especially designed Internet of Things (IoT) compliant middleware which encompasses in-network event composition as well as full support of Machine-2-Machine (M2M) communication mechanism. The potential of the proposed cooperative visual sensor network is shown with two sample applications in urban mobility connected to the estimation of vehicular flows and parking management. Besides providing detailed results of each key component of the proposed solution, the validity of the approach is demonstrated by extensive field tests that proved the suitability of the system in providing a scalable, adaptable and extensible data collection layer for managing and understanding mobility in smart cities. PMID:29125535

An Intelligent Cooperative Visual Sensor Network for Urban Mobility.

PubMed

Leone, Giuseppe Riccardo; Moroni, Davide; Pieri, Gabriele; Petracca, Matteo; Salvetti, Ovidio; Azzarà, Andrea; Marino, Francesco

2017-11-10

Smart cities are demanding solutions for improved traffic efficiency, in order to guarantee optimal access to mobility resources available in urban areas. Intelligent video analytics deployed directly on board embedded sensors offers great opportunities to gather highly informative data about traffic and transport, allowing reconstruction of a real-time neat picture of urban mobility patterns. In this paper, we present a visual sensor network in which each node embeds computer vision logics for analyzing in real time urban traffic. The nodes in the network share their perceptions and build a global and comprehensive interpretation of the analyzed scenes in a cooperative and adaptive fashion. This is possible thanks to an especially designed Internet of Things (IoT) compliant middleware which encompasses in-network event composition as well as full support of Machine-2-Machine (M2M) communication mechanism. The potential of the proposed cooperative visual sensor network is shown with two sample applications in urban mobility connected to the estimation of vehicular flows and parking management. Besides providing detailed results of each key component of the proposed solution, the validity of the approach is demonstrated by extensive field tests that proved the suitability of the system in providing a scalable, adaptable and extensible data collection layer for managing and understanding mobility in smart cities.

Impacts of moving bottlenecks on traffic flow

NASA Astrophysics Data System (ADS)

Ou, Hui; Tang, Tie-Qiao

2018-06-01

Bottleneck (especially the moving bottleneck) widely exists in the urban traffic system. However, little effort has been made to study the impacts of the moving bottleneck on traffic flow (especially the evolution and propagation of traffic flow). In this article, we introduce the speed of a moving bottleneck into a traffic flow model, then propose an extended macro traffic flow with a moving bottleneck, and finally use the proposed model to study the effects of a moving bottleneck on the evolution and propagation of traffic flow under uniform flow and a small perturbation. The numerical results indicate that the moving bottleneck has prominent influences on the evolution of traffic flow under the two typical traffic situations and that the impacts are dependent on the initial density.

Inspections of Interstate Commercial Vehicles 1994

DOT National Transportation Integrated Search

1974-01-01

The objective of this effort was to complete the development of the computer simulation model SCOT (Simulation of Corridor Traffic) designed to represent traffic flow on an urban grid-freeway integrated highway system by simulating an existing system...

Interstate 64 traffic response assessment : staff summary.

DOT National Transportation Integrated Search

2009-12-01

An evaluation was conducted of the implemented mobility strategy on the New I-64 : construction project. This construction project will improve more than 10 miles of an : urban Interstate that carries daily traffic volumes approaching 170,000 vehicle...

Toolbox for Urban Mobility Simulation: High Resolution Population Dynamics for Global Cities

NASA Astrophysics Data System (ADS)

Bhaduri, B. L.; Lu, W.; Liu, C.; Thakur, G.; Karthik, R.

2015-12-01

In this rapidly urbanizing world, unprecedented rate of population growth is not only mirrored by increasing demand for energy, food, water, and other natural resources, but has detrimental impacts on environmental and human security. Transportation simulations are frequently used for mobility assessment in urban planning, traffic operation, and emergency management. Previous research, involving purely analytical techniques to simulations capturing behavior, has investigated questions and scenarios regarding the relationships among energy, emissions, air quality, and transportation. Primary limitations of past attempts have been availability of input data, useful "energy and behavior focused" models, validation data, and adequate computational capability that allows adequate understanding of the interdependencies of our transportation system. With increasing availability and quality of traditional and crowdsourced data, we have utilized the OpenStreetMap roads network, and has integrated high resolution population data with traffic simulation to create a Toolbox for Urban Mobility Simulations (TUMS) at global scale. TUMS consists of three major components: data processing, traffic simulation models, and Internet-based visualizations. It integrates OpenStreetMap, LandScanTM population, and other open data (Census Transportation Planning Products, National household Travel Survey, etc.) to generate both normal traffic operation and emergency evacuation scenarios. TUMS integrates TRANSIMS and MITSIM as traffic simulation engines, which are open-source and widely-accepted for scalable traffic simulations. Consistent data and simulation platform allows quick adaption to various geographic areas that has been demonstrated for multiple cities across the world. We are combining the strengths of geospatial data sciences, high performance simulations, transportation planning, and emissions, vehicle and energy technology development to design and develop a simulation framework to assist decision makers at all levels - local, state, regional, and federal. Using Cleveland, Tennessee as an example, in this presentation, we illustrate how emerging cities could easily assess future land use scenario driven impacts on energy and environment utilizing such a capability.

Real-world emission factors of fine and ultrafine aerosol particles for different traffic situations in Switzerland.

PubMed

Imhof, David; Weingartner, Ernest; Ordónez, Carlos; Gehrig, Robert; Hill, Matz; Buchmann, Brigitte; Baltensperger, Urs

2005-11-01

Extended field measurements of particle number (size distribution of particle diameters, D, in the range between 18 nm and 10 microm), surface area concentrations, and PM1 and PM10 mass concentrations were performed in Switzerland to determine traffic emissions using a comprehensive set of instruments. Measurements took place at roads with representative traffic regimes: at the kerbside of a motorway (120 km h(-1)), a highway (80-100 km h(-1)), and in an urban area with stop-and-go traffic (0-50 km h(-1)) regulated by light signals. Mean diurnal variations showed that the highest pollutant concentrations were during the morning rush hours, especially of the number density in the nanoparticle size range (D <50 nm). From the differences between up- and downwind concentrations (or differences between kerbside and background concentrations for the urban site), "real-life" emission factors were derived using NOx concentrations to calculate dilution factors. Particle number and volume emission factors of different size ranges (18-50 nm, 18-100 nm, and 18-300 nm) were derived for the total vehicle fleet and separated into a light-duty (LDV) and a heavy-duty vehicle (HDV) contribution. The total particle number emissions per vehicle were found to be about 11.7-13.5 x 10(14) particles km(-1) for constant speed (80-120 km h(-1) and 3.9 x 10(14) particles km(-1) for urban driving conditions. LDVs showed higher emission factors at constant high speed than under urban disturbed traffic flow. In contrast, HDVs emitted more air pollutants during deceleration and acceleration processes in stop-and-go traffic than with constant speed of about 80 km h(-1). On average, one HDV emits a 10-30 times higher amount of particulate air pollutants (in terms of both number and volume) than one LDV.

Distribution of heavy metals in road dust along an urban-rural gradient in Massachusetts

NASA Astrophysics Data System (ADS)

Apeagyei, Eric; Bank, Michael S.; Spengler, John D.

2011-04-01

Human exposures to particulate matter emitted from on-road motor vehicles include complex mixtures of metals from tires, brakes, parts wear and resuspended road dust. The aim of this study was to assess road dust for metals associated with motor vehicle traffic, particularly those metals coming from brake and tire wears. We hypothesized that the road dust would show significant difference in both composition and concentration by traffic type, road class and by location. X-ray fluorescence (XRF) analyses of 115 parked car tires showed Zn and Ca were likely associated with tire wear dust. XRF results of three used brake pads indicated high concentrations of Fe, Ti, Cu, Ba, Mo and Zr. To assess heavy metal exposures associated with tires and brake wear adjacent to roads of varying traffic and functional classes, 85 samples of road dust were collected from road surfaces adjacent to the curb and analyzed by XRF. Median concentrations for Fe, Ca and K were greater than Ti (1619 ppm), with concentration ratios of Fe: Ca: K: Ti [16:5:3:1]. Cumulative frequency distribution graphs showed distribution of Fe, Ba, Cu, and Mo were similar regardless of road traffic rating. However, Zn, Ti, and Zr varied significantly ( p < 0.05) with traffic ratings of roadways (heavy > moderate > low traffic). Fe, Ba, Cu, and Mo also had similar distributions regardless of road class while composition of Zn, Ti, and Zr varied significantly across road class ( p < 0.05) (Major roads > Minor roads > highway). In comparing urban road dust to rural road dust, we observed Fe, Ca, K, and Ti were significantly greater in urban road dust ( p < 0.05). In urban road dust the Fe: Ca: K: Ti relationship with median Ti of 2216 ppm was 12: 6: 3.5: 1. These results indicate that roadway dust may be important sources of metals for runoff water and localized resuspended particulate matter.

Planning the City Logistics Terminal Location by Applying the Green p-Median Model and Type-2 Neurofuzzy Network

PubMed Central

Pamučar, Dragan; Vasin, Ljubislav; Atanasković, Predrag; Miličić, Milica

2016-01-01

The paper herein presents green p-median problem (GMP) which uses the adaptive type-2 neural network for the processing of environmental and sociological parameters including costs of logistics operators and demonstrates the influence of these parameters on planning the location for the city logistics terminal (CLT) within the discrete network. CLT shows direct effects on increment of traffic volume especially in urban areas, which further results in negative environmental effects such as air pollution and noise as well as increased number of urban populations suffering from bronchitis, asthma, and similar respiratory infections. By applying the green p-median model (GMM), negative effects on environment and health in urban areas caused by delivery vehicles may be reduced to minimum. This model creates real possibilities for making the proper investment decisions so as profitable investments may be realized in the field of transport infrastructure. The paper herein also includes testing of GMM in real conditions on four CLT locations in Belgrade City zone. PMID:27195005

Planning the City Logistics Terminal Location by Applying the Green p-Median Model and Type-2 Neurofuzzy Network.

PubMed

Pamučar, Dragan; Vasin, Ljubislav; Atanasković, Predrag; Miličić, Milica

2016-01-01

The paper herein presents green p-median problem (GMP) which uses the adaptive type-2 neural network for the processing of environmental and sociological parameters including costs of logistics operators and demonstrates the influence of these parameters on planning the location for the city logistics terminal (CLT) within the discrete network. CLT shows direct effects on increment of traffic volume especially in urban areas, which further results in negative environmental effects such as air pollution and noise as well as increased number of urban populations suffering from bronchitis, asthma, and similar respiratory infections. By applying the green p-median model (GMM), negative effects on environment and health in urban areas caused by delivery vehicles may be reduced to minimum. This model creates real possibilities for making the proper investment decisions so as profitable investments may be realized in the field of transport infrastructure. The paper herein also includes testing of GMM in real conditions on four CLT locations in Belgrade City zone.

Bayes classifiers for imbalanced traffic accidents datasets.

PubMed

Mujalli, Randa Oqab; López, Griselda; Garach, Laura

2016-03-01

Traffic accidents data sets are usually imbalanced, where the number of instances classified under the killed or severe injuries class (minority) is much lower than those classified under the slight injuries class (majority). This, however, supposes a challenging problem for classification algorithms and may cause obtaining a model that well cover the slight injuries instances whereas the killed or severe injuries instances are misclassified frequently. Based on traffic accidents data collected on urban and suburban roads in Jordan for three years (2009-2011); three different data balancing techniques were used: under-sampling which removes some instances of the majority class, oversampling which creates new instances of the minority class and a mix technique that combines both. In addition, different Bayes classifiers were compared for the different imbalanced and balanced data sets: Averaged One-Dependence Estimators, Weightily Average One-Dependence Estimators, and Bayesian networks in order to identify factors that affect the severity of an accident. The results indicated that using the balanced data sets, especially those created using oversampling techniques, with Bayesian networks improved classifying a traffic accident according to its severity and reduced the misclassification of killed and severe injuries instances. On the other hand, the following variables were found to contribute to the occurrence of a killed causality or a severe injury in a traffic accident: number of vehicles involved, accident pattern, number of directions, accident type, lighting, surface condition, and speed limit. This work, to the knowledge of the authors, is the first that aims at analyzing historical data records for traffic accidents occurring in Jordan and the first to apply balancing techniques to analyze injury severity of traffic accidents. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation of traffic exhaust contributions to ambient carbonaceous submicron particulate matter in an urban roadside environment in Hong Kong

NASA Astrophysics Data System (ADS)

Lee, Berto Paul; Kwok Keung Louie, Peter; Luk, Connie; Keung Chan, Chak

2017-12-01

Road traffic has significant impacts on air quality particularly in densely urbanized and populated areas where vehicle emissions are a major local source of ambient particulate matter. Engine type (i.e., fuel use) significantly impacts the chemical characteristics of tailpipe emission, and thus the distribution of engine types in traffic impacts measured ambient concentrations. This study provides an estimation of the contribution of vehicles powered by different fuels (gasoline, diesel, LPG) to carbonaceous submicron aerosol mass (PM1) based on ambient aerosol mass spectrometer (AMS) and elemental carbon (EC) measurements and vehicle count data in an urban inner city environment in Hong Kong with the aim to gauge the importance of different engine types to particulate matter burdens in a typical urban street canyon. On an average per-vehicle basis, gasoline vehicles emitted 75 and 93 % more organics than diesel and LPG vehicles, respectively, while EC emissions from diesel vehicles were 45 % higher than those from gasoline vehicles. LPG vehicles showed no appreciable contributions to EC and thus overall represented a small contributor to traffic-related primary ambient PM1 despite their high abundance (˜ 30 %) in the traffic mix. Total carbonaceous particle mass contributions to ambient PM1 from diesel engines were only marginally higher (˜ 4 %) than those from gasoline engines, which is likely an effect of recently introduced control strategies targeted at commercial vehicles and buses. Overall, gasoline vehicles contributed 1.2 µg m-3 of EC and 1.1 µ m-3 of organics, LPG vehicles 0.6 µg m-3 of organics and diesel vehicles 2.0 µg m-3 of EC and 0.7 µg m-3 of organics to ambient carbonaceous PM1.

The traffic crisis and a tale of two cities: Traffic and air quality in Bangkok and Mexico City

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pendakur, V.S.; Badami, M.G.

1995-12-31

This paper focuses on congestion management techniques, traffic congestion levels and air quality. By using data from Bangkok and Mexico City, it illustrates the need for drastic changes in transportation policy tools and techniques for congestion management and for improving environmental quality. New approaches to investment and regulatory policy analysis and implementation are suggested. This requires the inclusion of all costs and benefits (economic and ecological) in the policy matrix so that investment and regulatory policies act in unison. Megacities are dominant in social, political and economic terms. 30 to 60% of national GDP is typically produced in these cities.more » Their human and motor vehicle populations have been doubling every 15-20 and 6-10 years respectively. They also have the most severe traffic congestion and air quality problems. They have the nation`s highest incidence of poverty and absolute poverty. Large portions of their populations endure severely unhealthy housing and sanitation conditions. Following are important characteristics of urban transportation systems in the megacities: the city centres are heavily congested with motorized traffic; traffic crawl rates vary from 2 to 10 km/hr; car and motorcycle ownership are increasing at annual rates of 10-12% and 15-20% respectively; significant air pollution with no relief in sight; TDM strategies are primarily creating new supply of road capacity; fairly high transit trips with substantial transit investments; weak air pollution monitoring and enforcement; and fairly cheap fuel and high costs of vehicles.« less

An estimation of vehicle kilometer traveled and on-road emissions using the traffic volume and travel speed on road links in Incheon City.

PubMed

Jung, Sungwoon; Kim, Jounghwa; Kim, Jeongsoo; Hong, Dahee; Park, Dongjoo

2017-04-01

The objective of this study is to estimate the vehicle kilometer traveled (VKT) and on-road emissions using the traffic volume in urban. We estimated two VKT; one is based on registered vehicles and the other is based on traffic volumes. VKT for registered vehicles was 2.11 times greater than that of the applied traffic volumes because each VKT estimation method is different. Therefore, we had to define the inner VKT is moved VKT inner in urban to compare two values. Also, we focused on freight modes because these are discharged much air pollutant emissions. From analysis results, we found middle and large trucks registered in other regions traveled to target city in order to carry freight, target city has included many industrial and logistics areas. Freight is transferred through the harbors, large logistics centers, or via locations before being moved to the final destination. During this process, most freight is moved by middle and large trucks, and trailers rather than small trucks for freight import and export. Therefore, these trucks from other areas are inflow more than registered vehicles. Most emissions from diesel trucks had been overestimated in comparison to VKT from applied traffic volumes in target city. From these findings, VKT is essential based on traffic volume and travel speed on road links in order to estimate accurately the emissions of diesel trucks in target city. Our findings support the estimation of the effect of on-road emissions on urban air quality in Korea. Copyright © 2016. Published by Elsevier B.V.

Heavy metal pollution in Nanchang City and its health implication on traffic policemen.

PubMed

Liu, Xiaozhen; Liang, Yue; Guo, Jiangmei

2017-09-27

The purpose of this study is to evaluate the health effect of heavy metal pollution in air pollutants on traffic policemen. This study will facilitate the scientific evaluation of health status of traffic policemen. PM 10 samples were collected from industrial area, congested traffic area and residential area respectively in Nanchang City, and the concentrations of heavy metals were analyzed. The traffic policemen were examined through chest X-rays. The total of 637 urine samples and 142 blood samples have been collected, and the concentrations of Pb in samples were detected. Vehicle flux data of Nanchang City were collected from the Department of Transport's Traffic Management. Statistic analyses were carried out by statistics software of Excel 2003 and SPSS20.0, and the health effect of heavy metal pollution of PM 10 on the traffic policemen was evaluated. The discharge of pollutants from enterprises is an important reason for the high content of heavy metals in urban air pollution. With the rapid growth of urban traffic flow, Bayi Bridge becomes an important transportation hinge in Nanchang City, and the bidirectional traffic flow rate through the bridge at peak hours reached 99 vehicles per minute. The latent hazard of occupational harm on the traffic policemen caused by automobile exhaust is increasing. The concentration of Pb in the urine and blood samples from traffic policemen working in Nanchang City was 268.310 ± 177.031 and 22.873 ± 21.137 μg/L, respectively. Both results (2.04% of Pb in urine and 18.31% of Pb in blood) exceeded the highest limit of observed occupationally outdoor workers. This study provides an initial contribution for the assessment of city air pollution, esp. the health effect of heavy metal (Pb) pollution on traffic policemen.

Alternative approaches to condition monitoring in freeway management systems.

DOT National Transportation Integrated Search

2002-01-01

In response to growing concerns over traffic congestion, traffic management systems have been built in large urban areas in an effort to improve the efficiency and safety of the transportation network. This research effort developed an automated cond...

Effects of street traffic noise in the night

NASA Technical Reports Server (NTRS)

Wehrli, B.; Nemecek, J.; Turrian, V.; Hoffman, R.; Wanner, H.

1980-01-01

The relationship between automobile traffic noise and the degree of disturbance experience experienced at night was explored through a random sample survey of 1600 individuals in rural and urban areas. The data obtained were used to establish threshold values.

Evaluation of pre-emption and transition strategies for Northern Virginia Smart Traffic Signal Systems (NVSTSS).

DOT National Transportation Integrated Search

2008-01-01

Modern traffic signal control systems provide emergency vehicle preemption (EVP) capabilities by utilizing advanced sensors and communication technologies. EVP strategies are widely implemented by urban transportation management agencies. One of the ...

Revision to the SUDAS traffic signal standards : phase 2.

DOT National Transportation Integrated Search

2012-05-01

This report provides a summary of the updates to the traffic signal content within the Iowa Statewide Urban Design and Specifications : (SUDAS) Design Manual Chapter 13 and Standard Specifications Division 8. Major focal points included pole footing ...

Estimate of main local sources to ambient ultrafine particle number concentrations in an urban area

NASA Astrophysics Data System (ADS)

Rahman, Md Mahmudur; Mazaheri, Mandana; Clifford, Sam; Morawska, Lidia

2017-09-01

Quantifying and apportioning the contribution of a range of sources to ultrafine particles (UFPs, D < 100 nm) is a challenge due to the complex nature of the urban environments. Although vehicular emissions have long been considered one of the major sources of ultrafine particles in urban areas, the contribution of other major urban sources is not yet fully understood. This paper aims to determine and quantify the contribution of local ground traffic, nucleated particle (NP) formation and distant non-traffic (e.g. airport, oil refineries, and seaport) sources to the total ambient particle number concentration (PNC) in a busy, inner-city area in Brisbane, Australia using Bayesian statistical modelling and other exploratory tools. The Bayesian model was trained on the PNC data on days where NP formations were known to have not occurred, hourly traffic counts, solar radiation data, and smooth daily trend. The model was applied to apportion and quantify the contribution of NP formations and local traffic and non-traffic sources to UFPs. The data analysis incorporated long-term measured time-series of total PNC (D ≥ 6 nm), particle number size distributions (PSD, D = 8 to 400 nm), PM2.5, PM10, NOx, CO, meteorological parameters and traffic counts at a stationary monitoring site. The developed Bayesian model showed reliable predictive performances in quantifying the contribution of NP formation events to UFPs (up to 4 × 104 particles cm- 3), with a significant day to day variability. The model identified potential NP formation and no-formations days based on PNC data and quantified the sources contribution to UFPs. Exploratory statistical analyses show that total mean PNC during the middle of the day was up to 32% higher than during peak morning and evening traffic periods, which were associated with NP formation events. The majority of UFPs measured during the peak traffic and NP formation periods were between 30-100 nm and smaller than 30 nm, respectively. To date, this is the first application of Bayesian model to apportion different sources contribution to UFPs, and therefore the importance of this study is not only in its modelling outcomes but in demonstrating the applicability and advantages of this statistical approach to air pollution studies.

A modified 3D algorithm for road traffic noise attenuation calculations in large urban areas.

PubMed

Wang, Haibo; Cai, Ming; Yao, Yifan

2017-07-01

The primary objective of this study is the development and application of a 3D road traffic noise attenuation calculation algorithm. First, the traditional empirical method does not address problems caused by non-direct occlusion by buildings and the different building heights. In contrast, this study considers the volume ratio of the buildings and the area ratio of the projection of buildings adjacent to the road. The influence of the ground affection is analyzed. The insertion loss due to barriers (infinite length and finite barriers) is also synthesized in the algorithm. Second, the impact of different road segmentation is analyzed. Through the case of Pearl River New Town, it is recommended that 5° is the most appropriate scanning angle as the computational time is acceptable and the average error is approximately 3.1 dB. In addition, the algorithm requires only 1/17 of the time that the beam tracking method requires at the cost of more imprecise calculation results. Finally, the noise calculation for a large urban area with a high density of buildings shows the feasibility of the 3D noise attenuation calculation algorithm. The algorithm is expected to be applied in projects requiring large area noise simulations. Copyright © 2017 Elsevier Ltd. All rights reserved.

Building statistical associations to forecast ethylbenzene levels in European urban-traffic environments.

PubMed

Vlachokostas, Ch; Michailidou, A V; Spyridi, D; Moussiopoulos, N

2013-06-01

Emission from road traffic has become the most important source of local air pollution in numerous European cities. Epidemiological research community has established consistent associations between traffic-related substances and various health outcomes. Nevertheless, the vast majority of urban areas are characterised by infrastructure's absence to routinely monitor chemical health stressors, such as ethylbenzene. This paper aims at developing and presenting a tractable approach to reliably - and inexpensively - predict ethylbenzene trends in EU urban environments. The establishment of empirical relationships between rarely monitored pollutants such as ethylbenzene and more frequently or usually monitored, such as benzene and CO respectively, may cover the infrastructure's absence and support decision-making. Multiple regression analysis is adopted and the resulting statistical associations are applied to EU cities with available data for validation purposes. The results demonstrate that this approach is capable of capturing ethylbenzene concentration trends and should be considered as complementary to air quality monitoring. Copyright © 2013 Elsevier Ltd. All rights reserved.

Factors associated with urban non-fatal road-accident severity.

PubMed

Potoglou, Dimitris; Carlucci, Fabio; Cirà, Andrea; Restaino, Marialuisa

2018-02-05

This paper reports on the factors associated with non-fatal urban-road accident severity. Data on accidents were gathered from the local traffic police in the City of Palermo, one of the six most populated cities in Italy. Findings from a mixed-effects logistic-regression model suggest that accident severity increases when two young drivers are involved, road traffic conditions are light/normal and when vehicles crash on a two-way road or carriageway. Speeding is more likely to cause slight or serious injury even when compared to a vehicle moving towards the opposite direction of traffic. An accident during the summer is more likely to result in a slight or serious injury than an accident during the winter, which is in line with evidence from Southern Europe and the Middle East. Finally, the severity of non-fatal accident injuries in an urban area of Southern Europe was significantly associated with speeding, the age of the driver and seasonality.

Land use mapping and change detection using ERTS imagery in Montgomery County, Alabama

NASA Technical Reports Server (NTRS)

Wilms, R. P.

1973-01-01

The feasibility of using remotely sensed data from ERTS-1 for mapping land use and detecting land use change was investigated. Land use information was gathered from 1964 air photo mosaics and from 1972 ERTS data. The 1964 data provided the basis for comparison with ERTS-1 imagery. From this comparison, urban sprawl was quite evident for the city of Montgomery. A significant trend from forestland to agricultural was also discovered. The development of main traffic arteries between 1964 and 1972 was a vital factor in the development of some of the urban centers. Even though certain problems in interpreting and correlating land use data from ERTS imagery were encountered, it has been demonstrated that remotely sensed data from ERTS is useful for inventorying land use and detecting land use change.

Association between prenatal exposure to traffic-related air pollution and preterm birth in the PELAGIE mother-child cohort, Brittany, France. Does the urban-rural context matter?

PubMed

Bertin, Mélanie; Chevrier, Cécile; Serrano, Tania; Monfort, Christine; Rouget, Florence; Cordier, Sylvaine; Viel, Jean-François

2015-10-01

Evidence has accumulated that exposure to ambient air pollution during pregnancy may influence preterm birth (PTB) in urban settings. Conversely, this relation has barely been investigated in rural areas where individual characteristics (demographic, socioeconomic, and psychosocial factors) and environmental co-exposures may differ. We examined the association between prenatal exposure to traffic-related air pollution and PTB among pregnant women from the PELAGIE mother-child cohort (Brittany, France, 2002-2006) living in urban (n=1550) and rural (n=959) settings. Women's residences were classified as either urban or rural according to the French census bureau rural-urban definitions. Nitrogen dioxide (NO2) concentrations at home addresses were estimated from adjusted land-use regression models as a marker of traffic-related pollution. Associations between NO2 concentrations and PTB were assessed with logistic regression models. Prevalence of PTB was similar among women living in urban (3.2%) and in rural (3.5%) settings. More positive socioeconomic characteristics and health behaviors but more single-parent families were observed among urban women. NO2 exposure averaged 20.8±6.6 µg m(-3) for women residing in urban areas and 18.8±5.6 µg m(-3) for their rural counterparts. A statistically significant increased risk of PTB was observed among women exposed to NO2 concentrations ≥16.4 µg m(-3) and residing in urban areas but not among their rural counterparts. The results of this study, conducted in a region with interspersed urban-rural areas, are in line with previous findings suggesting an increased risk of PTB associated with higher NO2 concentrations for women living in urban areas. The absence of association among their rural counterparts for whom exposure levels were similar suggests that environmental mixtures and psychosocial inequalities might play a role in this heterogeneity. Copyright © 2015 Elsevier Inc. All rights reserved.

Building a Multivariable Linear Regression Model of On-road Traffic for Creation of High Resolution Emission Inventories

NASA Astrophysics Data System (ADS)

Powell, James Eckhardt

Emissions inventories are an important tool, often built by governments, and used to manage emissions. To build an inventory of urban CO2 emissions and other fossil fuel combustion products in the urban atmosphere, an inventory of on-road traffic is required. In particular, a high resolution inventory is necessary to capture the local characteristics of transport emissions. These emissions vary widely due to the local nature of the fleet, fuel, and roads. Here we show a new model of ADT for the Portland, OR metropolitan region. The backbone is traffic counter recordings made by the Portland Bureau of Transportation at 7,767 sites over 21 years (1986-2006), augmented with PORTAL (The Portland Regional Transportation Archive Listing) freeway traffic count data. We constructed a regression model to fill in traffic network gaps using GIS data such as road class and population density. An EPA-supplied emissions factor was used to estimate transportation CO2 emissions, which is compared to several other estimates for the city's CO2 footprint.

Economic impact of traffic incidents on North Carolina's interstate facilities : final report, January 2008.

DOT National Transportation Integrated Search

2008-01-01

Unexpected delays due to traffic incidents represent a significant proportion of overall delay, especially in urban areas. The resulting uncertainty can represent major costs to businesses and travelers, as well as restrict employment opportunities. ...

Roadway usage patterns : urban case studies - final report

DOT National Transportation Integrated Search

1996-01-01

The Orlando Test Network Study was one of a series of investigations conducted as part of the TravTek operational test of an advanced traveler information and traffic management system (ATIS/ATMS). The TravTek system consisted of the Orlando Traffic ...

Operations and safety of Super 2 corridors with higher volumes.

DOT National Transportation Integrated Search

2011-06-01

As traffic volumes increase, in both urban and rural areas, the demand on the highway network also : increases. Specifically, as rural traffic volumes rise in Texas, the pressure on the states network of two-lane : highways rises accordingly. Prev...

Joor Road noise level assessment.

DOT National Transportation Integrated Search

2015-07-01

Joor Road (LA 946) is an Urban 5-lane Portland cement concrete roadway with an annual daily traffic (ADT) of approximately 13,500 with 7 percent : trucks and posted speed of 55 mph. Since being opened to traffic in 2009, residents have been complaini...

Real time driver information for congestion management.

DOT National Transportation Integrated Search

2015-07-01

Traffic demand in the U.S. has grown substantially over the past few years because of the increase in population and : urbanization in large cities. This causes traffic congestion to spread out over U.S. highways and arterials, and subsequently : lea...

A theoretical framework for the episodic-urban air quality management plan ( e-UAQMP)

NASA Astrophysics Data System (ADS)

Gokhale, Sharad; Khare, Mukesh

The present research proposes the local urban air quality management plan which combines two different modelling approaches (hybrid model) and possesses an improved predictive ability including the 'probabilistic exceedances over norms' and their 'frequency of occurrences' and so termed, herein, as episodic-urban air quality management plan ( e-UAQMP). The e-UAQMP deals with the consequences of 'extreme' concentrations of pollutant, mainly occurring at urban 'hotspots' e.g. traffic junctions, intersections and signalized roadways and are also influenced by complexities of traffic generated 'wake' effects. The e-UAQMP (based on probabilistic approach), also acts as an efficient preventive measure to predict the 'probability of exceedances' so as to prepare a successful policy responses in relation to the protection of urban environment as well as disseminating information to its sensitive 'receptors'. The e-UAQMP may be tailored to the requirements of the local area for the policy implementation programmes. The importance of such policy-making framework in the context of current air pollution 'episodes' in urban environments is discussed. The hybrid model that is based on both deterministic and stochastic based approaches predicting the 'average' as well as 'extreme' concentration distribution of air pollutants together in form of probability has been used at two air quality control regions (AQCRs) in the Delhi city, India, in formulating and executing the e-UAQMP— first, the income tax office (ITO), one of the busiest signalized traffic intersection and second, the Sirifort, one of the busiest signalized roadways.

Implementing and Simulating Dynamic Traffic Assignment with Intelligent Transportation Systems in Cube Avenue

NASA Technical Reports Server (NTRS)

Foytik, Peter; Robinson, Mike

2010-01-01

As urban populations and traffic congestion levels increase, effective use of information and communication tools and intelligent transportation systems as becoming increasingly important in order to maximize the efficiency of transportation networks. The appropriate placement and employment of these tools within a network is critical to their effectiveness. This presentation proposes and demonstrates the use of a commercial transportation simulation tool to simulate dynamic traffic assignment and rerouting to model route modifications as a result of traffic information.

Perfluorooctane sulfonate (PFOS) contamination of fish in urban lakes: a prioritization methodology for lake management.

PubMed

Xiao, Feng; Gulliver, John S; Simcik, Matt F

2013-12-15

The contamination of urban lakes by anthropogenic pollutants such as perfluorooctane sulfonate (PFOS) is a worldwide environmental problem. Large-scale, long-term monitoring of urban lakes requires careful prioritization of available resources, focusing efforts on potentially impaired lakes. Herein, a database of PFOS concentrations in 304 fish caught from 28 urban lakes was used for development of an urban-lake prioritization framework by means of exploratory data analysis (EDA) with the aid of a geographical information system. The prioritization scheme consists of three main tiers: preliminary classification, carried out by hierarchical cluster analysis; predictor screening, fulfilled by a regression tree method; and model development by means of a neural network. The predictive performance of the newly developed model was assessed using a training/validation splitting method and determined by an external validation set. The application of the model in the U.S. state of Minnesota identified 40 urban lakes that may contain elevated levels of PFOS; these lakes were not previously considered in PFOS monitoring programs. The model results also highlight ongoing industrial/commercial activities as a principal determinant of PFOS pollution in urban lakes, and suggest vehicular traffic as an important source and surface runoff as a primary pollution carrier. In addition, the EDA approach was further compared to a spatial interpolation method (kriging), and their advantages and disadvantages were discussed. Copyright © 2013 Elsevier Ltd. All rights reserved.

Application Analysis of BIM Technology in Metro Rail Transit

NASA Astrophysics Data System (ADS)

Liu, Bei; Sun, Xianbin

2018-03-01

With the rapid development of urban roads, especially the construction of subway rail transit, it is an effective way to alleviate urban traffic congestion. There are limited site space, complex resource allocation, tight schedule, underground pipeline complex engineering problems. BIM technology, three-dimensional visualization, parameterization, virtual simulation and many other advantages can effectively solve these technical problems. Based on the project of Shenzhen Metro Line 9, BIM technology is innovatively researched throughout the lifecycle of BIM technology in the context of the metro rail transit project rarely used at this stage. The model information file is imported into Navisworks for four-dimensional animation simulation to determine the optimum construction scheme of the shield machine. Subway construction management application platform based on BIM and private cloud technology, the use of cameras and sensors to achieve electronic integration, dynamic monitoring of the operation and maintenance of underground facilities. Make full use of the many advantages of BIM technology to improve the engineering quality and construction efficiency of the subway rail transit project and to complete the operation and maintenance.

Noise, air pollutants and traffic: continuous measurement and correlation at a high-traffic location in New York City.

PubMed

Ross, Zev; Kheirbek, Iyad; Clougherty, Jane E; Ito, Kazuhiko; Matte, Thomas; Markowitz, Steven; Eisl, Holger

2011-11-01

Epidemiological studies have linked both noise and air pollution to common adverse health outcomes such as increased blood pressure and myocardial infarction. In urban settings, noise and air pollution share important sources, notably traffic, and several recent studies have shown spatial correlations between noise and air pollution. The temporal association between these exposures, however, has yet to be thoroughly investigated despite the importance of time series studies in air pollution epidemiology and the potential that correlations between these exposures could at least partly confound statistical associations identified in these studies. An aethelometer, for continuous elemental carbon measurement, was co-located with a continuous noise monitor near a major urban highway in New York City for six days in August 2009. Hourly elemental carbon measurements and hourly data on overall noise levels and low, medium and high frequency noise levels were collected. Hourly average concentrations of fine particles and nitrogen oxides, wind speed and direction and car, truck and bus traffic were obtained from nearby regulatory monitors. Overall temporal patterns, as well as day-night and weekday-weekend patterns, were characterized and compared for all variables. Noise levels were correlated with car, truck, and bus traffic and with air pollutants. We observed strong day-night and weekday-weekend variation in noise and air pollutants and correlations between pollutants varied by noise frequency. Medium and high frequency noise were generally more strongly correlated with traffic and traffic-related pollutants than low frequency noise and the correlation with medium and high frequency noise was generally stronger at night. Correlations with nighttime high frequency noise were particularly high for car traffic (Spearman rho=0.84), nitric oxide (0.73) and nitrogen dioxide (0.83). Wind speed and direction mediated relationships between pollutants and noise. Noise levels are temporally correlated with traffic and combustion pollutants and correlations are modified by the time of day, noise frequency and wind. Our results underscore the potential importance of assessing temporal variation in co-exposures to noise and air pollution in studies of the health effects of these urban pollutants. Copyright © 2011 Elsevier Inc. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jacobson, L.N.

Traffic congestion and personal mobility preservation are the most challenging issues facing transportation professionals. From Phoenix to San Francisco to Washington, D.C., citizens are identifying transportation as their number one concern, outweighing issues such as pollution, overpopulation, unemployment, and crime. In the state of Washington, particularly in the greater Seattle area, congestion is likewise a major concern. In order to address the mobility problems facing the urban areas of Washington, the state initiated a new transportation research and implementation program in October 1987. The program is called Freeway and Arterial Management Effort (FAME). The focus of the program is discussedmore » by the author.« less

Air quality: from observation to applied studies

NASA Astrophysics Data System (ADS)

Weber, Christiane H.; Wania, Annett; Hirsch, Jacky; Bruse, Michael

2004-10-01

Air qualities studies in urban areas embrace several directions that are strongly associated with urban complexity. In the last centuries cities evolution implied changes in urbanization trends: urban sprawl has modified the relationship between cities and surroundings settlements. The existence and protection of urban green and open areas is promoted as a mean to improve the quality of life of their citizens and increase the satisfactory level of the inhabitants against pollution and noise adverse effects. This paper outlines the methods and approaches used in the EU research project Benefits of Urban Green Space (BUGS). The main target of BUGS is to assess the role of urban green spaces in alleviating the adverse effects of urbanization trends by developing an integrative methodology, ranging from participatory planning tools to numerical simulation models. The influence of urban structures on atmospheric pollutants distribution is investigated as a multi-scale problem ranging from micro to macro/regional scale. Traditionally, air quality models are applied on a single scale, seldom considering the joint effects of traffic network and urban development together. In BUGS, several numerical models are applied to cope with urban complexity and to provide quantitative and qualitative results. The differing input data requirements for the various models demanded a methodology which ensures a coherent data extraction and application procedure. In this paper, the stepwise procedure used for BUGS is presented after a general presentation of the research project and the models implied. A discussion part will highlight the statements induced by the choices made and a conclusive part bring to the stage some insights for future investigations.

SATURN (Situational Awareness Tool for Urban Responder Networks)

DTIC Science & Technology

2012-07-01

timeline. SATURN is applicable to a broad set of law enforcement, security, and counterterrorism missions typically addressed by urban responders...Keywords-video analytics; sensor fusion; video; urban responders I. INTRODUCTION Urban authorities have a broad set of missions . Duties vary in...both the frequency of occurrence and in the complexity of execution. They include everyday public safety missions such as traffic enforcement as

Acoustic, Visual and Spatial Indicators for the Description of the Soundscape of Waterfront Areas with and without Road Traffic Flow.

PubMed

Puyana Romero, Virginia; Maffei, Luigi; Brambilla, Giovanni; Ciaburro, Giuseppe

2016-09-21

High flows of road traffic noise in urban agglomerations can negatively affect the livability of squares and parks located at the neighborhood, district and city levels, therefore pushing anyone who wants to enjoy calmer, quieter areas to move to non-urban parks. Due to the distances between these areas, it is not possible to go as regularly as would be necessary to satisfy any needs. Even if cities are densely populated, the presence of a sea or riverfront offers the possibility of large restorative places, or at least with potential features for being the natural core of an urban nucleus after a renewal intervention. This study evaluates the soundscape of the Naples waterfront, presenting an overview of the most significant visual, acoustic and spatial factors related to the pedestrian areas, as well as areas open to road traffic and others where the road traffic is limited. The factors were chosen with feature selection methods and artificial neural networks. The results show how certain factors, such as the perimeter between the water and promenade, the visibility of the sea or the density of green areas, can affect the perception of the soundscape quality in the areas with road traffic. In the pedestrian areas, acoustic factors, such as loudness or the A-weighted sound level exceeded for 10% of the measurement duration (LA10), influence the perceived quality of the soundscape.

Acoustic, Visual and Spatial Indicators for the Description of the Soundscape of Waterfront Areas with and without Road Traffic Flow

PubMed Central

Puyana Romero, Virginia; Maffei, Luigi; Brambilla, Giovanni; Ciaburro, Giuseppe

2016-01-01

High flows of road traffic noise in urban agglomerations can negatively affect the livability of squares and parks located at the neighborhood, district and city levels, therefore pushing anyone who wants to enjoy calmer, quieter areas to move to non-urban parks. Due to the distances between these areas, it is not possible to go as regularly as would be necessary to satisfy any needs. Even if cities are densely populated, the presence of a sea or riverfront offers the possibility of large restorative places, or at least with potential features for being the natural core of an urban nucleus after a renewal intervention. This study evaluates the soundscape of the Naples waterfront, presenting an overview of the most significant visual, acoustic and spatial factors related to the pedestrian areas, as well as areas open to road traffic and others where the road traffic is limited. The factors were chosen with feature selection methods and artificial neural networks. The results show how certain factors, such as the perimeter between the water and promenade, the visibility of the sea or the density of green areas, can affect the perception of the soundscape quality in the areas with road traffic. In the pedestrian areas, acoustic factors, such as loudness or the A-weighted sound level exceeded for 10% of the measurement duration (LA10), influence the perceived quality of the soundscape. PMID:27657105

[Research on spatial differentiation of urban stormwater runoff quality by source area monitoring].

PubMed

Li, Li-Qing; Zhu, Ren-Xiao; Guo, Shu-Gang; Yin, Cheng-Qing

2010-12-01

Runoff samples were collected from 14 source areas in Hanyang district during four rain events in an attempt to investigate the spatial differentiation and influencing factors of urban stormwater runoff quality. The outcomes are expected to offer practical guidance in sources control of urban runoff pollution. The results revealed that particle-bound proportion of chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) in stormwater runoff were 58% +/- 17%, 65% +/- 13% and 92% +/- 6%, respectively. The fractions of ammonia, nitrate and dissolved organic nitrogen were homogeneous in dissolved nitrogen composition. Urban surface function, traffic volume, land use, population density, and street sweeping practice are the main factors determining spatial differentiation of urban surface runoff quality. The highest magnitude of urban stormwater runoff pollution was expected in the old urban residential area, followed by general residential with restaurants, commercial and transport area, new developments and green land. In addition, the magnitude of road stormwater runoff pollution is positively correlated to traffic volume, in the following order: the first trunk road > the second trunk road > minor road. Street sweeping and critical source areas controls should be implemented to mitigate the adverse effects of urban stormwater runoff on receive waters.

Field test of monitoring of urban vehicle operations using non-intrusive technologies : final report

DOT National Transportation Integrated Search

2000-01-01

This document describes institutional issues associated with the retiming of traffic signals along the Scottsdale/Rural Road Corridor in Scottsdale and Tempe, Arizona in order to provide for coordinated traffic signal control in both jurisdictions. A...

Montana Bicyclist Training Program.

ERIC Educational Resources Information Center

DiBrito, Roger, Ed.; And Others

This guide is designed to train elementary students in the riding skills, hazard identification, and traffic analysis necessary for safe bicycling under nearly all urban traffic and roadway conditions. The training manual is divided into four sections. The Instructor's Manual presents brief introductions, background information, and detailed…

Road safety perspectives among employees of a multinational corporation in urban India: local context for global injury prevention.

PubMed

Jacoby, Sara F; Winston, Flaura K; Richmond, Therese S

2017-12-01

In rapidly developing economies, like urban India, where road traffic injury rates are among the world's highest, the corporate workplace offers a non-traditional venue for road safety interventions. In partnership with a major multinational corporation (MNC) with a large Indian workforce, this study aimed to elicit local employee perspectives on road safety to inform a global corporate health platform. The safety attitudes and behaviours of 75 employees were collected through self-report survey and focus groups in the MNC offices in Bangalore and Pune. Analysis of these data uncovered incongruity between employee knowledge of safety strategies and their enacted safety behaviours and identified local preference for interventions and policy-level actions. The methods modelled by this study offer a straightforward approach for eliciting employee perspective for local road safety interventions that fit within a global strategy to improve employee health. Study findings suggest that MNCs can employ a range of strategies to improve the road traffic safety of their employees in settings like urban India including: implementing corporate traffic safety policy, making local infrastructure changes to improve road and traffic conditions, advocating for road safety with government partners and providing employees with education and access to safety equipment and safe transportation options.

Achieving Passive Localization with Traffic Light Schedules in Urban Road Sensor Networks

PubMed Central

Niu, Qiang; Yang, Xu; Gao, Shouwan; Chen, Pengpeng; Chan, Shibing

2016-01-01

Localization is crucial for the monitoring applications of cities, such as road monitoring, environment surveillance, vehicle tracking, etc. In urban road sensor networks, sensors are often sparely deployed due to the hardware cost. Under this sparse deployment, sensors cannot communicate with each other via ranging hardware or one-hop connectivity, rendering the existing localization solutions ineffective. To address this issue, this paper proposes a novel Traffic Lights Schedule-based localization algorithm (TLS), which is built on the fact that vehicles move through the intersection with a known traffic light schedule. We can first obtain the law by binary vehicle detection time stamps and describe the law as a matrix, called a detection matrix. At the same time, we can also use the known traffic light information to construct the matrices, which can be formed as a collection called a known matrix collection. The detection matrix is then matched in the known matrix collection for identifying where sensors are located on urban roads. We evaluate our algorithm by extensive simulation. The results show that the localization accuracy of intersection sensors can reach more than 90%. In addition, we compare it with a state-of-the-art algorithm and prove that it has a wider operational region. PMID:27735871

Evaluating strategies to reduce urban air pollution

NASA Astrophysics Data System (ADS)

Duque, L.; Relvas, H.; Silveira, C.; Ferreira, J.; Monteiro, A.; Gama, C.; Rafael, S.; Freitas, S.; Borrego, C.; Miranda, A. I.

2016-02-01

During the last years, specific air quality problems have been detected in the urban area of Porto (Portugal). Both PM10 and NO2 limit values have been surpassed in several air quality monitoring stations and, following the European legislation requirements, Air Quality Plans were designed and implemented to reduce those levels. In this sense, measures to decrease PM10 and NO2 emissions have been selected, these mainly related to the traffic sector, but also regarding the industrial and residential combustion sectors. The main objective of this study is to investigate the efficiency of these reduction measures with regard to the improvement of PM10 and NO2 concentration levels over the Porto urban region using a numerical modelling tool - The Air Pollution Model (TAPM). TAPM was applied over the study region, for a simulation domain of 80 × 80 km2 with a spatial resolution of 1 × 1 km2. The entire year of 2012 was simulated and set as the base year for the analysis of the impacts of the selected measures. Taking into account the main activity sectors, four main scenarios have been defined and simulated, with focus on: (1) hybrid cars; (2) a Low Emission Zone (LEZ); (3) fireplaces and (4) industry. The modelling results indicate that measures to reduce PM10 should be focused on residential combustion (fireplaces) and industrial activity and for NO2 the strategy should be based on the traffic sector. The implementation of all the defined scenarios will allow a total maximum reduction of 4.5% on the levels of both pollutants.

Emission of polycyclic aromatic hydrocarbons and their carcinogenic potencies from cooking sources to the urban atmosphere.

PubMed Central

Li, Chun-The; Lin, Yuan-Chung; Lee, Wen-Jhy; Tsai, Perng-Jy

2003-01-01

Traffic has long been recognized as the major contributor to polycyclic aromatic hydrocarbon (PAH) concentrations. However, this does not consider the contribution of cooking sources of PAHs. This study set out, first, to assess the characteristics of PAHs and their corresponding benzo[a]pyrene equivalent (B[a]Peq) emissions from cooking sources to the urban atmosphere. To illustrate the importance of cooking sources, PAH emissions from traffic sources were then calculated and compared. The entire study was conducted on a city located in southern Taiwan. PAH samples were collected from the exhaust stacks of four types of restaurant: Chinese, Western, fast food, and Japanese. For total PAHs, results show that the fractions of gaseous PAHs (range, 75.9-89.9%) were consistently higher than the fractions of particulate PAHs (range, 10.1-24.1%) in emissions from the four types of restaurant. But for total B[a]Peq, we found that the contributions of gaseous PAHs (range, 15.7-21.9%) were consistently lower than the contributions of particulate PAHs (range, 78.1-84.3%). For emission rates of both total PAHs and total B[a]Peq, a consistent trend was found for the four types of restaurant: Chinese (2,038 and 154 kg/year, respectively) > Western (258 and 20.4 kg/year, respectively) > fast food (31.4 and 0.104 kg/year, respectively) > Japanese (5.11 and 0.014 kg/year, respectively). By directly adapting the emission data obtained from Chinese restaurants, we found that emission rates on total PAHs and total B[a]Peq for home kitchen sources were 6,639 and 501 kg/year, respectively. By combining both restaurant sources and home kitchen sources, this study yielded emission rates of total PAHs and total B[a]Peq from cooking sources of the studied city of 8,973 and 675 kg/year, respectively. Compared with PAH emissions from traffic sources in the same city, we found that although the emission rates of total PAHs for cooking sources were significantly less than those for traffic sources (13,500 kg/year), the emission rates of total B[a]Peq for cooking sources were much higher than those for traffic sources (61.4 kg/year). The above results clearly indicate that although cooking sources are less important than traffic sources in contributing to total PAH emissions, PAH emissions from cooking sources might cause much more serious problems than traffic sources, from the perspective of carcinogenic potency. PMID:12676603

Impacts of traffic and rainfall characteristics on heavy metals build-up and wash-off from urban roads.

PubMed

Mahbub, Parvez; Ayoko, Godwin A; Goonetilleke, Ashantha; Egodawatta, Prasanna; Kokot, Serge

2010-12-01

An investigation into the effects of changes in urban traffic characteristics due to rapid urbanisation and the predicted changes in rainfall characteristics due to climate change on the build-up and wash-off of heavy metals was carried out in Gold Coast, Australia. The study sites encompassed three different urban land uses. Nine heavy metals commonly associated with traffic emissions were selected. The results were interpreted using multivariate data analysis and decision making tools, such as principal component analysis (PCA), fuzzy clustering (FC), PROMETHEE, and GAIA. Initial analyses established high, low, and moderate traffic scenarios as well as low, low to moderate, moderate, high, and extreme rainfall scenarios for build-up and wash-off investigations. GAIA analyses established that moderate to high traffic scenarios could affect the build-up, while moderate to high rainfall scenarios could affect the wash-off of heavy metals under changed conditions. However, in wash-off, metal concentrations in 1-75 μm fraction were found to be independent of the changes to rainfall characteristics. In build-up, high traffic activities in commercial and industrial areas influenced the accumulation of heavy metal concentrations in particulate size range from 75 - >300 μm, whereas metal concentrations in finer size range of <1-75 μm were not affected. As practical implications, solids <1 μm and organic matter from 1 - >300 μm can be targeted for removal of Ni, Cu, Pb, Cd, Cr, and Zn from build-up, while organic matter from <1 - >300 μm can be targeted for removal of Cd, Cr, Pb, and Ni from wash-off. Cu and Zn need to be removed as free ions from most fractions in wash-off.

Modeling and Density Estimation of an Urban Freeway Network Based on Dynamic Graph Hybrid Automata

PubMed Central

Chen, Yangzhou; Guo, Yuqi; Wang, Ying

2017-01-01

In this paper, in order to describe complex network systems, we firstly propose a general modeling framework by combining a dynamic graph with hybrid automata and thus name it Dynamic Graph Hybrid Automata (DGHA). Then we apply this framework to model traffic flow over an urban freeway network by embedding the Cell Transmission Model (CTM) into the DGHA. With a modeling procedure, we adopt a dual digraph of road network structure to describe the road topology, use linear hybrid automata to describe multi-modes of dynamic densities in road segments and transform the nonlinear expressions of the transmitted traffic flow between two road segments into piecewise linear functions in terms of multi-mode switchings. This modeling procedure is modularized and rule-based, and thus is easily-extensible with the help of a combination algorithm for the dynamics of traffic flow. It can describe the dynamics of traffic flow over an urban freeway network with arbitrary topology structures and sizes. Next we analyze mode types and number in the model of the whole freeway network, and deduce a Piecewise Affine Linear System (PWALS) model. Furthermore, based on the PWALS model, a multi-mode switched state observer is designed to estimate the traffic densities of the freeway network, where a set of observer gain matrices are computed by using the Lyapunov function approach. As an example, we utilize the PWALS model and the corresponding switched state observer to traffic flow over Beijing third ring road. In order to clearly interpret the principle of the proposed method and avoid computational complexity, we adopt a simplified version of Beijing third ring road. Practical application for a large-scale road network will be implemented by decentralized modeling approach and distributed observer designing in the future research. PMID:28353664

Modeling and Density Estimation of an Urban Freeway Network Based on Dynamic Graph Hybrid Automata.

PubMed

Chen, Yangzhou; Guo, Yuqi; Wang, Ying

2017-03-29

In this paper, in order to describe complex network systems, we firstly propose a general modeling framework by combining a dynamic graph with hybrid automata and thus name it Dynamic Graph Hybrid Automata (DGHA). Then we apply this framework to model traffic flow over an urban freeway network by embedding the Cell Transmission Model (CTM) into the DGHA. With a modeling procedure, we adopt a dual digraph of road network structure to describe the road topology, use linear hybrid automata to describe multi-modes of dynamic densities in road segments and transform the nonlinear expressions of the transmitted traffic flow between two road segments into piecewise linear functions in terms of multi-mode switchings. This modeling procedure is modularized and rule-based, and thus is easily-extensible with the help of a combination algorithm for the dynamics of traffic flow. It can describe the dynamics of traffic flow over an urban freeway network with arbitrary topology structures and sizes. Next we analyze mode types and number in the model of the whole freeway network, and deduce a Piecewise Affine Linear System (PWALS) model. Furthermore, based on the PWALS model, a multi-mode switched state observer is designed to estimate the traffic densities of the freeway network, where a set of observer gain matrices are computed by using the Lyapunov function approach. As an example, we utilize the PWALS model and the corresponding switched state observer to traffic flow over Beijing third ring road. In order to clearly interpret the principle of the proposed method and avoid computational complexity, we adopt a simplified version of Beijing third ring road. Practical application for a large-scale road network will be implemented by decentralized modeling approach and distributed observer designing in the future research.

A Modeling Investigation of Human Exposure to Select Traffic-Related Air Pollutants in the Tampa Area: Spatiotemporal Distributions of Concentrations, Social Distributions of Exposures, and Impacts of Urban Design on Both

NASA Astrophysics Data System (ADS)

Yu, Haofei

Increasing vehicle dependence in the United States has resulted in substantial emissions of traffic-related air pollutants that contribute to the deterioration of urban air quality. Exposure to urban air pollutants trigger a number of public health concerns, including the potential of inequality of exposures and health effects among population subgroups. To better understand the impact of traffic-related pollutants on air quality, exposure, and exposure inequality, modeling methods that can appropriately characterize the spatiotemporally resolved concentration distributions of traffic-related pollutants need to be improved. These modeling methods can then be used to investigate the impacts of urban design and transportation management choices on air quality, pollution exposures, and related inequality. This work will address these needs with three objectives: 1) to improve modeling methods for investigating interactions between city and transportation design choices and air pollution exposures, 2) to characterize current exposures and the social distribution of exposures to traffic-related air pollutants for the case study area of Hillsborough County, Florida, and 3) to determine expected impacts of urban design and transportation management choices on air quality, air pollution exposures, and exposure inequality. To achieve these objectives, the impacts of a small-scale transportation management project, specifically the '95 Express' high occupancy toll lane project, on pollutant emissions and nearby air quality was investigated. Next, a modeling method capable of characterizing spatiotemporally resolved pollutant emissions, concentrations, and exposures was developed and applied to estimate the impact of traffic-related pollutants on exposure and exposure inequalities among several population subgroups in Hillsborough County, Florida. Finally, using these results as baseline, the impacts of sprawl and compact urban forms, as well as vehicle fleet electrification, on air quality, pollution exposure, and exposure inequality were explored. Major findings include slightly higher pollutant emissions, with the exception of hydrocarbons, due to the managed lane project. Results also show that ambient concentration contributions from on-road mobile sources are disproportionate to their emissions. Additionally, processes not captured by the CALPUFF model, such as atmospheric formation, contribute substantially to ambient concentration levels of the secondary pollutants such as acetaldehyde and formaldehyde. Exposure inequalities for NOx, 1,3-butadiene, and benzene air pollution were found for black, Hispanic, and low income (annual household income less than $20,000) subgroups at both short-term and long-term temporal scales, which is consistent with previous findings. Exposure disparities among the subgroups are complex, and sometimes reversed for acetaldehyde and formaldehyde, due primarily to their distinct concentration distributions. Compact urban form was found to result in lower average NOx and benzene concentrations, but higher exposure for all pollutants except for NOx when compared to sprawl urban form. Evidence suggests that exposure inequalities differ between sprawl and compact urban forms, and also differ by pollutants, but are generally consistent at both short and long-term temporal scales. In addition, vehicle fleet electrification was found to result in generally lower average pollutant concentrations and exposures, except for NOx. However, the elimination of on-road mobile source emissions does not substantially reduce exposure inequality. Results and findings from this work can be applied to assist transportation infrastructure and urban planning. In addition, method developed here can be applied elsewhere for better characterization of air pollution concentrations, exposure and related inequalities.

Multi-resolution model-based traffic sign detection and tracking

NASA Astrophysics Data System (ADS)

Marinas, Javier; Salgado, Luis; Camplani, Massimo

2012-06-01

In this paper we propose an innovative approach to tackle the problem of traffic sign detection using a computer vision algorithm and taking into account real-time operation constraints, trying to establish intelligent strategies to simplify as much as possible the algorithm complexity and to speed up the process. Firstly, a set of candidates is generated according to a color segmentation stage, followed by a region analysis strategy, where spatial characteristic of previously detected objects are taken into account. Finally, temporal coherence is introduced by means of a tracking scheme, performed using a Kalman filter for each potential candidate. Taking into consideration time constraints, efficiency is achieved two-fold: on the one side, a multi-resolution strategy is adopted for segmentation, where global operation will be applied only to low-resolution images, increasing the resolution to the maximum only when a potential road sign is being tracked. On the other side, we take advantage of the expected spacing between traffic signs. Namely, the tracking of objects of interest allows to generate inhibition areas, which are those ones where no new traffic signs are expected to appear due to the existence of a TS in the neighborhood. The proposed solution has been tested with real sequences in both urban areas and highways, and proved to achieve higher computational efficiency, especially as a result of the multi-resolution approach.

Factors associated with civilian drivers involved in crashes with emergency vehicles.

PubMed

Drucker, Christopher; Gerberich, Susan G; Manser, Michael P; Alexander, Bruce H; Church, Timothy R; Ryan, Andrew D; Becic, Ensar

2013-06-01

Motor vehicle crashes involving civilian and emergency vehicles (EVs) have been a known problem that contributes to fatal and nonfatal injuries; however, characteristics associated with civilian drivers have not been examined adequately. This study used data from The National Highway Traffic Safety Administration's Fatality Analysis Reporting System and the National Automotive Sampling System General Estimates System to identify driver, roadway, environmental, and crash factors, and consequences for civilian drivers involved in fatal and nonfatal crashes with in-use and in-transport EVs. In general, drivers involved in emergency-civilian crashes (ECCs) were more often driving: straight through intersections (vs. same direction) of four-points or more (vs. not at intersection); where traffic signals were present (vs. no traffic control device); and at night (vs. midday). For nonfatal ECCs, drivers were more often driving: distracted (vs. not distracted); with vision obstructed by external objects (vs. no obstruction); on dark but lighted roads (vs. daylight); and in opposite directions (vs. same directions) of the EVs. Consequences included increased risk of injury (vs. no injury) and receiving traffic violations (vs. no violation). Fatal ECCs were associated with driving on urban roads (vs. rural), although these types of crashes were less likely to occur on dark roads (vs. daylight). The findings of this study suggest drivers may have difficulties in visually detecting EVs in different environments. Copyright © 2013 Elsevier Ltd. All rights reserved.

Link state relationships under incident conditions : using a CTM-based linear programming dynamic traffic assignment model.

DOT National Transportation Integrated Search

2010-03-01

Urban transportation networks, consisting of numerous links and nodes, experience traffic incidents such as accidents and road : maintenance work. A typical consequence of incidents is congestion which results in long queues and causes high travel ti...

Link State Relationships Under Incident Conditions: Using a CTM-Based Linear Programming Dynamic Traffic Assignment Model

DOT National Transportation Integrated Search

2010-03-01

Urban transportation networks, consisting of numerous links and nodes, experience traffic incidents such as accidents and road maintenance work. A typical consequence of incidents is congestion which results in long queues and causes high travel time...

Transportation Energy Futures (TEF) Data and Sources

Science.gov Websites

|agency|4-d|gis|geographic information systems?|municipal|neighborhood|urban density|municipal |carsharing|marketing|real-time|traffic information|eco-driving|idle)$ ^(vmt|vehicle miles traveled|reduction drive|eco-driving|congestion|commute|telework|alternative work|parking|real-time|traffic information

Enhancing non-motorized safety by simulating non-motorized exposure using a transportation planning approach : final report.

DOT National Transportation Integrated Search

2016-06-01

Safety researchers and analysists have employed land use and urban form variables as surrogates for traffic exposure information (pedestrian and bicyclist volumes and vehicular traffic). The quality of these crash prediction models is affected by the...

Analysis of traffic accident data in Kentucky (1995-1999)

DOT National Transportation Integrated Search

2000-09-01

This report includes an analysis of traffic accidents data in Kentucky for the year 1995-1999. A primary objective of this study was to determined average and critical numbers and rates of accidents for various types of highways in rural and urban ar...

Optimal signal timing design for urban street networks under user equilibrium based traffic conditions : final report.

DOT National Transportation Integrated Search

2016-09-20

In the ever-growing travel demand, traffic congestion on freeways and expressways : recurs more frequently at a higher number of locations and for longer durations with : added severity. This becomes especially true in large metropolitan areas. Parti...

Assessing segment- and corridor-based travel-time reliability on urban freeways tech transfer summary : tech transfer summary.

DOT National Transportation Integrated Search

2016-09-01

Travel time and travel-time reliability have been used as performance : measures to evaluate traffic system conditions and develop advanced : traveler information and traffic management systems. The objectives of this research were to: : - Quantify s...

Characterization of arterial traffic congestion through analysis of operational parameters (gap acceptance and lane changing).

DOT National Transportation Integrated Search

2010-05-01

This project monitored an urban arterial highway to characterize recurring congestion. There were two major initiatives in the project. The first one focused on observed variations in gap acceptance and lane changing in relation to traffic flow rates...

Can weekly noise levels of urban road traffic, as predominant noise source, estimate annual ones?

PubMed

Prieto Gajardo, Carlos; Barrigón Morillas, Juan Miguel; Rey Gozalo, Guillermo; Vílchez-Gómez, Rosendo

2016-11-01

The effects of noise pollution on human quality of life and health were recognised by the World Health Organisation a long time ago. There is a crucial dilemma for the study of urban noise when one is looking for proven methodologies that can allow, on the one hand, an increase in the quality of predictions, and on the other hand, saving resources in the spatial and temporal sampling. The temporal structure of urban noise is studied in this work from a different point of view. This methodology, based on Fourier analysis, is applied to several measurements of urban noise, mainly from road traffic and one-week long, carried out in two cities located on different continents and with different sociological life styles (Cáceres, Spain and Talca, Chile). Its capacity to predict annual noise levels from weekly measurements is studied. The relation between this methodology and the categorisation method is also analysed.

Construction of road network vulnerability evaluation index based on general travel cost

NASA Astrophysics Data System (ADS)

Leng, Jun-qiang; Zhai, Jing; Li, Qian-wen; Zhao, Lin

2018-03-01

With the development of China's economy and the continuous improvement of her urban road network, the vulnerability of the urban road network has attracted increasing attention. Based on general travel cost, this work constructs the vulnerability evaluation index for the urban road network, and evaluates the vulnerability of the urban road network from the perspective of user generalised travel cost. Firstly, the generalised travel cost model is constructed based on vehicle cost, travel time, and traveller comfort. Then, the network efficiency index is selected as an evaluation index of vulnerability: the network efficiency index is composed of the traffic volume and the generalised travel cost, which are obtained from the equilibrium state of the network. In addition, the research analyses the influence of traffic capacity decrease, road section attribute value, and location of road section, on vulnerability. Finally, the vulnerability index is used to analyse the local area network of Harbin and verify its applicability.

Benzene patterns in different urban environments and a prediction model for benzene rates based on NOx values

NASA Astrophysics Data System (ADS)

Paz, Shlomit; Goldstein, Pavel; Kordova-Biezuner, Levana; Adler, Lea

2017-04-01

Exposure to benzene has been associated with multiple severe impacts on health. This notwithstanding, at most monitoring stations, benzene is not monitored on a regular basis. The aims of the study were to compare benzene rates in different urban environments (region with heavy traffic and industrial region), to analyse the relationship between benzene and meteorological parameters in a Mediterranean climate type, to estimate the linkages between benzene and NOx and to suggest a prediction model for benzene rates based on NOx levels in order contribute to a better estimation of benzene. Data were used from two different monitoring stations, located on the eastern Mediterranean coast: 1) a traffic monitoring station in Tel Aviv, Israel (TLV) located in an urban region with heavy traffic; 2) a general air quality monitoring station in Haifa Bay (HIB), located in Israel's main industrial region. At each station, hourly, daily, monthly, seasonal, and annual data of benzene, NOx, mean temperature, relative humidity, inversion level, and temperature gradient were analysed over three years: 2008, 2009, and 2010. A prediction model for benzene rates based on NOx levels (which are monitored regularly) was developed to contribute to a better estimation of benzene. The severity of benzene pollution was found to be considerably higher at the traffic monitoring station (TLV) than at the general air quality station (HIB), despite the location of the latter in an industrial area. Hourly, daily, monthly, seasonal, and annual patterns have been shown to coincide with anthropogenic activities (traffic), the day of the week, and atmospheric conditions. A strong correlation between NOx and benzene allowed the development of a prediction model for benzene rates, based on NOx, the day of the week, and the month. The model succeeded in predicting the benzene values throughout the year (except for September). The severity of benzene pollution was found to be considerably higher at the traffic station (TLV) than at the general air quality station (HIB), despite being located in an industrial area. Hourly, daily, seasonal, and annual patterns of benzene rates have been shown to coincide with anthropogenic activities (traffic), day of the week, and atmospheric conditions. A prediction model for benzene rates was developed, based on NOx, the day of the week, and the month. The model suggested in this study might be useful for identifying potential risk of benzene in other urban environments.

Assessment of the impacts of vehicular pollution on urban air quality.

PubMed

Ghose, Mrinal K; Paul, R; Banerjee, S K

2004-01-01

Air quality crisis in cities is mainly due to vehicular emissions. Owing to the expanding economic base Indian cities are growing at a faster rate. Transportation systems are increasing everywhere and the improved technology is insufficient to counteract growth. The effect of vehicular emission on urban air quality and human health has been described. A survey has been conducted in an Indian mega city to evaluate the status of air pollution at traffic intersections and the unique problem arising out of vehicular emissions in the study area has been narrated. Approach for the selection of the air monitoring stations, methodology adopted for data collection and the results have been discussed. Vulnerability analysis (VA) has been carried out to identify the zones at what pollution stress. Options for reducing mobile source emission have been discussed and a strategic air quality management plan has been proposed to mitigate the air pollution in the city.

Air Quality Modeling in Support of the Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS)

EPA Science Inventory

A major challenge in traffic-related air pollution exposure studies is the lack of information regarding pollutant exposure characterization. Air quality modeling can provide spatially and temporally varying exposure estimates for examining relationships between traffic-related a...

Powered two-wheeler riders' risk of crashes associated with filtering on urban roads.

PubMed

Clabaux, Nicolas; Fournier, Jean-Yves; Michel, Jean-Emmanuel

2017-02-17

The objective of this study is to estimate the crash risk per kilometer traveled by powered two-wheeler (PTW) riders filtering through traffic on urban roads. Using the traffic injury crashes recorded by the police over a period of 3 years on 14 sections of urban roads in the city of Marseille, France, and a campaign of observations of PTWs, the crash risk per kilometer traveled by PTWs filtering was estimated and compared to the risk of PTWs that did not filter. The results show that the risk of PTW riders being involved in injury crashes while filtering is significantly higher than the risk for riders who do not filter. For the 14 sections studied, it is 3.94 times greater (95% confidence interval [CI], 2.63, 5.89). This excess risk occurred for all PTW categories. Furthermore, no space appears to be safer than the others for filtering. Riders filtering forward along the axis of the carriageway, along bus lanes, or between traffic lanes (lane-splitting) all have a crash risk greater than the risk of those who do not filter. All measures limiting the practice of filtering by PTWs on urban roads would probably contribute to improving the safety of their users.

Chemical composition and mass closure of ambient coarse particles at traffic and urban-background sites in Thessaloniki, Greece.

PubMed

Grigoratos, Theodoros; Samara, Constantini; Voutsa, Dimitra; Manoli, Evangelia; Kouras, Athanasios

2014-06-01

Concentrations and chemical composition of the coarse particle fraction (PMc) were investigated at two urban sites in the city of Thessaloniki, Greece, through concurrent sampling of PM10 and PM2.5 during the warm and the cold months of the year. PMc levels at the urban-traffic site (UT) were among the highest found in literature worldwide exhibiting higher values in the cold period. PMc levels at the urban-background site (UB) were significantly lower exhibiting a reverse seasonal trend. Concentration levels of minerals and most trace metals were also higher at the UT site suggesting a stronger impact from traffic-related sources (road dust resuspension, brake and tire abrasion, road wear). According to the chemical mass closure obtained, minerals (oxides of Si, Al, Ca, Mg, Fe, Ti, and K) dominated the PMc profile, regardless of the site and the period, with organic matter and secondary inorganic aerosols (mainly nitrate) also contributing considerably to the PMc mass, particularly in the warm period. The influence of wind speed to dilution and/or resuspension of coarse particles was investigated. The source of origin of coarse particles was also investigated using surface wind data and atmospheric back-trajectory modeling. Finally, the contribution of resuspension to PMc levels was estimated for air quality management perspectives.

Grain size distribution of road-deposited sediment and its contribution to heavy metal pollution in urban runoff in Beijing, China.

PubMed

Zhao, Hongtao; Li, Xuyong; Wang, Xiaomei; Tian, Di

2010-11-15

Pollutant washoff from road-deposited sediment (RDS) is an increasing problem associated with the rapid urbanization of China that results in urban non-point source pollution. Here, we analyzed the RDS grain size distribution and its potential impact on heavy metal pollution in urban runoff from impervious surfaces of urban villages, colleges and residences, and main traffic roads in the Haidian District, Beijing, China. RDS with smaller grain size had a higher metal concentration. Specifically, particles with the smallest grain size (<44 μm) had the highest metal concentration in most areas (unit: mg/kg): Cd 0.28-1.31, Cr 57.9-154, Cu 68.1-142, Ni 25.8-78.0, Pb 73.1-222 and Zn 264-664. Particles with smaller grain size (<250 μm) contributed more than 80% of the total metal loads in RDS washoff, while suspended solids with a grain size <44 μm in runoff water accounted for greater than 70% of the metal mass in the total suspended solids (TSS). The heavy metal content in the TSS was 2.21-6.52% of that in the RDS. These findings will facilitate our understanding of the importance of RDS grain size distribution in heavy metal pollution caused by urban storm runoff. Copyright © 2010 Elsevier B.V. All rights reserved.

Urban scale air quality modelling using detailed traffic emissions estimates

NASA Astrophysics Data System (ADS)

Borrego, C.; Amorim, J. H.; Tchepel, O.; Dias, D.; Rafael, S.; Sá, E.; Pimentel, C.; Fontes, T.; Fernandes, P.; Pereira, S. R.; Bandeira, J. M.; Coelho, M. C.

2016-04-01

The atmospheric dispersion of NOx and PM10 was simulated with a second generation Gaussian model over a medium-size south-European city. Microscopic traffic models calibrated with GPS data were used to derive typical driving cycles for each road link, while instantaneous emissions were estimated applying a combined Vehicle Specific Power/Co-operative Programme for Monitoring and Evaluation of the Long-range Transmission of Air Pollutants in Europe (VSP/EMEP) methodology. Site-specific background concentrations were estimated using time series analysis and a low-pass filter applied to local observations. Air quality modelling results are compared against measurements at two locations for a 1 week period. 78% of the results are within a factor of two of the observations for 1-h average concentrations, increasing to 94% for daily averages. Correlation significantly improves when background is added, with an average of 0.89 for the 24 h record. The results highlight the potential of detailed traffic and instantaneous exhaust emissions estimates, together with filtered urban background, to provide accurate input data to Gaussian models applied at the urban scale.

Evaluating the Safety In Numbers effect for pedestrians at urban intersections.

PubMed

Murphy, Brendan; Levinson, David M; Owen, Andrew

2017-09-01

Assessment of collision risk between pedestrians and automobiles offers a powerful and informative tool in urban planning applications, and can be leveraged to inform proper placement of improvements and treatment projects to improve pedestrian safety. Such assessment can be performed using existing datasets of crashes, pedestrian counts, and automobile traffic flows to identify intersections or corridors characterized by elevated collision risks to pedestrians. The Safety In Numbers phenomenon, which refers to the observable effect that pedestrian safety is positively correlated with increased pedestrian traffic in a given area (i.e. that the individual per-pedestrian risk of a collision decreases with additional pedestrians), is a readily observed phenomenon that has been studied previously, though its directional causality is not yet known. A sample of 488 intersections in Minneapolis were analyzed, and statistically-significant log-linear relationships between pedestrian traffic flows and the per-pedestrian crash risk were found, indicating the Safety In Numbers effect. Potential planning applications of this analysis framework towards improving pedestrian safety in urban environments are discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Safety assessment on pedestrian crossing environments using MLS data.

PubMed

Soilán, Mario; Riveiro, Belén; Sánchez-Rodríguez, Ana; Arias, Pedro

2018-02-01

In the framework of infrastructure analysis and maintenance in an urban environment, it is important to address the safety of every road user. This paper presents a methodology for the evaluation of several safety indicators on pedestrian crossing environments using geometric and radiometric information extracted from 3D point clouds collected by a Mobile Mapping System (MMS). The methodology is divided in four main modules which analyze the accessibility of the crossing area, the presence of traffic lights and traffic signs, and the visibility between a driver and a pedestrian on the proximities of a pedestrian crossing. The outputs of the analysis are exported to a Geographic Information System (GIS) where they are visualized and can be further processed in the context of city management. The methodology has been tested on approximately 30 pedestrian crossings in cluttered urban environments of two different cities. Results show that MMS are a valid mean to assess the safety of a specific urban environment, regarding its geometric conditions. Remarkable results are presented on traffic light classification, with a global F-score close to 95%. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Modeling the vehicle pollution in the urban streets before and during the Beijing Olympic Games traffic control period].

PubMed

Wang, Ting; Xie, Shao-dong

2010-03-01

In order to investigate the vehicle pollution situation in the streets in Beijing and the abatement during the Olympic Games, the OSPM model was applied to calculate the concentrations of PM10, CO, NO2 and O3 inside the urban streets of Beijing before and during the Olympic traffic controlling period in July, 2008. The modeled concentrations before the traffic control are 146 micog/m3, 3.83 mg/m3, 114.4 microg/m3 and 4.71 x 10(-1), while after the traffic control are 112 microg/m3, 3.16 mg/m3, 102.4 microg/m3 and 5.31 x 10(-9) , with the reduction rates of 23.4%, 20.5%, 10.5% and -12.5%, respectively. The research on these concentration changes and the daily variations of the pollutants reveals: the concentration of PM10 is most influenced by the traffic control; the concentration of CO presents the most similar daily variation with the traffic flow; the reduction of NO2 concentration is limited, indicating the influence of other factors other than the traffic emission; the concentration of O3 increases after the traffic control, which means the traffic management measures can not abate the O3 pollution in the street. Furthermore, the comparison between the calculation results in different types of street canyons reveals that the fleet composition and street geometry impact the concentration changes. In a word, the vehicle pollution inside the streets of Beijing before the traffic control is relatively serious, as the concentrations of PM10, CO and NO2, all approach or exceed the Grade II National Air Quality Standard; the traffic control measures take effect in reducing the primary pollutants, but the secondary pollutants may increase after the traffic control.

Research notes : roadway design treatments for rural to urban transitions.

DOT National Transportation Integrated Search

2008-12-01

An ODOT Research study, lead by Karen Dixon at Oregon State University, reviewed research evaluating potential traffic calming strategies for rural-to-urban transitions on high speed highways. Driving simulator evaluations were conducted to assess se...

Air quality assessment at a congested urban intersection

DOT National Transportation Integrated Search

2000-09-01

The deficient transportation system of Beirut results in significant economic losses for the city and causes severe traffic congestion in the urban areas. Proposals have been made for grade separations at some of the worst congested intersections. Th...

Evaluation of Urban Freight Deliveries using Microsimulation and Surrogate Safety Measures

DOT National Transportation Integrated Search

2018-02-01

Freight deliveries on signalized urban streets are known to cause lane blockages during deliveries. When delivery vehicles block lanes of traffic near signalized intersections, the capacity of the intersection is affected. Current practice is for tra...

Visual traffic jam analysis based on trajectory data.

PubMed

Wang, Zuchao; Lu, Min; Yuan, Xiaoru; Zhang, Junping; van de Wetering, Huub

2013-12-01

In this work, we present an interactive system for visual analysis of urban traffic congestion based on GPS trajectories. For these trajectories we develop strategies to extract and derive traffic jam information. After cleaning the trajectories, they are matched to a road network. Subsequently, traffic speed on each road segment is computed and traffic jam events are automatically detected. Spatially and temporally related events are concatenated in, so-called, traffic jam propagation graphs. These graphs form a high-level description of a traffic jam and its propagation in time and space. Our system provides multiple views for visually exploring and analyzing the traffic condition of a large city as a whole, on the level of propagation graphs, and on road segment level. Case studies with 24 days of taxi GPS trajectories collected in Beijing demonstrate the effectiveness of our system.

Urban air quality, meteorology and traffic linkages: Evidence from a sixteen-day particulate matter pollution event in December 2015, Beijing.

PubMed

Hu, Dongmei; Wu, Jianping; Tian, Kun; Liao, Lyuchao; Xu, Ming; Du, Yiman

2017-09-01

A heavy 16-day pollution episode occurred in Beijing from December 19, 2015 to January 3, 2016. The mean daily AQI and PM 2.5 were 240.44 and 203.6μg/m 3 . We analyzed the spatiotemporal characteristics of air pollutants, meteorology and road space speed during this period, then extended to reveal the combined effects of traffic restrictions and meteorology on urban air quality with observational data and a multivariate mutual information model. Results of spatiotemporal analysis showed that five pollution stages were identified with remarkable variation patterns based on evolution of PM 2.5 concentration and weather conditions. Southern sites (DX, YDM and DS) experienced heavier pollution than northern ones (DL, CP and WL). Stage P2 exhibited combined functions of meteorology and traffic restrictions which were delayed peak-clipping effects on PM 2.5 . Mutual information values of Air quality-Traffic-Meteorology (ATM-MI) revealed that additive functions of traffic restrictions, suitable relative humidity and temperature were more effective on the removal of fine particles and CO than NO 2 . Copyright © 2017. Published by Elsevier B.V.

Cloud-based large-scale air traffic flow optimization

NASA Astrophysics Data System (ADS)

Cao, Yi

The ever-increasing traffic demand makes the efficient use of airspace an imperative mission, and this paper presents an effort in response to this call. Firstly, a new aggregate model, called Link Transmission Model (LTM), is proposed, which models the nationwide traffic as a network of flight routes identified by origin-destination pairs. The traversal time of a flight route is assumed to be the mode of distribution of historical flight records, and the mode is estimated by using Kernel Density Estimation. As this simplification abstracts away physical trajectory details, the complexity of modeling is drastically decreased, resulting in efficient traffic forecasting. The predicative capability of LTM is validated against recorded traffic data. Secondly, a nationwide traffic flow optimization problem with airport and en route capacity constraints is formulated based on LTM. The optimization problem aims at alleviating traffic congestions with minimal global delays. This problem is intractable due to millions of variables. A dual decomposition method is applied to decompose the large-scale problem such that the subproblems are solvable. However, the whole problem is still computational expensive to solve since each subproblem is an smaller integer programming problem that pursues integer solutions. Solving an integer programing problem is known to be far more time-consuming than solving its linear relaxation. In addition, sequential execution on a standalone computer leads to linear runtime increase when the problem size increases. To address the computational efficiency problem, a parallel computing framework is designed which accommodates concurrent executions via multithreading programming. The multithreaded version is compared with its monolithic version to show decreased runtime. Finally, an open-source cloud computing framework, Hadoop MapReduce, is employed for better scalability and reliability. This framework is an "off-the-shelf" parallel computing model that can be used for both offline historical traffic data analysis and online traffic flow optimization. It provides an efficient and robust platform for easy deployment and implementation. A small cloud consisting of five workstations was configured and used to demonstrate the advantages of cloud computing in dealing with large-scale parallelizable traffic problems.

Assessment of discrepancies between bottom-up and regional emission inventories in Norwegian urban areas

NASA Astrophysics Data System (ADS)

López-Aparicio, Susana; Guevara, Marc; Thunis, Philippe; Cuvelier, Kees; Tarrasón, Leonor

2017-04-01

This study shows the capabilities of a benchmarking system to identify inconsistencies in emission inventories, and to evaluate the reason behind discrepancies as a mean to improve both bottom-up and downscaled emission inventories. Fine scale bottom-up emission inventories for seven urban areas in Norway are compared with three regional emission inventories, EC4MACS, TNO_MACC-II and TNO_MACC-III, downscaled to the same areas. The comparison shows discrepancies in nitrogen oxides (NOx) and particulate matter (PM2.5 and PM10) when evaluating both total and sectorial emissions. The three regional emission inventories underestimate NOx and PM10 traffic emissions by approximately 20-80% and 50-90%, respectively. The main reasons for the underestimation of PM10 emissions from traffic in the regional inventories are related to non-exhaust emissions due to resuspension, which are included in the bottom-up emission inventories but are missing in the official national emissions, and therefore in the downscaled regional inventories. The benchmarking indicates that the most probable reason behind the underestimation of NOx traffic emissions by the regional inventories is the activity data. The fine scale NOx traffic emissions from bottom-up inventories are based on the actual traffic volume at the road link and are much higher than the NOx emissions downscaled from national estimates based on fuel sales and based on population for the urban areas. We have identified important discrepancies in PM2.5 emissions from wood burning for residential heating among all the inventories. These discrepancies are associated with the assumptions made for the allocation of emissions. In the EC4MACs inventory, such assumptions imply high underestimation of PM2.5 emissions from the residential combustion sector in urban areas, which ranges from 40 to 90% compared with the bottom-up inventories. The study shows that in three of the seven Norwegian cities there is need for further improvement of the emission inventories.

Speed, speed variation and crash relationships for urban arterials.

PubMed

Wang, Xuesong; Zhou, Qingya; Quddus, Mohammed; Fan, Tianxiang; Fang, Shou'en

2018-04-01

Speed and speed variation are closely associated with traffic safety. There is, however, a dearth of research on this subject for the case of urban arterials in general, and in the context of developing nations. In downtown Shanghai, the traffic conditions in each direction are very different by time of day, and speed characteristics during peak hours are also greatly different from those during off-peak hours. Considering that traffic demand changes with time and in different directions, arterials in this study were divided into one-way segments by the direction of flow, and time of day was differentiated and controlled for. In terms of data collection, traditional fixed-based methods have been widely used in previous studies, but they fail to capture the spatio-temporal distributions of speed along a road. A new approach is introduced to estimate speed variation by integrating spatio-temporal speed fluctuation of a single vehicle with speed differences between vehicles using taxi-based high frequency GPS data. With this approach, this paper aims to comprehensively establish a relationship between mean speed, speed variation and traffic crashes for the purpose of formulating effective speed management measures, specifically using an urban dataset. From a total of 234 one-way road segments from eight arterials in Shanghai, mean speed, speed variation, geometric design features, traffic volume, and crash data were collected. Because the safety effects of mean speed and speed variation may vary at different segment lengths, arterials with similar signal spacing density were grouped together. To account for potential correlations among these segments, a hierarchical Poisson log-normal model with random effects was developed. Results show that a 1% increase in mean speed on urban arterials was associated with a 0.7% increase in total crashes, and larger speed variation was also associated with increased crash frequency. Copyright © 2018 Elsevier Ltd. All rights reserved.

A Green Soundscape Index (GSI): The potential of assessing the perceived balance between natural sound and traffic noise.

PubMed

Kogan, Pablo; Arenas, Jorge P; Bermejo, Fernando; Hinalaf, María; Turra, Bruno

2018-06-13

Urban soundscapes are dynamic and complex multivariable environmental systems. Soundscapes can be organized into three main entities containing the multiple variables: Experienced Environment (EE), Acoustic Environment (AE), and Extra-Acoustic Environment (XE). This work applies a multidimensional and synchronic data-collecting methodology at eight urban environments in the city of Córdoba, Argentina. The EE was assessed by means of surveys, the AE by acoustic measurements and audio recordings, and the XE by photos, video, and complementary sources. In total, 39 measurement locations were considered, where data corresponding to 61 AE and 203 EE were collected. Multivariate analysis and GIS techniques were used for data processing. The types of sound sources perceived, and their extents make up part of the collected variables that belong to the EE, i.e. traffic, people, natural sounds, and others. Sources explaining most of the variance were traffic noise and natural sounds. Thus, a Green Soundscape Index (GSI) is defined here as the ratio of the perceived extents of natural sounds to traffic noise. Collected data were divided into three ranges according to GSI value: 1) perceptual predominance of traffic noise, 2) balanced perception, and 3) perceptual predominance of natural sounds. For each group, three additional variables from the EE and three from the AE were applied, which reported significant differences, especially between ranges 1 and 2 with 3. These results confirm the key role of perceiving natural sounds in a town environment and also support the proposal of a GSI as a valuable indicator to classify urban soundscapes. In addition, the collected GSI-related data significantly helps to assess the overall soundscape. It is noted that this proposed simple perceptual index not only allows one to assess and classify urban soundscapes but also contributes greatly toward a technique for separating environmental sound sources. Copyright © 2018 Elsevier B.V. All rights reserved.

Social inequalities in residential exposure to road traffic noise: an environmental justice analysis based on the RECORD Cohort Study.

PubMed

Havard, Sabrina; Reich, Brian J; Bean, Kathy; Chaix, Basile

2011-05-01

To explore social inequalities in residential exposure to road traffic noise in an urban area. Environmental injustice in road traffic noise exposure was investigated in Paris, France, using the RECORD Cohort Study (n = 2130) and modelled noise data. Associations were assessed by estimating noise exposure within the local area around participants' residence, considering various socioeconomic variables defined at both individual and neighbourhood level, and comparing different regression models attempting or not to control for spatial autocorrelation in noise levels. After individual-level adjustment, participants' noise exposure increased with neighbourhood educational level and dwelling value but also with proportion of non-French citizens, suggesting seemingly contradictory findings. However, when country of citizenship was defined according to its human development level, noise exposure in fact increased and decreased with the proportions of citizens from advantaged and disadvantaged countries, respectively. These findings were consistent with those reported for the other socioeconomic characteristics, suggesting higher road traffic noise exposure in advantaged neighbourhoods. Substantial collinearity between neighbourhood explanatory variables and spatial random effects caused identifiability problems that prevented successful control for spatial autocorrelation. Contrary to previous literature, this study shows that people living in advantaged neighbourhoods were more exposed to road traffic noise in their residential environment than their deprived counterparts. This case study demonstrates the need to systematically perform sensitivity analyses with multiple socioeconomic characteristics to avoid incorrect inferences about an environmental injustice situation and the complexity of effectively controlling for spatial autocorrelation when fixed and random components of the model are correlated.

Enabling Airspace Integration for High Density Urban Air Mobility

NASA Technical Reports Server (NTRS)

Mueller, Eric Richard

2017-01-01

Aviation technologies and concepts have reached a level of maturity that may soon enable an era of on-demand mobility (ODM) fueled by quiet, efficient, and largely automated air taxis. However, successfully bringing such a system to fruition will require introducing orders of magnitude more aircraft to a given airspace volume than can be accommodated by the traditional air traffic control system, among other important technical challenges. The airspace integration problem is further compounded by requirements to set aside appropriate ground infrastructure for take-off and landing areas and ensuring these new aircraft types and their operations do not burden traditional airspace users and air traffic control. These challenge for ODM may be significantly reduced by extending the concepts and technologies developed to manage small unmanned aircraft systems (UAS) at low altitude the UAS traffic management (UTM) system to higher altitudes and aircraft with humans onboard in controlled airspace, or by equipping ODM aircraft with advanced sensors, algorithms, and interfaces. The precedent of operational freedom inherent in visual flight rules and the technologies developed for large UAS and commercial aircraft automation will contribute to the evolution of an ODM system enabled by UTM. This paper describes the set of air traffic services, normally provided by the traditional air traffic system, that an ODM system would implement to achieve the high densities needed for ODMs economic viability. Finally, the paper proposes a framework for integrating, evaluating, and deploying low-, medium-, and high-density ODM concepts that build on each other to ensure operational and economic feasibility at every step.

Dynamic analysis of pedestrian crossing behaviors on traffic flow at unsignalized mid-block crosswalks

NASA Astrophysics Data System (ADS)

Liu, Gang; He, Jing; Luo, Zhiyong; Yang, Wunian; Zhang, Xiping

2015-05-01

It is important to study the effects of pedestrian crossing behaviors on traffic flow for solving the urban traffic jam problem. Based on the Nagel-Schreckenberg (NaSch) traffic cellular automata (TCA) model, a new one-dimensional TCA model is proposed considering the uncertainty conflict behaviors between pedestrians and vehicles at unsignalized mid-block crosswalks and defining the parallel updating rules of motion states of pedestrians and vehicles. The traffic flow is simulated for different vehicle densities and behavior trigger probabilities. The fundamental diagrams show that no matter what the values of vehicle braking probability, pedestrian acceleration crossing probability, pedestrian backing probability and pedestrian generation probability, the system flow shows the "increasing-saturating-decreasing" trend with the increase of vehicle density; when the vehicle braking probability is lower, it is easy to cause an emergency brake of vehicle and result in great fluctuation of saturated flow; the saturated flow decreases slightly with the increase of the pedestrian acceleration crossing probability; when the pedestrian backing probability lies between 0.4 and 0.6, the saturated flow is unstable, which shows the hesitant behavior of pedestrians when making the decision of backing; the maximum flow is sensitive to the pedestrian generation probability and rapidly decreases with increasing the pedestrian generation probability, the maximum flow is approximately equal to zero when the probability is more than 0.5. The simulations prove that the influence of frequent crossing behavior upon vehicle flow is immense; the vehicle flow decreases and gets into serious congestion state rapidly with the increase of the pedestrian generation probability.

Transportation Energy Use and Conservation Potential

ERIC Educational Resources Information Center

Hirst, Eric

1973-01-01

Analyzes transportation energy consumption and energy intensiveness for inter-city freight and passenger traffic and urban passenger traffic with the definition of energy intensiveness as Btu per ton-mile or per passenger-mile. Indicates that public education is one of three ways to achieve the goals of energy conservation. (CC)

Heavy vehicle performance during recovery from forced-flow urban freeway conditions due to incidents, work zones and recurring congestion.

DOT National Transportation Integrated Search

2013-12-01

Information contained in the Highway Capacity Manual on the influence heavy vehicles have on freeway traffic : operations has been based on few field data collection efforts and relied mostly on traffic simulation efforts. In the : 2010 Manual heavy ...

Monitoring and assessing global impacts of roads and off-road vehicle traffic

USDA-ARS?s Scientific Manuscript database

Rapid increases in the number of vehicles, urban sprawl, exurban development and infrastructure development for energy and water have led to dramatic increases in both the size and extent of the global road network. Anecdotal evidence suggests that off-road vehicle traffic has also increased in many...

Development and Evaluation of Model Algorithms to Account for Chemical Transformation in the Nearroad Environment

EPA Science Inventory

We describe the development and evaluation of two new model algorithms for NOx chemistry in the R-LINE near-road dispersion model for traffic sources. With increased urbanization, there is increased mobility leading to higher amount of traffic related activity on a global scale. ...

Environmental Assessment: Sooner Drop Zone Expansion Altus Air Force Base, Oklahoma

DTIC Science & Technology

2003-08-01

AND OUTDOOR NOISE SOURCES NOISE LEVEL (dBA) COMMON INDOOR NOISE LEVELS COMMON OUTDOOR NOISE LEVELS Jet Flyover at 1000 ft. Gas Lawn Mower at 3 ft...Diesel Truck at 50 ft. Noise Urban Daytime Gas Lawn Mower at 100 ft. Commercial Area Heavy Traffic at 300 ft. Quiet Urban Daytime Quiet Urban Nighttime

Environmental Assessment: Anti-Terrorism/Force Protection at Grand Forks Air Force Base, North Dakota

DTIC Science & Technology

2003-09-01

OUTDOOR NOISE SOURCES NOISE LEVEL (dBA) COMMON INDOOR NOISE LEVELS COMMON OUTDOOR NOISE LEVELS Gas Lawn Mower at 3 ft. Diesel Truck at 50 ft. Noise...Urban Daytime Gas Lawn Mower at 100 ft. Commercial Area Heavy Traffic at 300 ft. Quiet Urban Daytime Quiet Urban Nighttime Quiet Rural Nighttime Quiet

Environmental Assessment: Military Housing Privatization Initiative at Scott Air Force Base, Illinois

DTIC Science & Technology

2005-09-01

OUTDOOR NOISE SOURCES NOISE LEVEL (dBA) COMMON INDOOR NOISE LEVELS COMMON OUTDOOR NOISE LEVELS Gas Lawn Mower at 3 ft. Diesel Truck at 50 ft. Noise...Urban Daytime Gas Lawn Mower at 100 ft. Commercial Area Heavy Traffic at 300 ft. Quiet Urban Daytime Quiet Urban Nighttime Quiet Rural Nighttime Quiet

Intelligent lightening system of urban and rural road traffic based on pyroelectric infrared detector

NASA Astrophysics Data System (ADS)

Miao, Man-Xiang

2007-12-01

By using the photo-voltage characteristics of pyroelectric infrared detector to fulfill signal acquisition, the detecting signal is processed with the core of a single chip microprocessor AT89C51. AT89C51 controls the CAN bus controller SJA1000/transceiver 82C250 to structure CAN bus communication system to transmit data through serial interface MAX232 connected with PC. The intelligent lightening system of urban and rural road traffic was carried out. In this paper, its construction and part's methods of hardware and software design were introduced in detail.

Higher fuel prices are associated with lower air pollution levels.

PubMed

Barnett, Adrian G; Knibbs, Luke D

2014-05-01

Air pollution is a persistent problem in urban areas, and traffic emissions are a major cause of poor air quality. Policies to curb pollution levels often involve raising the price of using private vehicles, for example, congestion charges. We were interested in whether higher fuel prices were associated with decreased air pollution levels. We examined an association between diesel and petrol prices and four traffic-related pollutants in Brisbane from 2010 to 2013. We used a regression model and examined pollution levels up to 16 days after the price change. Higher diesel prices were associated with statistically significant short-term reductions in carbon monoxide and nitrogen oxides. Changes in petrol prices had no impact on air pollution. Raising diesel taxes in Australia could be justified as a public health measure. As raising taxes is politically unpopular, an alternative political approach would be to remove schemes that put a downward pressure on fuel prices, such as industry subsidies and shopping vouchers that give fuel discounts. Copyright © 2014 Elsevier Ltd. All rights reserved.

Investigation of CO2 emission reduction strategy from in-use gasoline vehicle

NASA Astrophysics Data System (ADS)

Choudhary, Arti; Gokhale, Sharad

2016-04-01

On road transport emissions is kicking off in Indian cities due to high levels of urbanization and economic growth during the last decade in Indian subcontinent. In 1951, about 17% of India's population were living in urban areas that increased to 32% in 2011. Currently, India is fourth largest Green House Gas (GHG) emitter in the world, with its transport sector being the second largest contributor of CO2 emissions. For achieving prospective carbon reduction targets, substantial opportunity among in-use vehicle is necessary to quantify. Since, urban traffic flow and operating condition has significant impact on exhaust emission (Choudhary and Gokhale, 2016). This study examined the influence of vehicular operating kinetics on CO2 emission from predominant private transportation vehicles of Indian metropolitan city, Guwahati. On-board instantaneous data were used to quantify the impact of CO2 emission on different mileage passenger cars and auto-rickshaws at different times of the day. Further study investigates CO2 emission reduction strategies by using International Vehicle Emission (IVE) model to improve co-benefit in private transportation by integrated effort such as gradual phase-out of inefficient vehicle and low carbon fuel. The analysis suggests that fuel type, vehicles maintenance and traffic flow management have potential for reduction of urban sector GHG emissions. Keywords: private transportation, CO2, instantaneous emission, IVE model Reference Choudhary, A., Gokhale, S. (2016). Urban real-world driving traffic emissions during interruption and congestion. Transportation Research Part D: Transport and Environment 43: 59-70.

Assessing the air quality impact of nitrogen oxides and benzene from road traffic and domestic heating and the associated cancer risk in an urban area of Verona (Italy)

NASA Astrophysics Data System (ADS)

Schiavon, Marco; Redivo, Martina; Antonacci, Gianluca; Rada, Elena Cristina; Ragazzi, Marco; Zardi, Dino; Giovannini, Lorenzo

2015-11-01

Simulations of emission and dispersion of nitrogen oxides (NOx) are performed in an urban area of Verona (Italy), characterized by street canyons and typical sources of urban pollutants. Two dominant source categories are considered: road traffic and, as an element of novelty, domestic heaters. Also, to assess the impact of urban air pollution on human health and, in particular, the cancer risk, simulations of emission and dispersion of benzene are carried out. Emissions from road traffic are estimated by the COPERT 4 algorithm, whilst NOx emission factors from domestic heaters are retrieved by means of criteria provided in the technical literature. Then maps of the annual mean concentrations of NOx and benzene are calculated using the AUSTAL2000 dispersion model, considering both scenarios representing the current situation, and scenarios simulating the introduction of environmental strategies for air pollution mitigation. The simulations highlight potentially critical situations of human exposure that may not be detected by the conventional network of air quality monitoring stations. The proposed methodology provides a support for air quality policies, such as planning targeted measurement campaigns, re-locating monitoring stations and adopting measures in favour of better air quality in urban planning. In particular, the estimation of the induced cancer risk is an important starting point to conduct zoning analyses and to detect the areas where population is more directly exposed to potential risks for health.

Neural networks for continuous online learning and control.

PubMed

Choy, Min Chee; Srinivasan, Dipti; Cheu, Ruey Long

2006-11-01

This paper proposes a new hybrid neural network (NN) model that employs a multistage online learning process to solve the distributed control problem with an infinite horizon. Various techniques such as reinforcement learning and evolutionary algorithm are used to design the multistage online learning process. For this paper, the infinite horizon distributed control problem is implemented in the form of real-time distributed traffic signal control for intersections in a large-scale traffic network. The hybrid neural network model is used to design each of the local traffic signal controllers at the respective intersections. As the state of the traffic network changes due to random fluctuation of traffic volumes, the NN-based local controllers will need to adapt to the changing dynamics in order to provide effective traffic signal control and to prevent the traffic network from becoming overcongested. Such a problem is especially challenging if the local controllers are used for an infinite horizon problem where online learning has to take place continuously once the controllers are implemented into the traffic network. A comprehensive simulation model of a section of the Central Business District (CBD) of Singapore has been developed using PARAMICS microscopic simulation program. As the complexity of the simulation increases, results show that the hybrid NN model provides significant improvement in traffic conditions when evaluated against an existing traffic signal control algorithm as well as a new, continuously updated simultaneous perturbation stochastic approximation-based neural network (SPSA-NN). Using the hybrid NN model, the total mean delay of each vehicle has been reduced by 78% and the total mean stoppage time of each vehicle has been reduced by 84% compared to the existing traffic signal control algorithm. This shows the efficacy of the hybrid NN model in solving large-scale traffic signal control problem in a distributed manner. Also, it indicates the possibility of using the hybrid NN model for other applications that are similar in nature as the infinite horizon distributed control problem.

Applying Graph Theory to Problems in Air Traffic Management

NASA Technical Reports Server (NTRS)

Farrahi, Amir Hossein; Goldbert, Alan; Bagasol, Leonard Neil; Jung, Jaewoo

2017-01-01

Graph theory is used to investigate three different problems arising in air traffic management. First, using a polynomial reduction from a graph partitioning problem, it is shown that both the airspace sectorization problem and its incremental counterpart, the sector combination problem are NP-hard, in general, under several simple workload models. Second, using a polynomial time reduction from maximum independent set in graphs, it is shown that for any fixed e, the problem of finding a solution to the minimum delay scheduling problem in traffic flow management that is guaranteed to be within n1-e of the optimal, where n is the number of aircraft in the problem instance, is NP-hard. Finally, a problem arising in precision arrival scheduling is formulated and solved using graph reachability. These results demonstrate that graph theory provides a powerful framework for modeling, reasoning about, and devising algorithmic solutions to diverse problems arising in air traffic management.

Applying Graph Theory to Problems in Air Traffic Management

NASA Technical Reports Server (NTRS)

Farrahi, Amir H.; Goldberg, Alan T.; Bagasol, Leonard N.; Jung, Jaewoo

2017-01-01

Graph theory is used to investigate three different problems arising in air traffic management. First, using a polynomial reduction from a graph partitioning problem, it isshown that both the airspace sectorization problem and its incremental counterpart, the sector combination problem are NP-hard, in general, under several simple workload models. Second, using a polynomial time reduction from maximum independent set in graphs, it is shown that for any fixed e, the problem of finding a solution to the minimum delay scheduling problem in traffic flow management that is guaranteed to be within n1-e of the optimal, where n is the number of aircraft in the problem instance, is NP-hard. Finally, a problem arising in precision arrival scheduling is formulated and solved using graph reachability. These results demonstrate that graph theory provides a powerful framework for modeling, reasoning about, and devising algorithmic solutions to diverse problems arising in air traffic management.

The relationship between urban combined traffic noise and annoyance: an investigation in Dalian, north of China.

PubMed

Di, Guoqing; Liu, Xiaoyi; Lin, Qili; Zheng, Yue; He, Lingjiao

2012-08-15

Several residential areas in Dalian, north of China, were selected to investigate the influence of combined traffic noise pollution on urban residents. The software Cadna/A was used to estimate the day-night equivalent noise level (L(dn)) at 1m from the windows of each building, which were modified according to the actual data. Annoyance has been identified as the most important psychological impact of noise. A face-to-face survey on annoyance was carried out among 1536 local residents between the ages of 15 and 75 years. In this study, the relationship between the percentage of "highly annoyed" persons (%HA) and L(dn) was determined. The L(dn) was measured and identified as railway dominant noise, road traffic dominant noise or road-rail combined traffic noise. We find that when L(dn)>63.5 dB, the %HA due to the road-rail combined traffic noise was significantly higher than that due to the one dominant noise source with the same L(dn). Thus, it is suggested that the planning permission buildings whose L(dn) of road-rail combined traffic noise exceeds 63.5-dB be reviewed more strictly. The relationships between %HA induced by different traffic noise and the distance to transportation artery (s) were analyzed. The results showed that as the distance to transportation artery increased, the %HA due to different traffic noise gradually decreased. Furthermore, the %HA due to the road traffic dominant noise at close range (1 m≤s≤50 m) was lower than that at a more remote location (51 m≤s≤100 m), which might be ascribed to the greater tolerance of the noise by the residents. Copyright © 2012 Elsevier B.V. All rights reserved.

Urban roadway congestion : annual report

DOT National Transportation Integrated Search

1998-01-01

The annual traffic congestion study is an effort to monitor roadway congestion in major urban areas in the United States. The comparisons to other areas and to previous experiences in each area are facilitated by a database that begins in 1982 and in...

Integrative freight demand management in the New York City metropolitan area : implementation phase.

DOT National Transportation Integrated Search

2013-09-01

Urban freight transportation is crucial to the quality of modern life, though at the same time it : produces significant negative externalities. Despite the relatively small proportion of freight with respect : to all traffic, urban freight movements...

Climate change and developing-country cities: implications for environmental health and equity.

PubMed

Campbell-Lendrum, Diarmid; Corvalán, Carlos

2007-05-01

Climate change is an emerging threat to global public health. It is also highly inequitable, as the greatest risks are to the poorest populations, who have contributed least to greenhouse gas (GHG) emissions. The rapid economic development and the concurrent urbanization of poorer countries mean that developing-country cities will be both vulnerable to health hazards from climate change and, simultaneously, an increasing contributor to the problem. We review the specific health vulnerabilities of urban populations in developing countries and highlight the range of large direct health effects of energy policies that are concentrated in urban areas. Common vulnerability factors include coastal location, exposure to the urban heat-island effect, high levels of outdoor and indoor air pollution, high population density, and poor sanitation. There are clear opportunities for simultaneously improving health and cutting GHG emissions most obviously through policies related to transport systems, urban planning, building regulations and household energy supply. These influence some of the largest current global health burdens, including approximately 800,000 annual deaths from ambient urban air pollution, 1.2 million from road-traffic accidents, 1.9 million from physical inactivity, and 1.5 million per year from indoor air pollution. GHG emissions and health protection in developing-country cities are likely to become increasingly prominent in policy development. There is a need for a more active input from the health sector to ensure that development and health policies contribute to a preventive approach to local and global environmental sustainability, urban population health, and health equity.

Betweenness centrality and its applications from modeling traffic flows to network community detection

NASA Astrophysics Data System (ADS)

Ren, Yihui

As real-world complex networks are heterogeneous structures, not all their components such as nodes, edges and subgraphs carry the same role or importance in the functions performed by the networks: some elements are more critical than others. Understanding the roles of the components of a network is crucial for understanding the behavior of the network as a whole. One the most basic function of networks is transport; transport of vehicles/people, information, materials, forces, etc., and these quantities are transported along edges between source and destination nodes. For this reason, network path-based importance measures, also called centralities, play a crucial role in the understanding of the transport functions of the network and the network's structural and dynamical behavior in general. In this thesis we study the notion of betweenness centrality, which measures the fraction of lowest-cost (or shortest) paths running through a network component, in particular through a node or an edge. High betweenness centrality nodes/edges are those that will be frequently used by the entities transported through the network and thus they play a key role in the overall transport properties of the network. In the first part of the thesis we present a first-principles based method for traffic prediction using a cost-based generalization of the radiation model (emission/absorbtion model) for human mobility, coupled with a cost-minimizing algorithm for efficient distribution of the mobility fluxes through the network. Using US census and highway traffic data, we show that traffic can efficiently and accurately be computed from a range-limited, network betweenness type calculation. The model based on travel time costs captures the log-normal distribution of the traffic and attains a high Pearson correlation coefficient (0.75) when compared with real traffic. We then focus on studying the extent of changes in traffic flows in the wake of a localized damage or alteration to the network and we demonstrate that the changes can propagate globally, affecting traffic several hundreds of miles away. Because of its principled nature, this method can inform many applications related to human mobility driven flows in spatial networks, ranging from transportation, through urban planning to mitigation of the effects of catastrophic events. In the second part of the thesis we focus on network deconstruction and community detection problems, both intensely studied topics in network science, using a weighted betweenness centrality approach. We present an algorithm that solves both problems efficiently and accurately and demonstrate that on both benchmark networks and data networks.

Understanding re-distribution of road deposited particle-bound pollutants using a Bayesian Network (BN) approach.

PubMed

Liu, An; Wijesiri, Buddhi; Hong, Nian; Zhu, Panfeng; Egodawatta, Prasanna; Goonetilleke, Ashantha

2018-05-08

Road deposited pollutants (build-up) are continuously re-distributed by external factors such as traffic and wind turbulence, influencing stormwater runoff quality. However, current stormwater quality modelling approaches do not account for the re-distribution of pollutants. This undermines the accuracy of stormwater quality predictions, constraining the design of effective stormwater treatment measures. This study, using over 1000 data points, developed a Bayesian Network modelling approach to investigate the re-distribution of pollutant build-up on urban road surfaces. BTEX, which are a group of highly toxic pollutants, was the case study pollutants. Build-up sampling was undertaken in Shenzhen, China, using a dry and wet vacuuming method. The research outcomes confirmed that the vehicle type and particle size significantly influence the re-distribution of particle-bound BTEX. Compared to heavy-duty traffic in commercial areas, light-duty traffic dominates the re-distribution of particles of all size ranges. In industrial areas, heavy-duty traffic re-distributes particles >75 μm, and light-duty traffic re-distributes particles <75 μm. In residential areas, light-duty traffic re-distributes particles >300 μm and <75 μm and heavy-duty traffic re-distributes particles in the 300-150 μm range. The study results provide important insights to improve stormwater quality modelling and the interpretation of modelling outcomes, contributing to safeguard the urban water environment. Copyright © 2018 Elsevier B.V. All rights reserved.

The role of local urban traffic and meteorological conditions in air pollution: A data-based case study in Madrid, Spain

NASA Astrophysics Data System (ADS)

Laña, Ibai; Del Ser, Javier; Padró, Ales; Vélez, Manuel; Casanova-Mateo, Carlos

2016-11-01

Urban air pollution is a matter of growing concern for both public administrations and citizens. Road traffic is one of the main sources of air pollutants, though topography characteristics and meteorological conditions can make pollution levels increase or diminish dramatically. In this context an upsurge of research has been conducted towards functionally linking variables of such domains to measured pollution data, with studies dealing with up to one-hour resolution meteorological data. However, the majority of such reported contributions do not deal with traffic data or, at most, simulate traffic conditions jointly with the consideration of different topographical features. The aim of this study is to further explore this relationship by using high-resolution real traffic data. This paper describes a methodology based on the construction of regression models to predict levels of different pollutants (i.e. CO, NO, NO2, O3 and PM10) based on traffic data and meteorological conditions, from which an estimation of the predictive relevance (importance) of each utilized feature can be estimated by virtue of their particular training procedure. The study was made with one hour resolution meteorological, traffic and pollution historic data in roadside and background locations of the city of Madrid (Spain) captured over 2015. The obtained results reveal that the impact of vehicular emissions on the pollution levels is overshadowed by the effects of stable meteorological conditions of this city.

[A spatially explicit analysis of traffic accidents involving pedestrians and cyclists in Berlin].

PubMed

Lakes, Tobia

2017-12-01

In many German cities and counties, sustainable mobility concepts that strengthen pedestrian and cyclist traffic are promoted. From the perspectives of urban development, traffic planning and public healthcare, a spatially differentiated analysis of traffic accident data is decisive. 1) The identification of spatial and temporal patterns of the distribution of accidents involving cyclists and pedestrians, 2) the identification of hotspots and exploration of possible underlying causes and 3) the critical discussion of benefits and challenges of the results and the derivation of conclusions. Spatio-temporal distributions of data from accident statistics in Berlin involving pedestrians and cyclists from 2011 to 2015 were analysed with geographic information systems (GIS). While the total number of accidents remains relatively stable for pedestrian and cyclist accidents, the spatial distribution analysis shows, however, that there are significant spatial clusters (hotspots) of traffic accidents with a strong concentration in the inner city area. In a critical discussion, the benefits of geographic concepts are identified, such as spatially explicit health data (in this case traffic accident data), the importance of the integration of other data sources for the evaluation of the health impact of areas (traffic accident statistics of the police), and the possibilities and limitations of spatial-temporal data analysis (spatial point-density analyses) for the derivation of decision-supported recommendations and for the evaluation of policy measures of health prevention and of health-relevant urban development.

A regression-based method for mapping traffic-related air pollution: application and testing in four contrasting urban environments.

PubMed

Briggs, D J; de Hoogh, C; Gulliver, J; Wills, J; Elliott, P; Kingham, S; Smallbone, K

2000-05-15

Accurate, high-resolution maps of traffic-related air pollution are needed both as a basis for assessing exposures as part of epidemiological studies, and to inform urban air-quality policy and traffic management. This paper assesses the use of a GIS-based, regression mapping technique to model spatial patterns of traffic-related air pollution. The model--developed using data from 80 passive sampler sites in Huddersfield, as part of the SAVIAH (Small Area Variations in Air Quality and Health) project--uses data on traffic flows and land cover in the 300-m buffer zone around each site, and altitude of the site, as predictors of NO2 concentrations. It was tested here by application in four urban areas in the UK: Huddersfield (for the year following that used for initial model development), Sheffield, Northampton, and part of London. In each case, a GIS was built in ArcInfo, integrating relevant data on road traffic, urban land use and topography. Monitoring of NO2 was undertaken using replicate passive samplers (in London, data were obtained from surveys carried out as part of the London network). In Huddersfield, Sheffield and Northampton, the model was first calibrated by comparing modelled results with monitored NO2 concentrations at 10 randomly selected sites; the calibrated model was then validated against data from a further 10-28 sites. In London, where data for only 11 sites were available, validation was not undertaken. Results showed that the model performed well in all cases. After local calibration, the model gave estimates of mean annual NO2 concentrations within a factor of 1.5 of the actual mean (approx. 70-90%) of the time and within a factor of 2 between 70 and 100% of the time. r2 values between modelled and observed concentrations are in the range of 0.58-0.76. These results are comparable to those achieved by more sophisticated dispersion models. The model also has several advantages over dispersion modelling. It is able, for example, to provide high-resolution maps across a whole urban area without the need to interpolate between receptor points. It also offers substantially reduced costs and processing times compared to formal dispersion modelling. It is concluded that the model might thus be used as a means of mapping long-term air pollution concentrations either in support of local authority air-quality management strategies, or in epidemiological studies.

Performance of an Automated-Mixed-Traffic-Vehicle /AMTV/ System. [urban people mover

NASA Technical Reports Server (NTRS)

Peng, T. K. C.; Chon, K.

1978-01-01

This study analyzes the operation and evaluates the expected performance of a proposed automatic guideway transit system which uses low-speed Automated Mixed Traffic Vehicles (AMTV's). Vehicle scheduling and headway control policies are evaluated with a transit system simulation model. The effect of mixed-traffic interference on the average vehicle speed is examined with a vehicle-pedestrian interface model. Control parameters regulating vehicle speed are evaluated for safe stopping and passenger comfort.

[Trauma care - a global challenge. Experience gathered in a (trauma) center managing urban violence in Nigeria].

PubMed

Osmers, I; Winter, M; Krieger, S

2011-03-01

Internal fixation of fractures is an integral part of health care. However this is a privilege of the developed world. For humanitarian aid internal fixation has always been considered as too prone to infection given the poor hygienic conditions, too specialized, too costly and the infrastructure of so-called developing countries too weak to perform internal fixation successfully. Due to the globally increasing density of road traffic an alarming increase in victims of road traffic accidents can be observed. The World Health Organization (WHO) estimates that in 2030 road traffic accidents will be responsible for twice as many deaths as caused by HIV/AIDS.Road traffic accidents are considered to be the new global epidemic. Since the victims are generally young, their rehabilitation has not only a humanitarian, but also an economic impact for low-income countries. The organization Doctors Without Borders (Médecins Sans Frontières; MSF) is not only providing surgical care for victims of violence in war and conflict regions, but has expanded its portfolio to include victims of road traffic accidents and started to perform internal fixation under good hygienic circumstances in closed fractures. The following is a report about the work in a hospital for surgical trauma care in Port Harcourt, Nigeria where victims of road traffic accidents are treated besides victims of urban violence.

Comparative analysis of the performance of One-Way and Two-Way urban road networks

NASA Astrophysics Data System (ADS)

Gheorghe, Carmen

2017-10-01

The fact that the number of vehicles is increasing year after year represents a challenge in road traffic management because it is necessary to adjust the road traffic, in order to prevent any incidents, using mostly the same road infrastructure. At this moment one-way road network provides efficient traffic flow for vehicles but it is not ideal for pedestrians. Therefore, a proper solution must be found and applied when and where it is necessary. Replacing one-way road network with two-way road network may be a viable solution especially if in the area is high pedestrian traffic. The paper aims to highlight the influence of both, one-way and two-way urban road networks through an experimental research which was performed by using traffic data collected in the field. Each of the two scenarios analyzed were based on the same traffic data, the same geometrical conditions of the road (lane width, total road segment width, road slopes, total length of the road network) and also the same signaling conditions (signalised intersection or roundabout). The analysis which involves two-way scenario reveals changes in the performance parameters like delay average, stops average, delay stop average and vehicle speed average. Based on the values obtained, it was possible to perform a comparative analysis between the real, one-way, scenario and the theoretical, two-way, scenario.

The formulation and implementation of a national helmet law: a case study from Viet Nam

PubMed Central

Nguyen, Lan Huong; Nguyen, Nam Phuong; Olivé, Jean-Marc

2010-01-01

Abstract Problem Road traffic injuries are a leading cause of death and disability in Viet Nam. In 2008, official data reported 11 243 deaths and 7771 serious injuries on the roads, of which an estimated 60% of fatalities occur in motorcycle riders and passengers. In recognition of this problem, Viet Nam has had partial motorcycle helmet legislation since 1995. However, for a variety of reasons, implementation and enforcement have been limited. Approach On 15 December 2007, Viet Nam's first comprehensive mandatory helmet law came into effect, covering all riders and passengers on all roads nationwide. Penalties increased ten-fold and cohorts of police were mobilized for enforcement. Local setting The Viet Nam national helmet legislation was developed and implemented by the National Traffic Safety Committee. Relevant changes Despite past barriers to enforcement, increased policing in 2008 led to 680 000 infringements being issued for non-helmet wearing. While changes in helmet wearing were not nationally observed, significant increases were documented in selected provinces in the first six months of the law’s introduction. In Da Nang, helmet wearing increased from 27 to 99%. In the first three months after the law took effect, surveillance data from 20 urban and rural hospitals, found the risk of road traffic head injuries and deaths decreased by 16% and 18% respectively. Lessons learnt Political leadership, intensive advanced public education and stringent enforcement have contributed to the successful implementation of the new law. Through continual monitoring of the legislation, loopholes detrimental to the effectiveness of the law have been identified and addressed. PMID:20931064

Research notes : adjustment of driver behavior to an urban multilane roundabout.

DOT National Transportation Integrated Search

2007-06-01

In June of 2006, the City of Springfield, Oregon began construction of the first multi-lane urban roundabout in Oregon. The five-legged roundabout replaced an existing T intersection that was controlled by a traffic light. A study was conducted...

Assessing segment- and corridor-based travel-time reliability on urban freeways : final report.

DOT National Transportation Integrated Search

2016-09-01

Travel time and its reliability are intuitive performance measures for freeway traffic operations. The objective of this project was to quantify segment-based and corridor-based travel time reliability measures on urban freeways. To achieve this obje...

Real-time optimization of passenger collection for commuter rail systems.

DOT National Transportation Integrated Search

2014-09-01

Commuter rail systems are being introduced into many urban areas as an alternative mode to automobiles : for commuting trips. The shift from the auto mode to rail mode is anticipated to greatly help alleviate : traffic congestion in urban road networ...

Estimating and incorporating CO2 emissions and associated fuel consumption into the Urban Mobility Report.

DOT National Transportation Integrated Search

2013-03-01

TTIs Urban Mobility Report (UMR) is acknowledged as the most authoritative source of information about traffic congestion : and its possible solutions. As policymakers from the local to national levels devise strategies to reduce greenhouse gas : ...

Exposure and toxicity assessment of ultrafine particles from nearby traffic in urban air in seoul, Korea.

PubMed

Yang, Ji-Yeon; Kim, Jin-Yong; Jang, Ji-Young; Lee, Gun-Woo; Kim, Soo-Hwan; Shin, Dong-Chun; Lim, Young-Wook

2013-01-01

We investigated the particle mass size distribution and chemical properties of air pollution particulate matter (PM) in the urban area and its capacity to induce cytotoxicity in human bronchial epithelial (BEAS-2B) cells. To characterize the mass size distributions and chemical concentrations associated with urban PM, PM samples were collected by a 10-stage Micro-Orifice Uniform Deposit Impactor close to nearby traffic in an urban area from December 2007 to December 2009. PM samples for in vitro cytotoxicity testing were collected by a mini-volume air sampler with PM10 and PM2.5 inlets. The PM size distributions were bi-modal, peaking at 0.18 to 0.32 and 1.8 to 3.2 µm. The mass concentrations of the metals in fine particles (0.1 to 1.8 µm) accounted for 45.6 to 80.4% of the mass concentrations of metals in PM10. The mass proportions of fine particles of the pollutants related to traffic emission, lead (80.4%), cadmium (69.0%), and chromium (63.8%) were higher than those of other metals. Iron was the dominant transition metal in the particles, accounting for 64.3% of the PM10 mass in all the samples. We observed PM concentration-dependent cytotoxic effects on BEAS-2B cells. We found that exposure to PM2.5 and PM10 from a nearby traffic area induced significant increases in protein expression of inflammatory cytokines (IL-6 and IL-8). The cell death rate and release of cytokines in response to the PM2.5 treatment were higher than those with PM10. The combined results support the hypothesis that ultrafine particles from vehicular sources can induce inflammatory responses related to environmental respiratory injury.

Unmanned Aircraft Systems Traffic Management (UTM) Safely Enabling UAS Operations in Low-Altitude Airspace

NASA Technical Reports Server (NTRS)

Kopardekar, Parimal H.

2017-01-01

Conduct research, development and testing to identify airspace operations requirements to enable large-scale visual and beyond visual line of sight UAS operations in the low-altitude airspace. Use build-a-little-test-a-little strategy remote areas to urban areas Low density: No traffic management required but understanding of airspace constraints. Cooperative traffic management: Understanding of airspace constraints and other operations. Manned and unmanned traffic management: Scalable and heterogeneous operations. UTM construct consistent with FAAs risk-based strategy. UTM research platform is used for simulations and tests. UTM offers path towards scalability

Turbulence influence on urban air pollution in a hot spot in Madrid: comparison of winter and summer field campaigns

NASA Astrophysics Data System (ADS)

Yagüe, Carlos; Román-Cascón, Carlos; Sastre, Mariano; Maqueda, Gregorio; Arrillaga, Jon A.; Artiñano, Begoña; Díaz-Ramiro, Elías; Gómez-Moreno, Francisco J.; Borge, Rafael; Narros, Adolfo; Pérez, Javier; Quaassdorff, Christina

2017-04-01

Air pollution is a major problem in the city of Madrid during weak synoptic forcing, since the presence of atmospheric stability conditions often develops night surface-based thermal inversions and subsidence inversions during daytime for several consecutive days, reaching high levels of NOx and Particulate Matter (PM) concentration. In this context, the TECNAIRE-CM (Innovative technologies for the assessment and improvement of urban air quality) research project has developed two field campaigns along 2015 (winter and summer) in a hot spot in the city of Madrid (Fernández Ladreda square). This hot spot includes one important intersection of different streets and also the start of the A42 motorway, which crosses down the square through a tunnel of about 150 m length. Besides, the location has numerous traffic lights and a lot of pedestrians walking in the vicinity. In addition to direct measurements related to air quality, data from different meteorological variables were recorded in order to characterize the atmospheric conditions. Moreover, two sonic anemometers where deployed to carry out a micrometeorological assessment of physical processes that take place in the urban atmospheric surface layer (TKE, friction velocity and sensible heat flux were evaluated). The evolution of the turbulence will be analyzed and compared for both campaigns (winter and summer), searching for the key seasonal differences as well as the importance of the different scales influencing the diffusion of pollutants (from multi resolution flux decomposition -MRFD- analysis). Specific case studies corresponding to high levels of pollution will be studied in detailed, to understand local pollution dynamics under the influence of both high traffic density and low turbulence situations. This work has been financed by Madrid Regional Research Plan through TECNAIRE (P2013/MAE-2972).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nyhan, Marguerite; Sobolevsky, Stanislav; Kang, Chaogui

Air pollution related to traffic emissions pose an especially significant problem in cities; this is due to its adverse impact on human health and well-being. Previous studies which have aimed to quantify emissions from the transportation sector have been limited by either simulated or coarsely resolved traffic volume data. Emissions inventories form the basis of urban pollution models, therefore in this study, Global Positioning System (GPS) trajectory data from a taxi fleet of over 15,000 vehicles were analyzed with the aim of predicting air pollution emissions for Singapore. This novel approach enabled the quantification of instantaneous drive cycle parameters inmore » high spatio-temporal resolution, which provided the basis for a microscopic emissions model. Carbon dioxide (CO2), nitrogen oxides (NOx), volatile organic compounds (VOCs) and particulate matter (PM) emissions were thus estimated. Highly localized areas of elevated emissions levels were identified, with a spatio-temporal precision not possible with previously used methods for estimating emissions. Relatively higher emissions areas were mainly concentrated in a few districts that were the Singapore Downtown Core area, to the north of the central urban region and to the east of it. Daily emissions quantified for the total motor vehicle population of Singapore were found to be comparable to another emissions dataset Results demonstrated that high resolution spatio-temporal vehicle traces detected using GPS in large taxi fleets could be used to infer highly localized areas of elevated acceleration and air pollution emissions in cities, and may become a complement to traditional emission estimates, especially in emerging cities and countries where reliable fine-grained urban air quality data is not easily available. This is the first study of its kind to investigate measured microscopic vehicle movement in tandem with microscopic emissions modeling for a substantial study domain.« less

Effects of urban density on carbon dioxide exchanges: Observations of dense urban, suburban and woodland areas of southern England.

PubMed

Ward, H C; Kotthaus, S; Grimmond, C S B; Bjorkegren, A; Wilkinson, M; Morrison, W T J; Evans, J G; Morison, J I L; Iamarino, M

2015-03-01

Anthropogenic and biogenic controls on the surface-atmosphere exchange of CO2 are explored for three different environments. Similarities are seen between suburban and woodland sites during summer, when photosynthesis and respiration determine the diurnal pattern of the CO2 flux. In winter, emissions from human activities dominate urban and suburban fluxes; building emissions increase during cold weather, while traffic is a major component of CO2 emissions all year round. Observed CO2 fluxes reflect diurnal traffic patterns (busy throughout the day (urban); rush-hour peaks (suburban)) and vary between working days and non-working days, except at the woodland site. Suburban vegetation offsets some anthropogenic emissions, but 24-h CO2 fluxes are usually positive even during summer. Observations are compared to estimated emissions from simple models and inventories. Annual CO2 exchanges are significantly different between sites, demonstrating the impacts of increasing urban density (and decreasing vegetation fraction) on the CO2 flux to the atmosphere. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

The Sustainable Expression of Ecological Concept in the Urban Landscape Environment Design

NASA Astrophysics Data System (ADS)

Dong, Junyan; Zhou, Tiejun; Xin, Lisen; Tan, Yuetong; Wang, Zhigang

2018-02-01

Urbanization is an inevitable trend of development of human society, also the inevitable outcome of economic development and scientific and technological progress, while urbanization process in promoting the development of human civilization, also no doubt, urban landscape has been a corresponding impact. Urban environment has suffered unprecedented damage, the urban population density, traffic congestion, shortage of resources, environmental pollution, ecological degradation, has become the focus of human society. In order to create an environment of ecological and harmonious, beautiful, sustainable development in the urban landscape, This paper discusses the concept of ecological design combined with the urban landscape design and sustainable development of urban landscape design.

Mining spatiotemporal patterns of urban dwellers from taxi trajectory data

NASA Astrophysics Data System (ADS)

Mao, Feng; Ji, Minhe; Liu, Ting

2016-06-01

With the widespread adoption of locationaware technology, obtaining long-sequence, massive and high-accuracy spatiotemporal trajectory data of individuals has become increasingly popular in various geographic studies. Trajectory data of taxis, one of the most widely used inner-city travel modes, contain rich information about both road network traffic and travel behavior of passengers. Such data can be used to study the microscopic activity patterns of individuals as well as the macro system of urban spatial structures. This paper focuses on trajectories obtained from GPS-enabled taxis and their applications for mining urban commuting patterns. A novel approach is proposed to discover spatiotemporal patterns of household travel from the taxi trajectory dataset with a large number of point locations. The approach involves three critical steps: spatial clustering of taxi origin-destination (OD) based on urban traffic grids to discover potentially meaningful places, identifying threshold values from statistics of the OD clusters to extract urban jobs-housing structures, and visualization of analytic results to understand the spatial distribution and temporal trends of the revealed urban structures and implied household commuting behavior. A case study with a taxi trajectory dataset in Shanghai, China is presented to demonstrate and evaluate the proposed method.

Birds and anthropogenic noise: are urban songs adaptive?

PubMed

Nemeth, Erwin; Brumm, Henrik

2010-10-01

In cities with intense low-frequency traffic noise, birds have been observed to sing louder and at a higher pitch. Several studies argue that higher song pitch is an adaptation to reduce masking from noise, and it has even been suggested that the song divergence between urban and nonurban songs might lead to reproductive isolation. Here we present models of signal transmission to compare the benefits of raised song amplitude and song pitch in terms of sound transmission. We chose two bird species that sing with higher pitch in urban areas, the great tit (Parus major) and the blackbird (Turdus merula). For both species, we calculated communication distances in response to different levels of urban noise and in their natural forest habitats. We found that an increase in vocal pitch increased communication distance only marginally. In contrast, vocal amplitude adjustments had a strong and significantly larger effect. Our results indicate that frequency changes of urban songs are not very effective in mitigating masking from traffic noise. Increased song pitch might not be an adaptation to reduce signal masking but a physiological side effect of singing at high amplitudes or an epiphenomenon of urbanization that is not related to signal transmission.

Safety analysis of urban arterials at the meso level.

PubMed

Li, Jia; Wang, Xuesong

2017-11-01

Urban arterials form the main structure of street networks. They typically have multiple lanes, high traffic volume, and high crash frequency. Classical crash prediction models investigate the relationship between arterial characteristics and traffic safety by treating road segments and intersections as isolated units. This micro-level analysis does not work when examining urban arterial crashes because signal spacing is typically short for urban arterials, and there are interactions between intersections and road segments that classical models do not accommodate. Signal spacing also has safety effects on both intersections and road segments that classical models cannot fully account for because they allocate crashes separately to intersections and road segments. In addition, classical models do not consider the impact on arterial safety of the immediately surrounding street network pattern. This study proposes a new modeling methodology that will offer an integrated treatment of intersections and road segments by combining signalized intersections and their adjacent road segments into a single unit based on road geometric design characteristics and operational conditions. These are called meso-level units because they offer an analytical approach between micro and macro. The safety effects of signal spacing and street network pattern were estimated for this study based on 118 meso-level units obtained from 21 urban arterials in Shanghai, and were examined using CAR (conditional auto regressive) models that corrected for spatial correlation among the units within individual arterials. Results showed shorter arterial signal spacing was associated with higher total and PDO (property damage only) crashes, while arterials with a greater number of parallel roads were associated with lower total, PDO, and injury crashes. The findings from this study can be used in the traffic safety planning, design, and management of urban arterials. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biomonitoring of genotoxic effects and elemental accumulation derived from air pollution in community urban gardens.

PubMed

Amato-Lourenco, Luís Fernando; Lobo, Debora Jã A; Guimarães, Eliane T; Moreira, Tiana Carla Lopes; Carvalho-Oliveira, Regiani; Saiki, Mitiko; Saldiva, Paulo Hilário Nascimento; Mauad, Thais

2017-01-01

Urban gardening is a growing global phenomenon with a positive impact on society. Despite several associated benefits, growing vegetables in urban gardens that are localized in highly polluted areas poses questions about the safety of the produced food. Therefore, the identification of risk factors that result in possible deleterious effects to human health is important for realizing all of the benefits to society. We evaluated the use of two biomonitoring methods in ten urban gardens of Sao Paulo city and one control site: the micronuclei frequencies for early tetrads of Tradescantia pallida (Rose) Hunt. cv. "Purpurea" Boom (hereafter, Trad-MCN) as a short-term indicator of genotoxic response and tree barks to quantify the accumulation of traffic-related chemical elements as a long-term biomarker of air pollution in urban gardens. Mature plants of Tradescantia pallida were exposed in each garden, and their inflorescences were sampled over three months. A random set of 300 early tetrads in 13 to 21 slides per garden were evaluated for micronuclei frequencies. Elemental concentrations in 428 tree barks samples from 107 different trees in the areas surrounding urban gardens were quantified using an energy dispersive X-ray fluorescence spectrometer. The frequency of Trad-MCN has a significant correlation with traffic variables and chemical elements related to road dust and tailpipe emissions deposited in tree barks. Negative associations between Trad-MCN and both the distance through traffic and the presence of vertical obstacles were observed in the community gardens. The Mn/Zn concentrations in tree barks were associated with increased Trad-MCN. Copyright © 2016 Elsevier B.V. All rights reserved.

Modeling exposures to traffic-related air pollutants for the NEXUS respiratory health study of asthmatic children in Detroit, MI

EPA Science Inventory

The Near-Road EXposures and Effects of Urban Air Pollutants Study (NEXUS) was designed to investigate associations between exposure to traffic-related air pollution and the respiratory health of asthmatic children living near major roadways in Detroit, MI. A combination of modeli...

SPRINGTIME SPATIAL CONCENTRATION GRADIENTS OF NITROGEN DIOXIDE AND VOLATILE ORGANIC SPECIES IN THE EL PASO CHILDREN'S HEALTH STUDY

EPA Science Inventory

Each year, over 18 million vehicles cross the international border between El Paso, TX (USA) and Ciudad Juarez (Mexico). The border traffic congestion, as well as the more typical intra-urban and interstate traffic, provide an opportunity to investigate the health effects of PM ...

Measurements and Analysis of Black Carbon Aerosols in the Eastern Mediterranean Megacity

NASA Astrophysics Data System (ADS)

Unal, A.; Ozdemir, H.; Kindap, T.; Demir, G.; Karaca, M.; Khan, M. N.

2010-12-01

In a world where at least 50 percent of the population is living in urban environments, air pollution and specifically particulate matter became one of the most critical issues. There have been many studies that focused on mass concentration measurements of PM10 and PM2.5. Recent studies suggest that chemical composition is critical in understanding the effects of PM on health as well as climate. For example, public health studies reveal that, components of the atmospheric aerosols have different impacts on human health. Smith et al. (2009) stated that; on the basis of the 1μg/m3 contrast, the percentage increase in all-cause mortality for PM2.5 was 0.58; sulfate effects were about twice those of PM2.5, and effects of elemental carbon (an indicator of black carbon mass) about ten times greater. To date, many studies and national inventories have been based on particulate matter (PM10 and PM2.5), and the major greenhouse pollutants, but not speciated emissions, especially in the developing world (Smith et al., 2009; Chow et al., 2010). But air quality standards will soon need to include particulate black carbon (BC), as it directly afffects climate, visibility, and human health. Anthropogenic emissions are increasing dramatically worldwide and recent estimates of global BC emissions range from 8 to 24 Tg (1012 g) per year. In this study, we investigated BC pollution for the first time in Istanbul, Turkey. Istanbul is a megacity of over 15 million inhabitants (OECD, 2008). On-road traffic is also increasing rapidly in the city (over 3 million vehicles on the road). Hence, the city has a potential to be an important source for both local and regional pollution in the Eastern Mediterranean. In our study, an Aethalometer (<0.1μg/m3 sensitivity) was used for continuous and real-time measurements of BC concentration. Measurements were carried out at the selected five different locations throughout the city. 1st and 2nd sites were near high-traffic streets; in the city center, and on the shore of the Bosphorus, respectively; 3rd was near a high way; 4th was located on an urban park (provided for recreational use); and 5th was on a low-traffic residential street. Mean BC aerosol mass concentrations were 5,500 ng/m3 and 7,600 ng/m3 during the study periods for 2009 (155 days), and 2010 (122 days), respectively. BC concentrations near dense traffic were found to reach higher values; average concentration at the 2nd site in 2010 was 8,400 ng/m3; at the 1st site in 2009 was 12,000 ng/m3. BC concentration measured in the urban park, which had very low traffic activity, was lower; 4,300 ng/m3, and 6,000 ng/m3 for 2009, and 2010, respectively. This paper will present findings on BC measurements and statistical analysis of temporal and spatial distributions of the BC concentrations to understand the origin of the BC problem in Istanbul. These findings will be essential in understanding the aerosol problem and developing mitigation measures to reduce public health risks associated with it.

Low Emissions and Delay Optimization for an Isolated Signalized Intersection Based on Vehicular Trajectories

PubMed Central

2015-01-01

A traditional traffic signal control system is established based on vehicular delay, queue length, saturation and other indicators. However, due to the increasing severity of urban environmental pollution issues and the development of a resource-saving and environmentally friendly social philosophy, the development of low-carbon and energy-efficient urban transport is required. This paper first defines vehicular trajectories and the calculation of vehicular emissions based on VSP. Next, a regression analysis method is used to quantify the relationship between vehicular emissions and delay, and a traffic signal control model is established to reduce emissions and delay using the enumeration method combined with saturation constraints. Finally, one typical intersection of Changchun is selected to verify the model proposed in this paper; its performance efficiency is also compared using simulations in VISSIM. The results of this study show that the proposed model can significantly reduce vehicle delay and traffic emissions simultaneously. PMID:26720095

Low Emissions and Delay Optimization for an Isolated Signalized Intersection Based on Vehicular Trajectories.

PubMed

Lin, Ciyun; Gong, Bowen; Qu, Xin

2015-01-01

A traditional traffic signal control system is established based on vehicular delay, queue length, saturation and other indicators. However, due to the increasing severity of urban environmental pollution issues and the development of a resource-saving and environmentally friendly social philosophy, the development of low-carbon and energy-efficient urban transport is required. This paper first defines vehicular trajectories and the calculation of vehicular emissions based on VSP. Next, a regression analysis method is used to quantify the relationship between vehicular emissions and delay, and a traffic signal control model is established to reduce emissions and delay using the enumeration method combined with saturation constraints. Finally, one typical intersection of Changchun is selected to verify the model proposed in this paper; its performance efficiency is also compared using simulations in VISSIM. The results of this study show that the proposed model can significantly reduce vehicle delay and traffic emissions simultaneously.

Solving "Smart City" Transport Problems by Designing Carpooling Gamification Schemes with Multi-Agent Systems: The Case of the So-Called "Mordor of Warsaw".

PubMed

Olszewski, Robert; Pałka, Piotr; Turek, Agnieszka

2018-01-06

To reduce energy consumption and improve residents' quality of life, "smart cities" should use not only modern technologies, but also the social innovations of the "Internet of Things" (IoT) era. This article attempts to solve transport problems in a smart city's office district by utilizing gamification that incentivizes the carpooling system. The goal of the devised system is to significantly reduce the number of cars, and, consequently, to alleviate traffic jams, as well as to curb pollution and energy consumption. A representative sample of the statistical population of people working in one of the biggest office hubs in Poland (the so-called "Mordor of Warsaw") was surveyed. The collected data were processed using spatial data mining methods, and the results were a set of parameters for the multi-agent system. This approach made it possible to run a series of simulations on a set of 100,000 agents and to select an effective gamification methodology that supports the carpooling process. The implementation of the proposed solutions (a "serious game" variation of urban games) would help to reduce the number of cars by several dozen percent, significantly reduce energy consumption, eliminate traffic jams, and increase the activity of the smart city residents.

Identification of Major Sources of Atmospheric NH3 in an Urban Environment in Northern China During Wintertime.

PubMed

Teng, Xiaolin; Hu, Qingjing; Zhang, Leiming; Qi, Jiajia; Shi, Jinhui; Xie, Huan; Gao, Huiwang; Yao, Xiaohong

2017-06-20

To assess the relative contributions of traffic emission and other potential sources to high levels of atmospheric ammonia (NH 3 ) in urban areas in the wintertime, atmospheric NH 3 and related pollutants were measured at an urban site, ∼300 m from a major traffic road, in northern China in November and December 2015. Hourly average NH 3 varied from 0.3 to 10.8 ppb with an average of 2.4 ppb during the campaign. Contrary to the common perspective in literature, traffic emission was demonstrated to be a negligible contributor to atmospheric NH 3 . Atmospheric NH 3 correlated well with ambient water vapor during many time periods lasting from tens of hours to several days, implying NH 3 released from water evaporation is an important source. Emissions from local green space inside the urban areas were identified to significantly contribute to the observed atmospheric NH 3 during ∼60% of the sampling times. Evaporation of predeposited NH x through wet precipitation combined with emissions from local green space likely caused the spikes of atmospheric NH 3 mostly occurring 1-4 h after morning rush hours or after and during slight shower events. There are still ∼30% of the data samples with appreciable NH 3 level for which major contributors are yet to be identified.

An Experimental Study of the Noise Due to Traffic in a Congested Urban Area

NASA Astrophysics Data System (ADS)

Sangeetha, M.; Sankar, P.

2016-03-01

Noise pollution in an urban environment is an issue of serious concern in the major cities of India. There are various factors that contribute to the increase of noise levels in urban areas. The intensity of traffic is one of the factors which contributes to a drastic increase in environmental noise. The management of noise pollution has to be considered in the decision making process. In this paper, an attempt is made to study the existing noise level due to the traffic in Velachery which is declared as a sensitive area by the Ministry of Environment and Forestry (MoEF). The noise level data is collected using the MS6710 digital sound meter. The Custic simulation software version 3.2 is used for finding the propagation of noise. The spatial patterns of measurement were also calculated, in the sub-urban area of Velachery, Chennai, Tamilnadu, India. A means of transmitting this data to vehicles moving in the area, through a wireless medium is simulated using NCTUns 6.0 (network simulator), to enable drivers to understand the environmental conditions. A hardware was also designed which can be used to transmit and receive the noise data using the Zigbee module. A noise transmitting station is placed at a junction, so that it can transmit this noise data to the receivers which are fitted inside the vehicles.

Human resources for the control of road traffic injury.

PubMed

Mock, Charles; Kobusingye, Olive; Anh, Le Vu; Afukaar, Francis; Arreola-Risa, Carlos

2005-04-01

The definition of the ideal numbers and distribution of human resources required for control of road traffic injury (RTI) is not as advanced as for other health problems. We can nonetheless identify functions that need to be addressed across the spectrum of injury control: surveillance; road safety (including infrastructure, vehicle design, and behaviour); and trauma care. Many low-cost strategies to improve these functions in low- or middle-income countries can be identified. For all these strategies, there is need for adequate institutional capacity, including funding, legal authority, and human resources. Several categories of human resources need to be developed: epidemiologists who can handle injury data, design surveillance systems, and undertake research; engineers and planners versed in safety aspects of road design, traffic flow, urban planning, and vehicle design; police and lawyers who understand the health impact of traffic law; clinicians who can develop cost-effective improvements in the entire system of trauma treatment; media experts to undertake effective behaviour change and social marketing; and economists to assist with cost-effectiveness evaluations. RTI control can be strengthened by enhancing such training in these disciplines, as well as encouraging retention of those who have the needed skills. Mechanisms to enhance collaboration between these different fields need to be promoted. Finally, the burden of RTI is borne disproportionately by the poor; in addition to technical issues, more profound equity issues must be addressed. This mandates that people from all professional backgrounds who work for RTI control should develop skills in advocacy and politics.

Human resources for the control of road traffic injury.

PubMed Central

Mock, Charles; Kobusingye, Olive; Anh, Le Vu; Afukaar, Francis; Arreola-Risa, Carlos

2005-01-01

The definition of the ideal numbers and distribution of human resources required for control of road traffic injury (RTI) is not as advanced as for other health problems. We can nonetheless identify functions that need to be addressed across the spectrum of injury control: surveillance; road safety (including infrastructure, vehicle design, and behaviour); and trauma care. Many low-cost strategies to improve these functions in low- or middle-income countries can be identified. For all these strategies, there is need for adequate institutional capacity, including funding, legal authority, and human resources. Several categories of human resources need to be developed: epidemiologists who can handle injury data, design surveillance systems, and undertake research; engineers and planners versed in safety aspects of road design, traffic flow, urban planning, and vehicle design; police and lawyers who understand the health impact of traffic law; clinicians who can develop cost-effective improvements in the entire system of trauma treatment; media experts to undertake effective behaviour change and social marketing; and economists to assist with cost-effectiveness evaluations. RTI control can be strengthened by enhancing such training in these disciplines, as well as encouraging retention of those who have the needed skills. Mechanisms to enhance collaboration between these different fields need to be promoted. Finally, the burden of RTI is borne disproportionately by the poor; in addition to technical issues, more profound equity issues must be addressed. This mandates that people from all professional backgrounds who work for RTI control should develop skills in advocacy and politics. PMID:15868021

Comparison of the operational and safety characteristics of the single point urban and diamond interchanges.

DOT National Transportation Integrated Search

1996-01-01

The purpose of this study was to evaluate and compare the safety and operational characteristics of the single point urban interchange (SPUI) and the diamond interchange (DI) and develop guidelines that identify traffic and/or geometric conditions th...

The Challenge of Urban Policy

ERIC Educational Resources Information Center

Glaeser, Edward L.

2012-01-01

Urbanization almost invariably accompanies development, and the cities of India and China are experiencing spectacular increases in population. The concentration of millions of people in a small mass creates challenges for public policy, especially in the areas of basic infrastructure, public health, traffic congestion, and often law enforcement…

The temporal structure of pollution levels in developed cities.

PubMed

Barrigón Morillas, Juan Miguel; Ortiz-Caraballo, Carmen; Prieto Gajardo, Carlos

2015-06-01

Currently, the need for mobility can cause significant pollution levels in cities, with important effects on health and quality of life. Any approach to the study of urban pollution and its effects requires an analysis of spatial distribution and temporal variability. It is a crucial dilemma to obtain proven methodologies that allow an increase in the quality of the prediction and the saving of resources in the spatial and temporal sampling. This work proposes a new analytical methodology in the study of temporal structure. As a result, a model for estimating annual levels of urban traffic noise was proposed. The average errors are less than one decibel in all acoustics indicators. A new working methodology of urban noise has begun. Additionally, a general application can be found for the study of the impacts of pollution associated with traffic, with implications for urban design and possibly in economic and sociological aspects. Copyright © 2015 Elsevier B.V. All rights reserved.

Ultrafine particles in cities.

PubMed

Kumar, Prashant; Morawska, Lidia; Birmili, Wolfram; Paasonen, Pauli; Hu, Min; Kulmala, Markku; Harrison, Roy M; Norford, Leslie; Britter, Rex

2014-05-01

Ultrafine particles (UFPs; diameter less than 100 nm) are ubiquitous in urban air, and an acknowledged risk to human health. Globally, the major source for urban outdoor UFP concentrations is motor traffic. Ongoing trends towards urbanisation and expansion of road traffic are anticipated to further increase population exposure to UFPs. Numerous experimental studies have characterised UFPs in individual cities, but an integrated evaluation of emissions and population exposure is still lacking. Our analysis suggests that the average exposure to outdoor UFPs in Asian cities is about four-times larger than that in European cities but impacts on human health are largely unknown. This article reviews some fundamental drivers of UFP emissions and dispersion, and highlights unresolved challenges, as well as recommendations to ensure sustainable urban development whilst minimising any possible adverse health impacts. Copyright © 2014 Elsevier Ltd. All rights reserved.

Encapsulating urban traffic rhythms into road networks.

PubMed

Wang, Junjie; Wei, Dong; He, Kun; Gong, Hang; Wang, Pu

2014-02-20

Using road GIS (geographical information systems) data and travel demand data for two U.S. urban areas, the dynamical driver sources of each road segment were located. A method to target road clusters closely related to urban traffic congestion was then developed to improve road network efficiency. The targeted road clusters show different spatial distributions at different times of a day, indicating that our method can encapsulate dynamical travel demand information into the road networks. As a proof of concept, when we lowered the speed limit or increased the capacity of road segments in the targeted road clusters, we found that both the number of congested roads and extra travel time were effectively reduced. In addition, the proposed modeling framework provided new insights on the optimization of transport efficiency in any infrastructure network with a specific supply and demand distribution.

Urban violence is the biggest cause of fatal work-related accidents in Brazil.

PubMed

Cordeiro, Ricardo; Luz, Verônica Gronau; Hennington, Élida Azevedo; Martins, Ana Cláudia Alves; Tófoli, Luís Fernando

2017-12-11

To quantify the occurrence of deaths directly associated with urban violence among fatal work-related accidents. Verbal autopsies were performed with the relatives and coworkers of residents of Campinas, state of São Paulo, Brazil, who died from external causes in 2015. We have also analyzed police reports and reports of the Legal Medical Institute related to these deaths. We have identified 82 fatal work-related accidents in Campinas in 2015, of which 25 were murders, 35 were traffic accidents not directly related to work activities, and three were suicides at work. The proportional mortality rate for homicides, traffic accidents, and suicides among fatal work-related accidents was estimated at 30.5%, 42.7%, and 3.7%, respectively. Urban violence accounted for three-fourths of the fatal work-related accidents recorded in the period studied.

Encapsulating Urban Traffic Rhythms into Road Networks

PubMed Central

Wang, Junjie; Wei, Dong; He, Kun; Gong, Hang; Wang, Pu

2014-01-01

Using road GIS (geographical information systems) data and travel demand data for two U.S. urban areas, the dynamical driver sources of each road segment were located. A method to target road clusters closely related to urban traffic congestion was then developed to improve road network efficiency. The targeted road clusters show different spatial distributions at different times of a day, indicating that our method can encapsulate dynamical travel demand information into the road networks. As a proof of concept, when we lowered the speed limit or increased the capacity of road segments in the targeted road clusters, we found that both the number of congested roads and extra travel time were effectively reduced. In addition, the proposed modeling framework provided new insights on the optimization of transport efficiency in any infrastructure network with a specific supply and demand distribution. PMID:24553203

Accumulation of Heavy Metals in Roadside Soil in Urban Area and the Related Impacting Factors.

PubMed

Wang, Meie; Zhang, Haizhen

2018-05-24

Heavy metal contamination in roadside soil due to traffic emission has been recognized for a long time. However, seldom has been reported regarding identification of critical factors influencing the accumulation of heavy metals in urban roadside soils due to the frequent disturbances such as the repair of damaged roads and green belt maintanance. Heavy metals in the roadside soils of 45 roads in Xihu district, Hangzhou city were investigated. Results suggested the accumulation of Cu, Pb, Cd, Cr, and Zn in roadside soil was affected by human activity. However, only two sites had Pb and Zn excessing the standards for residential areas, respectively, according to Chinese Environmental Quality Standards for soils. The concentrations of Cu, Pb, Cd, and Zn were significantly and positively correlated to soil pH and organic matter. An insignificant correlation between the age of the roads or vegetation cover types and the concentration of heavy metals was found although they were reported closely relating to the accumulation of heavy metals in roadside soils of highways. The highest Pb, Cd, and Cr taking place in sites with heavy traffic and significant differences in the concentrations of Cu, Pb, Cd, and Zn among the different categories of roads suggested the contribution of traffic intensity. However, it was difficult to establish a quantitative relationship between traffic intensity and the concentrations of heavy metals in the roadside soil. It could be concluded that impaction of traffic emission on the accumulation of heavy metals in roadside soils in urban area was slight and soil properties such as pH and organic matters were critical factors influencing the retention of heavy metals in soils.

Predicting residential indoor concentrations of nitrogen dioxide, fine particulate matter, and elemental carbon using questionnaire and geographic information system based data

NASA Astrophysics Data System (ADS)

Baxter, Lisa K.; Clougherty, Jane E.; Paciorek, Christopher J.; Wright, Rosalind J.; Levy, Jonathan I.

Previous studies have identified associations between traffic-related air pollution and adverse health effects. Most have used measurements from a few central ambient monitors and/or some measure of traffic as indicators of exposure, disregarding spatial variability and factors influencing personal exposure-ambient concentration relationships. This study seeks to utilize publicly available data (i.e., central site monitors, geographic information system, and property assessment data) and questionnaire responses to predict residential indoor concentrations of traffic-related air pollutants for lower socioeconomic status (SES) urban households. As part of a prospective birth cohort study in urban Boston, we collected indoor and outdoor 3-4 day samples of nitrogen dioxide (NO 2) and fine particulate matter (PM 2.5) in 43 low SES residences across multiple seasons from 2003 to 2005. Elemental carbon (EC) concentrations were determined via reflectance analysis. Multiple traffic indicators were derived using Massachusetts Highway Department data and traffic counts collected outside sampling homes. Home characteristics and occupant behaviors were collected via a standardized questionnaire. Additional housing information was collected through property tax records, and ambient concentrations were collected from a centrally located ambient monitor. The contributions of ambient concentrations, local traffic and indoor sources to indoor concentrations were quantified with regression analyses. PM 2.5 was influenced less by local traffic but had significant indoor sources, while EC was associated with traffic and NO 2 with both traffic and indoor sources. Comparing models based on covariate selection using p-values or a Bayesian approach yielded similar results, with traffic density within a 50 m buffer of a home and distance from a truck route as important contributors to indoor levels of NO 2 and EC, respectively. The Bayesian approach also highlighted the uncertanity in the models. We conclude that by utilizing public databases and focused questionnaire data we can identify important predictors of indoor concentrations for multiple air pollutants in a high-risk population.

Noise sensitivity and loudness derivative index for urban road traffic noise annoyance computation.

PubMed

Gille, Laure-Anne; Marquis-Favre, Catherine; Weber, Reinhard

2016-12-01

Urban road traffic composed of powered-two-wheelers (PTWs), buses, heavy, and light vehicles is a major source of noise annoyance. In order to assess annoyance models considering different acoustical and non-acoustical factors, a laboratory experiment on short-term annoyance due to urban road traffic noise was conducted. At the end of the experiment, participants were asked to rate their noise sensitivity and to describe the noise sequences they heard. This verbalization task highlights that annoyance ratings are highly influenced by the presence of PTWs and by different acoustical features: noise intensity, irregular temporal amplitude variation, regular amplitude modulation, and spectral content. These features, except irregular temporal amplitude variation, are satisfactorily characterized by the loudness, the total energy of tonal components and the sputtering and nasal indices. Introduction of the temporal derivative of loudness allows successful modeling of perceived amplitude variations. Its contribution to the tested annoyance models is high and seems to be higher than the contribution of mean loudness index. A multilevel regression is performed to assess annoyance models using selected acoustical indices and noise sensitivity. Three models are found to be promising for further studies that aim to enhance current annoyance models.

Genotoxic effects following exposure to air pollution in street vendors from a high-traffic urban area.

PubMed

Domingues, Érica Prado; Silva, Guilherme Gomes; Oliveira, Andrei Barbassa; Mota, Lorrany Marins; Santos, Vanessa Santana Vieira; de Campos, Edimar Olegário; Pereira, Boscolli Barbosa

2018-03-14

Workers in several occupational environments are exposed to pollutants. Street vendors, for example, typically work in a high-traffic urban environment and are exposed to numerous air pollutants, including genotoxic substances emitted by motor vehicles. This study examined the genotoxic effects of exposure to air pollution. We conducted cytological analyses to assess frequencies of micronucleated (MN) and binucleated (BN) cells in a sample of exfoliated oral mucosa cells. We compared street vendors and control subjects in the city of Uberlândia, Minas Gerais, Brazil, and also collected quantitative information on exposure conditions of all test subjects, including concentrations of particulate matter. We found street vendors to exhibit higher frequencies of MN cells compared to the control group. We evaluated the effects of possible confounding variables on MN frequencies, namely the body mass index (BMI), age, as well as smoking and alcohol habits. Multiple linear regression analysis found no significant effects of any of those variables. Our results suggest that continued exposure to air pollution from traffic represents a major source of genotoxicity and raises concerns regarding disease prevention not only in street vendors but also other groups of people working in urban environments.

Analysis of heavy metals in the re-suspended road dusts from different functional areas in Xi'an, China.

PubMed

Wang, Qian; Lu, Xinwei; Pan, Huiyun

2016-10-01

A study on heavy metal pollution was undertaken in the re-suspended road dusts from different functional areas in Xi'an City of China to investigate the impacts of human activities and land uses on urban environment. The concentrations of Co, Cr, Cu, Mn, Ni, Pb, V, and Zn were determined using X-ray fluorescence spectrometry, and their accumulations were analyzed using enrichment factor. Correlation analysis, principal component analysis, and cluster analysis, combined with the concentration property and enrichment factor, were used to identify the possible sources of heavy metals investigated. The investigated re-suspended road dusts had Co, Cr, Cu, Pb, and Zn concentrations higher than background levels. Samples from different functional areas had diverse heavy metal concentration levels. Co, Cr, Cu, Pb, and Zn presented moderate/significant enrichment in the samples. The source analyses indicated that Mn, Ni, V, Pb, and Zn had the mixed sources of nature and traffic, Cr and Cu mainly originated from traffic source, while Co was primarily derived from construction source. Traffic and construction activities had a significant impact on urban environment. This preliminary research provides a valuable basis for urban environment protection and management.

Some Considerations on the Problem of Non-Steady State Traffic Flow Optimization

DOT National Transportation Integrated Search

2007-01-01

Poor traffic signal timing accounts for an estimated 10 percent of all traffic delay about 300 million vehicle-hours on major roadways alone. Americans agree that this is a problem: one U.S. Department of Transportation (DOT) survey found tha...

Saving lives in road traffic—ethical aspects

PubMed Central

2009-01-01

Aim This article aims at giving an overview of five ethical problem areas relating to traffic safety, thereby providing a general framework for analysing traffic safety from an ethical perspective and encouraging further discussion concerning problems, policies and technology in this area. Subjects and methods The problems presented in the article are criminalisation, paternalism, privacy, justice and responsibility, and the reasons for choosing these are the following. First, they are all important areas in moral philosophy. Second, they are fairly general and it should be possible to categorise more specific problems under these headings. Ethical aspects of road traffic have not received the philosophical attention they deserve. Every year, more than 1 million people die globally in traffic accidents, and 20 to 50 million people are injured. Ninety per cent of the road traffic fatalities occur in low- and middle-income countries, where it is a growing problem. Politics, economics, culture and technology affect the number of fatalities and injuries, and the measures used to combat deaths in traffic as well as the role of road traffic should be ethically scrutinised. The topics are analysed and discussed from a moral-philosophical perspective, and the discussion includes both theory and applications. Results and conclusion The author concludes with some thoughts on how the ethical discussion can be included in the public debate on how to save lives in road traffic. People in industrialised societies are so used to road traffic that it is almost seen as part of nature. Consequently, we do not acknowledge that we can introduce change and that we can affect the role we have given road traffic and cars. By acknowledging the ethical aspects of road traffic and illuminating the way the choices society makes are ethically charged, it becomes clear that there are alternative ways to design the road traffic system. The most important general conclusion is that discussion concerning these alternative ways of designing the system should be encouraged. PMID:21088693

An analysis of 3105 Medico Legal Cases at Tertiary Care Hospital, Rawalpindi.

PubMed

Malik, Romana; Atif, Iffat; Rashid, Farah; Abbas, Maqbool

2017-01-01

Medico legal cases are essential component of medical practice and comprise most important constituent of emergencies. The reporting of such cases is imperative to recognize theirsocioeconomic burden on any country. The present study was conducted to scrutinize different categories of medico legal cases and characteristics of the victims at casualty department oftertiary care hospital Rawalpindi. The objective of the study was to find out the frequency ofvarious categories of medico legal cases and major characteristics ofvictims at tertiary care hospital, Rawalpindi. This was a cross-sectional study on 3105 registered cases in medico legal record of the casualty department of Benazir Bhutto hospital, Rawalpindi from January 2015 to December 2015. The hospital is located on the main road in densely populated central area of the city. The data wascollected on age, sex, month-wise distribution of various medico legal cases, weapon inflicting the injury, blunt trauma or physical assault, firearm injuries and road traffic accidents. The data thus obtained was analyzed using SPSS; observations were presented in tables and graphs. Out of all 3105 registered medico legal cases, reported cases caused by Road Traffic Accident 1230 (40%) followed by blunt injury or physical assault 966 (32%) cases, 19% by sharp weapons, 5% by poisoning, and 4% by firearm injuries. In our study out of 3105 cases, almost three quarter of victims (73%) were below 30 years of age, with a decreasing frequency beyond this age, males were predominantly inflicted 2516(81%) as compared to females 589 (19%). The reported road traffic accidents cases from urban areas were high (74%) as compared to those from rural locality (37%). In cases of blunt trauma, sharp weapon injuries and firearm injuries, there was a huge preponderance of victims from rural areas (65%), (62%) and 61% respectively, with urban cases constituting less. Road traffic injuries are one of the foremost causes of medico legal cases followed by blunt trauma and sharp weapon injuries. The emerging medico legal cases are neglected epidemic in most of the developing countries comprising a considerable public health problem.

Association between pre-eclampsia and locally derived traffic-related air pollution: a retrospective cohort study.

PubMed

Pereira, Gavin; Haggar, Fatima; Shand, Antonia W; Bower, Carol; Cook, Angus; Nassar, Natasha

2013-02-01

Pre-eclampsia is a common complication of pregnancy and is a major cause of fetal-maternal mortality and morbidity. Despite a number of plausible mechanisms by which air pollutants might contribute to this process, few studies have investigated the association between pre-eclampsia and traffic emissions, a major contributor to air pollution in urban areas. The authors investigated the association between traffic-related air pollution and risk of pre-eclampsia in a maternal population in the urban centre of Perth, Western Australia. The authors estimated maternal residential exposure to a marker for traffic-related air pollution (nitrogen dioxide, NO(2)) during pregnancy for 23 452 births using temporally adjusted land-use regression. Logistic regression was used to investigate associations with pre-eclampsia. Each IQR increase in levels of traffic-related air pollution in whole pregnancy and third trimester was associated with a 12% (1%-25%) and 30% (7%-58%) increased risk of pre-eclampsia, respectively. The largest effect sizes were observed for women aged younger than 20 years or 40 years or older, aboriginal women and women with pre-existing and gestational diabetes, for whom an IQR increase in traffic-related air pollution in whole pregnancy was associated with a 34% (5%-72%), 35% (0%-82%) and 53% (7%-219%) increase in risk of pre-eclampsia, respectively. Elevated exposure to traffic-related air pollution in pregnancy was associated with increased risk of pre-eclampsia. Effect sizes were highest for elevated exposures in third trimester and among younger and older women, aboriginal women and women with diabetes.

Temporal and spatial variation in allocating annual traffic activity across an urban region and implications for air quality assessments

PubMed Central

Batterman, Stuart

2015-01-01

Patterns of traffic activity, including changes in the volume and speed of vehicles, vary over time and across urban areas and can substantially affect vehicle emissions of air pollutants. Time-resolved activity at the street scale typically is derived using temporal allocation factors (TAFs) that allow the development of emissions inventories needed to predict concentrations of traffic-related air pollutants. This study examines the spatial and temporal variation of TAFs, and characterizes prediction errors resulting from their use. Methods are presented to estimate TAFs and their spatial and temporal variability and used to analyze total, commercial and non-commercial traffic in the Detroit, Michigan, U.S. metropolitan area. The variability of total volume estimates, quantified by the coefficient of variation (COV) representing the percentage departure from expected hourly volume, was 21, 33, 24 and 33% for weekdays, Saturdays, Sundays and holidays, respectively. Prediction errors mostly resulted from hour-to-hour variability on weekdays and Saturdays, and from day-to-day variability on Sundays and holidays. Spatial variability was limited across the study roads, most of which were large freeways. Commercial traffic had different temporal patterns and greater variability than noncommercial vehicle traffic, e.g., the weekday variability of hourly commercial volume was 28%. The results indicate that TAFs for a metropolitan region can provide reasonably accurate estimates of hourly vehicle volume on major roads. While vehicle volume is only one of many factors that govern on-road emission rates, air quality analyses would be strengthened by incorporating information regarding the uncertainty and variability of traffic activity. PMID:26688671

Presenting SAPUSS: Solving Aerosol Problem by Using Synergistic Strategies in Barcelona, Spain

NASA Astrophysics Data System (ADS)

Dall'Osto, M.; Querol, X.; Alastuey, A.; Minguillon, M. C.; Alier, M.; Amato, F.; Brines, M.; Cusack, M.; Grimalt, J. O.; Karanasiou, A.; Moreno, T.; Pandolfi, M.; Pey, J.; Reche, C.; Ripoll, A.; Tauler, R.; Van Drooge, B. L.; Viana, M.; Harrison, R. M.; Gietl, J.; Beddows, D.; Bloss, W.; O'Dowd, C.; Ceburnis, D.; Martucci, G.; Ng, N. L.; Worsnop, D.; Wenger, J.; Mc Gillicuddy, E.; Sodeau, J.; Healy, R.; Lucarelli, F.; Nava, S.; Jimenez, J. L.; Gomez Moreno, F.; Artinano, B.; Prévôt, A. S. H.; Pfaffenberger, L.; Frey, S.; Wilsenack, F.; Casabona, D.; Jiménez-Guerrero, P.; Gross, D.; Cots, N.

2013-09-01

This paper presents the summary of the key objectives, instrumentation and logistic details, goals, and initial scientific findings of the European Marie Curie Action SAPUSS project carried out in the western Mediterranean Basin (WMB) during September-October in autumn 2010. The key SAPUSS objective is to deduce aerosol source characteristics and to understand the atmospheric processes responsible for their generations and transformations - both horizontally and vertically in the Mediterranean urban environment. In order to achieve so, the unique approach of SAPUSS is the concurrent measurements of aerosols with multiple techniques occurring simultaneously in six monitoring sites around the city of Barcelona (NE Spain): a main road traffic site, two urban background sites, a regional background site and two urban tower sites (150 m and 545 m above sea level, 150 m and 80 m above ground, respectively). SAPUSS allows us to advance our knowledge sensibly of the atmospheric chemistry and physics of the urban Mediterranean environment. This is well achieved only because of both the three dimensional spatial scale and the high sampling time resolution used. During SAPUSS different meteorological regimes were encountered, including warm Saharan, cold Atlantic, wet European and stagnant regional ones. The different meteorology of such regimes is herein described. Additionally, we report the trends of the parameters regulated by air quality purposes (both gaseous and aerosol mass concentrations); and we also compare the six monitoring sites. High levels of traffic-related gaseous pollutants were measured at the urban ground level monitoring sites, whereas layers of tropospheric ozone were recorded at tower levels. Particularly, tower level night-time average ozone concentrations (80 ± 25 μg m-3) were up to double compared to ground level ones. The examination of the vertical profiles clearly shows the predominant influence of NOx on ozone concentrations, and a source of ozone aloft. Analysis of the particulate matter (PM) mass concentrations shows an enhancement of coarse particles (PM2.5-10) at the urban ground level (+64%, average 11.7 μg m-3) but of fine ones (PM1) at urban tower level (+28%, average 14.4 μg m-3). These results show complex dynamics of the size-resolved PM mass at both horizontal and vertical levels of the study area. Preliminary modelling findings reveal an underestimation of the fine accumulation aerosols. In summary, this paper lays the foundation of SAPUSS, an integrated study of relevance to many other similar urban Mediterranean coastal environment sites.

An Urban Diffusion Simulation Model for Carbon Monoxide

ERIC Educational Resources Information Center

Johnson, W. B.; And Others

1973-01-01

A relatively simple Gaussian-type diffusion simulation model for calculating urban carbon (CO) concentrations as a function of local meteorology and the distribution of traffic is described. The model can be used in two ways: in the synoptic mode and in the climatological mode. (Author/BL)

Atmospheric aerosol and gaseous pollutant concentrations in Bucharest area using first datasets from the city AQ monitoring network

NASA Astrophysics Data System (ADS)

Balaceanu, Cristina; Iorga, Gabriela

2010-05-01

City of Bucharest is the largest and most populated (about 2.8 million inhabitants) city in the Romanian Plain and encounters environmental problems and meteorology typical for several cities in southeastern Europe. City environment includes intense emissions arising from traffic (about 1 million cars per day), five thermo-electrical power-generation stations, that use both natural gas and oil derivatives for power generation and domestic heating, and from industrial sources (more than 800 small and medium plants). In the present work we performed an extensive analysis of the air pollution state for the Bucharest area (inside and outside the city) using filter measurement aerosol data PM10 and PM2.5. Data spanning over first year of continuous sampling (2005) were taken from the city Air Quality Monitoring Network, which consists of eight sampling stations: three industrial and two traffic, one EPA urban background, one suburban and one regional station located outside of Bucharest. The objective was to assess the PM10 recorded levels and their degree of compliance with the EU-legislated air quality standards and to provide a statistical investigation of the factors controlling seasonal and spatial variations of PM levels. PM10 relationships with other measured air pollutants (SO2, CO, NOx) and meteorological parameters (temperature, relative humidity, atmospheric pressure, wind velocity and direction) were investigated by statistical analysis. Back trajectory modeling and wind direction frequency distributions were used to identify the origin of the polluted air masses. Contribution of combustion (slopes) and non-combustion (intercepts) sources to PM10 recorded levels was quantified by linear analysis, for two seasonal periods: cold (15 October-14 April) and warm (15 April-14 October). PM10 and PM2.5 concentrations were compared with corresponding values in other European urban areas. Main conclusions are as follows: Traffic and industrial sites contribute to the PM10 urban background with about 86%; relative contribution of urban background to regional background is about 37%; Relatively low inter-sites correlation coefficients and no significant geographic differences between sites, more or less uniform traffic pattern suggests local sources may play an important role; PM10average and median values systematically exceed the limit value of 50 ?g/m3 at traffic and industrial sites; at background sites the PM10 are below 50?g/m3 but are higher that values at similar sites in Europe; CO and SO2 do not put serious problems relative to their limits values as NOx does; NOx shows a temporal variation with higher values during the cold season; All gaseous pollutants contribute to the PM10 levels but a significant inter-annual variation of this contribution seems not to be observed; Pollution level in Bucharest seems to be higher than in other European cities for traffic, industrial and suburban background sites; regional background in the larger area of Bucharest seems to be similar with the suburban background sites in other European sites. Seven pollution episodes were identified, from which only one in the cold season has been attributed to the long-range transport. During this episode PM10 levels varied between 161-205 ?g/m3 for all sites, the dominant wind direction was NE (10.2%), with an average wind speed of 1.6 m/s. This shows that local pollution sources seem to have more impact on AQ than the long-range transport. Data presented here give an overview of the range of air pollution concentrations to expect under typical meteorological and seasonal conditions in the larger area of Bucharest. Acknowledgements: Dr. Ing. Danut Cociorva, Leader of the Air Quality Control Group-NIRD-ICIM Bucharest, is gratefully acknowledged for his permission to analyse the data. The air mass back trajectories were calculated using HYSPLIT transport and dispersion model: www.arl.noaa.gov/ ready.html. Financial support from ÖAD Austria, Programm WTZ, Project No: RO 02/2009 and from ANCS Romania, Programm PN II, Contract No: 304/27.04.2009 is gratefully acknowledged.

Low-Wind and Other Microclimatic Factors in Near-road Black Carbon Variability: A Case Study and Assessment Implications

EPA Science Inventory

Airborne black carbon from urban traffic is a climate forcing agent and has been associated with health risk to near-road populations. In this paper, we describe a case study of black carbon concentration and compositional variability at and near a traffic-laden multi-lane highw...

Resistance and resilience of floating mat fens in interior Alaska following airboat disturbance

Treesearch

Amy Zacheis; Kate Doran

2009-01-01

The floating mat fens of the Tanana Flats in interior Alaska are productive wetlands near the urban center of Fairbanks. Airboat traffic has created a network of trails through the floating vegetation mats. We established protected areas along established trails, which allowed for measurement of plant community resistance to airboat traffic and resilience following...

Association of occupational and substance use factors with burnout among urban transit operators.

PubMed

Cunradi, Carol B; Chen, Meng-Jinn; Lipton, Rob

2009-07-01

Burnout is a special type of prolonged occupational stress that is linked with numerous psychosomatic and psychological sequelae and negative job consequences. The purpose of this study is to estimate the contribution of occupational and substance use factors to burnout among a multiethnic sample of urban transit operators (n = 1231). Survey and medical exam data were obtained from participants in the 1993-1995 San Francisco MUNI Health & Safety Study. Burnout was measured with the Maslach Burnout Inventory emotional exhaustion subscale. Occupational factors included frequency of job problems (e.g., equipment, passengers, and traffic), years driving, full or part-time work status, and ergonomic problems (e.g., adjusting the seat, back support, vibration, and rocking or bouncing of seat). Substance use measures were alcohol consumption and smoking status (i.e., current, former, and never smokers). The results of multivariable linear regression analysis showed that job problems (beta = 0.426, p < 0.001), ergonomic problems (beta = 0.138, p < 0.001), and full-time work status (beta = 0.070, p < 0.01) were associated with burnout. Smoking was not significant, but alcohol consumption was positively associated with burnout (beta = 0.067, p < 0.01). Age was negatively correlated with burnout (beta = -0.106, p < 0.001), which may reflect a healthy worker effect. Because aspects of the psychosocial and physical work environments can be modified, the findings have important implications for the prevention of burnout among municipal transit operators.

Multilane Traffic Flow Modeling Using Cellular Automata Theory

NASA Astrophysics Data System (ADS)

Chechina, Antonina; Churbanova, Natalia; Trapeznikova, Marina

2018-02-01

The paper deals with the mathematical modeling of traffic flows on urban road networks using microscopic approach. The model is based on the cellular automata theory and presents a generalization of the Nagel-Schreckenberg model to a multilane case. The created program package allows to simulate traffic on various types of road fragments (T or X type intersection, strait road elements, etc.) and on road networks that consist of these elements. Besides that, it allows to predict the consequences of various decisions regarding road infrastructure changes, such as: number of lanes increasing/decreasing, putting new traffic lights into operation, building new roads, entrances/exits, road junctions.

Signal optimization in urban transport: A totally asymmetric simple exclusion process with traffic lights.

PubMed

Arita, Chikashi; Foulaadvand, M Ebrahim; Santen, Ludger

2017-03-01

We consider the exclusion process on a ring with time-dependent defective bonds at which the hopping rate periodically switches between zero and one. This system models main roads in city traffics, intersecting with perpendicular streets. We explore basic properties of the system, in particular dependence of the vehicular flow on the parameters of signalization as well as the system size and the car density. We investigate various types of the spatial distribution of the vehicular density, and show existence of a shock profile. We also measure waiting time behind traffic lights, and examine its relationship with the traffic flow.

Signal optimization in urban transport: A totally asymmetric simple exclusion process with traffic lights

NASA Astrophysics Data System (ADS)

Arita, Chikashi; Foulaadvand, M. Ebrahim; Santen, Ludger

2017-03-01

We consider the exclusion process on a ring with time-dependent defective bonds at which the hopping rate periodically switches between zero and one. This system models main roads in city traffics, intersecting with perpendicular streets. We explore basic properties of the system, in particular dependence of the vehicular flow on the parameters of signalization as well as the system size and the car density. We investigate various types of the spatial distribution of the vehicular density, and show existence of a shock profile. We also measure waiting time behind traffic lights, and examine its relationship with the traffic flow.

Climate Change and Developing-Country Cities: Implications For Environmental Health and Equity

PubMed Central

Corvalán, Carlos

2007-01-01

Climate change is an emerging threat to global public health. It is also highly inequitable, as the greatest risks are to the poorest populations, who have contributed least to greenhouse gas (GHG) emissions. The rapid economic development and the concurrent urbanization of poorer countries mean that developing-country cities will be both vulnerable to health hazards from climate change and, simultaneously, an increasing contributor to the problem. We review the specific health vulnerabilities of urban populations in developing countries and highlight the range of large direct health effects of energy policies that are concentrated in urban areas. Common vulnerability factors include coastal location, exposure to the urban heat-island effect, high levels of outdoor and indoor air pollution, high population density, and poor sanitation. There are clear opportunities for simultaneously improving health and cutting GHG emissions most obviously through policies related to transport systems, urban planning, building regulations and household energy supply. These influence some of the largest current global health burdens, including approximately 800,000 annual deaths from ambient urban air pollution, 1.2 million from road-traffic accidents, 1.9 million from physical inactivity, and 1.5 million per year from indoor air pollution. GHG emissions and health protection in developing-country cities are likely to become increasingly prominent in policy development. There is a need for a more active input from the health sector to ensure that development and health policies contribute to a preventive approach to local and global environmental sustainability, urban population health, and health equity. PMID:17393341

Scenario-based carbon footprint inventory tool for urban sustainable development decision support: The Cincinnati Case Study

EPA Science Inventory

Rapid growing of travel demand and transportation activities and co-occurring land use changes have resulted in traffic congestion and negative impacts on the environment, energy consumption and green house gas (GHG) emissions in an urban environment. The challenge lies in quanti...

Modelling component evaporation and composition change of traffic-induced ultrafine particles during travel from street canyon to urban background.

PubMed

Nikolova, Irina; MacKenzie, A Rob; Cai, Xiaoming; Alam, Mohammed S; Harrison, Roy M

2016-07-18

We developed a model (CiTTy-Street-UFP) of traffic-related particle behaviour in a street canyon and in the nearby downwind urban background that accounts for aerosol dynamics and the variable vapour pressure of component organics. The model simulates the evolution and fate of traffic generated multicomponent ultrafine particles (UFP) composed of a non-volatile core and 17 Semi-Volatile Organic Compounds (SVOC, modelled as n-alkane proxies). A two-stage modelling approach is adopted: (1) a steady state simulation inside the street canyon is achieved, in which there exists a balance between traffic emissions, condensation/evaporation, deposition, coagulation and exchange with the air above roof-level; and (2) a continuing simulation of the above-roof air parcel advected to the nearby urban park during which evaporation is dominant. We evaluate the component evaporation and associated composition changes of multicomponent organic particles in realistic atmospheric conditions and compare our results with observations from London (UK) in a street canyon and an urban park. With plausible input conditions and parameter settings, the model can reproduce, with reasonable fidelity, size distributions in central London in 2007. The modelled nucleation-mode peak diameter, which is 23 nm in the steady-state street canyon, decreases to 9 nm in a travel time of just 120 s. All modelled SVOC in the sub-10 nm particle size range have evaporated leaving behind only non-volatile material, whereas modelled particle composition in the Aitken mode contains SVOC between C26H54 and C32H66. No data on particle composition are available in the study used for validation, or elsewhere. Measurements addressing in detail the size resolved composition of the traffic emitted UFP in the atmosphere are a high priority for future research. Such data would improve the representation of these particles in dispersion models and provide the data essential for model validation. Enhanced knowledge of the chemical composition of nucleation-mode particles from diesel engine exhaust is needed to predict both their atmospheric behaviour and their implications for human health.

Evaluation of the public health impacts of traffic congestion: a health risk assessment.

PubMed

Levy, Jonathan I; Buonocore, Jonathan J; von Stackelberg, Katherine

2010-10-27

Traffic congestion is a significant issue in urban areas in the United States and around the world. Previous analyses have estimated the economic costs of congestion, related to fuel and time wasted, but few have quantified the public health impacts or determined how these impacts compare in magnitude to the economic costs. Moreover, the relative magnitudes of economic and public health impacts of congestion would be expected to vary significantly across urban areas, as a function of road infrastructure, population density, and atmospheric conditions influencing pollutant formation, but this variability has not been explored. In this study, we evaluate the public health impacts of ambient exposures to fine particulate matter (PM2.5) concentrations associated with a business-as-usual scenario of predicted traffic congestion. We evaluate 83 individual urban areas using traffic demand models to estimate the degree of congestion in each area from 2000 to 2030. We link traffic volume and speed data with the MOBILE6 model to characterize emissions of PM2.5 and particle precursors attributable to congestion, and we use a source-receptor matrix to evaluate the impact of these emissions on ambient PM2.5 concentrations. Marginal concentration changes are related to a concentration-response function for mortality, with a value of statistical life approach used to monetize the impacts. We estimate that the monetized value of PM2.5-related mortality attributable to congestion in these 83 cities in 2000 was approximately $31 billion (2007 dollars), as compared with a value of time and fuel wasted of $60 billion. In future years, the economic impacts grow (to over $100 billion in 2030) while the public health impacts decrease to $13 billion in 2020 before increasing to $17 billion in 2030, given increasing population and congestion but lower emissions per vehicle. Across cities and years, the public health impacts range from more than an order of magnitude less to in excess of the economic impacts. Our analyses indicate that the public health impacts of congestion may be significant enough in magnitude, at least in some urban areas, to be considered in future evaluations of the benefits of policies to mitigate congestion.

Development of a traffic noise prediction model for an urban environment.

PubMed

Sharma, Asheesh; Bodhe, G L; Schimak, G

2014-01-01

The objective of this study is to develop a traffic noise model under diverse traffic conditions in metropolitan cities. The model has been developed to calculate equivalent traffic noise based on four input variables i.e. equivalent traffic flow (Q e ), equivalent vehicle speed (S e ) and distance (d) and honking (h). The traffic data is collected and statistically analyzed in three different cases for 15-min during morning and evening rush hours. Case I represents congested traffic where equivalent vehicle speed is <30 km/h while case II represents free-flowing traffic where equivalent vehicle speed is >30 km/h and case III represents calm traffic where no honking is recorded. The noise model showed better results than earlier developed noise model for Indian traffic conditions. A comparative assessment between present and earlier developed noise model has also been presented in the study. The model is validated with measured noise levels and the correlation coefficients between measured and predicted noise levels were found to be 0.75, 0.83 and 0.86 for case I, II and III respectively. The noise model performs reasonably well under different traffic conditions and could be implemented for traffic noise prediction at other region as well.

Traffic Congestion Detection System through Connected Vehicles and Big Data

PubMed Central

Cárdenas-Benítez, Néstor; Aquino-Santos, Raúl; Magaña-Espinoza, Pedro; Aguilar-Velazco, José; Edwards-Block, Arthur; Medina Cass, Aldo

2016-01-01

This article discusses the simulation and evaluation of a traffic congestion detection system which combines inter-vehicular communications, fixed roadside infrastructure and infrastructure-to-infrastructure connectivity and big data. The system discussed in this article permits drivers to identify traffic congestion and change their routes accordingly, thus reducing the total emissions of CO2 and decreasing travel time. This system monitors, processes and stores large amounts of data, which can detect traffic congestion in a precise way by means of a series of algorithms that reduces localized vehicular emission by rerouting vehicles. To simulate and evaluate the proposed system, a big data cluster was developed based on Cassandra, which was used in tandem with the OMNeT++ discreet event network simulator, coupled with the SUMO (Simulation of Urban MObility) traffic simulator and the Veins vehicular network framework. The results validate the efficiency of the traffic detection system and its positive impact in detecting, reporting and rerouting traffic when traffic events occur. PMID:27136548

Traffic Congestion Detection System through Connected Vehicles and Big Data.

PubMed

Cárdenas-Benítez, Néstor; Aquino-Santos, Raúl; Magaña-Espinoza, Pedro; Aguilar-Velazco, José; Edwards-Block, Arthur; Medina Cass, Aldo

2016-04-28

This article discusses the simulation and evaluation of a traffic congestion detection system which combines inter-vehicular communications, fixed roadside infrastructure and infrastructure-to-infrastructure connectivity and big data. The system discussed in this article permits drivers to identify traffic congestion and change their routes accordingly, thus reducing the total emissions of CO₂ and decreasing travel time. This system monitors, processes and stores large amounts of data, which can detect traffic congestion in a precise way by means of a series of algorithms that reduces localized vehicular emission by rerouting vehicles. To simulate and evaluate the proposed system, a big data cluster was developed based on Cassandra, which was used in tandem with the OMNeT++ discreet event network simulator, coupled with the SUMO (Simulation of Urban MObility) traffic simulator and the Veins vehicular network framework. The results validate the efficiency of the traffic detection system and its positive impact in detecting, reporting and rerouting traffic when traffic events occur.

Variability of particulate matter concentrations along roads and motorways determined by a moving measurement unit

NASA Astrophysics Data System (ADS)

Weijers, E. P.; Khlystov, A. Y.; Kos, G. P. A.; Erisman, J. W.

The spatial variability of aerosol number and mass along roads was determined in different regions (urban, rural and coastal-marine) of the Netherlands. A condensation particle counter (CPC) and an optical aerosol spectrometer (LAS-X) were installed in a van along with a global positioning system (GPS). Concentrations were measured with high-time resolutions while driving allowing investigations not possible with stationary equipment. In particular, this approach proves to be useful to identify those locations where numbers and mass attain high levels ('hot spots'). In general, concentrations of number and mass of particulate matter increase along with the degree of urbanisation, with number concentration being the more sensitive indicator. The lowest particle numbers and PM 1-concentrations are encountered in a coastal and rural area: <5000 cm -3 and 6 μg m -3, respectively. The presence of sea-salt material along the North-Sea coast enhances PM >1-concentrations compared to inland levels. High-particle numbers are encountered on motorways correlating with traffic intensity; the largest average number concentration is measured on the ring motorway around Amsterdam: about 160 000 cm -3 (traffic intensity 100 000 veh day -1). Peak values occur in tunnels where numbers exceed 10 6 cm -3. Enhanced PM 1 levels (i.e. larger than 9 μg m -3) exist on motorways, major traffic roads and in tunnels. The concentrations of PM >1 appear rather uniformly distributed (below 6 μg m -3 for most observations). On the urban scale, (large) spatial variations in concentration can be explained by varying intensities of traffic and driving patterns. The highest particle numbers are measured while being in traffic congestions or when behind a heavy diesel-driven vehicle (up to 600×10 3 cm -3). Relatively high numbers are observed during the passages of crossings and, at a decreasing rate, on main roads with much traffic, quiet streets and residential areas with limited traffic. The number concentration exhibits a larger variability than mass: the mass concentration on city roads with much traffic is 12% higher than in a residential area at the edge of the same city while the number of particles changes by a factor of two (due to the presence of the ultrafine particles (aerodynamic diameter <100 nm). It is further indicated that people residing at some 100 m downwind a major traffic source are exposed to (still) 40% more particles than those living in the urban background areas.

Urban violence is the biggest cause of fatal work-related accidents in Brazil

PubMed Central

Cordeiro, Ricardo; Luz, Verônica Gronau; Hennington, Élida Azevedo; Martins, Ana Cláudia Alves; Tófoli, Luís Fernando

2017-01-01

ABSTRACT OBJECTIVE To quantify the occurrence of deaths directly associated with urban violence among fatal work-related accidents. METHODS Verbal autopsies were performed with the relatives and coworkers of residents of Campinas, state of São Paulo, Brazil, who died from external causes in 2015. We have also analyzed police reports and reports of the Legal Medical Institute related to these deaths. RESULTS We have identified 82 fatal work-related accidents in Campinas in 2015, of which 25 were murders, 35 were traffic accidents not directly related to work activities, and three were suicides at work. The proportional mortality rate for homicides, traffic accidents, and suicides among fatal work-related accidents was estimated at 30.5%, 42.7%, and 3.7%, respectively. CONCLUSIONS Urban violence accounted for three-fourths of the fatal work-related accidents recorded in the period studied. PMID:29236880

Approaching on Colorimetric Change of Porous Calcareous Rocks Exposed in Urban Environmental Conditions from Iasi - Romania

NASA Astrophysics Data System (ADS)

Pelin, V.; Rusu, O.; Sandu, I.; Vasilache, V.; Gurlui, S.; Sandu, A. V.; Cazacu, M. M.; Sandu, I. G.

2017-06-01

According to the scientific literature, the pollution phenomenon is strongly related by the urban activity from the last decades, with direct effects on the state of conservation of the stone constructions also. This paper presents a preliminary study on the colorimetric evolution of the lithic surfaces exposed under strongly traffic influence from the urban microclimate conditions. The analysed lithic surfaces are similar with the building stone from the structure of an historical monument (from 19th century), such as the Stone Bridge in Iasi-Romania, located in the immediate vicinity of the roadside loop with the same name. The colour change monitoring for the above-mentioned geomaterials aims at anticipating the effects of postponing the decongestion of car traffic and implicitly initiating the assessment of the effects of pollution over this historic monument, which is in an advanced state of deterioration and degradation.

Where Am I? Location Archetype Keyword Extraction from Urban Mobility Patterns

PubMed Central

Kostakos, Vassilis; Juntunen, Tomi; Goncalves, Jorge; Hosio, Simo; Ojala, Timo

2013-01-01

Can online behaviour be used as a proxy for studying urban mobility? The increasing availability of digital mobility traces has provided new insights into collective human behaviour. Mobility datasets have been shown to be an accurate proxy for daily behaviour and social patterns, and behavioural data from Twitter has been used to predict real world phenomena such as cinema ticket sale volumes, stock prices, and disease outbreaks. In this paper we correlate city-scale urban traffic patterns with online search trends to uncover keywords describing the pedestrian traffic location. By analysing a 3-year mobility dataset we show that our approach, called Location Archetype Keyword Extraction (LAKE), is capable of uncovering semantically relevant keywords for describing a location. Our findings demonstrate an overarching relationship between online and offline collective behaviour, and allow for advancing analysis of community-level behaviour by using online search keywords as a practical behaviour proxy. PMID:23704964

Where am I? Location archetype keyword extraction from urban mobility patterns.

PubMed

Kostakos, Vassilis; Juntunen, Tomi; Goncalves, Jorge; Hosio, Simo; Ojala, Timo

2013-01-01

Can online behaviour be used as a proxy for studying urban mobility? The increasing availability of digital mobility traces has provided new insights into collective human behaviour. Mobility datasets have been shown to be an accurate proxy for daily behaviour and social patterns, and behavioural data from Twitter has been used to predict real world phenomena such as cinema ticket sale volumes, stock prices, and disease outbreaks. In this paper we correlate city-scale urban traffic patterns with online search trends to uncover keywords describing the pedestrian traffic location. By analysing a 3-year mobility dataset we show that our approach, called Location Archetype Keyword Extraction (LAKE), is capable of uncovering semantically relevant keywords for describing a location. Our findings demonstrate an overarching relationship between online and offline collective behaviour, and allow for advancing analysis of community-level behaviour by using online search keywords as a practical behaviour proxy.

Integrating stochastic time-dependent travel speed in solution methods for the dynamic dial-a-ride problem.

PubMed

Schilde, M; Doerner, K F; Hartl, R F

2014-10-01

In urban areas, logistic transportation operations often run into problems because travel speeds change, depending on the current traffic situation. If not accounted for, time-dependent and stochastic travel speeds frequently lead to missed time windows and thus poorer service. Especially in the case of passenger transportation, it often leads to excessive passenger ride times as well. Therefore, time-dependent and stochastic influences on travel speeds are relevant for finding feasible and reliable solutions. This study considers the effect of exploiting statistical information available about historical accidents, using stochastic solution approaches for the dynamic dial-a-ride problem (dynamic DARP). The authors propose two pairs of metaheuristic solution approaches, each consisting of a deterministic method (average time-dependent travel speeds for planning) and its corresponding stochastic version (exploiting stochastic information while planning). The results, using test instances with up to 762 requests based on a real-world road network, show that in certain conditions, exploiting stochastic information about travel speeds leads to significant improvements over deterministic approaches.

Distributed learning and multi-objectivity in traffic light control

NASA Astrophysics Data System (ADS)

Brys, Tim; Pham, Tong T.; Taylor, Matthew E.

2014-01-01

Traffic jams and suboptimal traffic flows are ubiquitous in modern societies, and they create enormous economic losses each year. Delays at traffic lights alone account for roughly 10% of all delays in US traffic. As most traffic light scheduling systems currently in use are static, set up by human experts rather than being adaptive, the interest in machine learning approaches to this problem has increased in recent years. Reinforcement learning (RL) approaches are often used in these studies, as they require little pre-existing knowledge about traffic flows. Distributed constraint optimisation approaches (DCOP) have also been shown to be successful, but are limited to cases where the traffic flows are known. The distributed coordination of exploration and exploitation (DCEE) framework was recently proposed to introduce learning in the DCOP framework. In this paper, we present a study of DCEE and RL techniques in a complex simulator, illustrating the particular advantages of each, comparing them against standard isolated traffic actuated signals. We analyse how learning and coordination behave under different traffic conditions, and discuss the multi-objective nature of the problem. Finally we evaluate several alternative reward signals in the best performing approach, some of these taking advantage of the correlation between the problem-inherent objectives to improve performance.

Heavy truck restrictions and air quality implications in São Paulo, Brazil.

PubMed

Pérez-Martínez, Pedro José; de Fátima Andrade, María; de Miranda, Regina Maura

2017-11-01

This study quantified the effects of traffic restrictions on diesel fuel heavy vehicles (HVs) on the air quality of the Bandeirantes corridor using hourly data obtained by continuous monitoring of traffic and air quality at sites located on this avenue. The study addressed the air quality of a city impacted by vehicular emissions and that PM 10 and NO X concentrations are mainly due to diesel burning. Data collection was split into two time periods, a period of no traffic constraint on HVs (Nov 2008 and 2009) and a period of constraint (Nov 2010, 2011 and 2012). We found that pollutants on this corridor, mainly PM 10 and NO X , decreased significantly during the period from 2008 to 2012 (28 and 43%, 15.8 and 86.9 ppb) as a direct consequence of HV traffic restrictions (a 72% reduction). Rebound effects in the form of increased traffic of light vehicles (LVs) during this time had impacts on the concentration levels, explaining the differences between rates of reduction in HV traffic and pollutants. Reductions in the number of trucks resulted in longer travel times and increased traffic congestion as a consequence of the modal shift towards LVs. We found that a 51% decrease in PM 10 (28.8 μg m -3 ) was due to a reduction in HV traffic (vehicle emissions were estimated to be 71% of total sources, 40.1 μg m -3 ). This percentage was partially offset by 10% more PM 10 emissions related to an increase in LV traffic, while other causes, such as climatic conditions, contributed to a 13% increase in PM 10 concentrations. The relationships analyzed in this research served to highlight the need to apply urban transport policies aimed at decreasing pollutant concentrations in São Paulo, especially in heavily congested urban corridors on working days. Copyright © 2017 Elsevier Ltd. All rights reserved.

Microscale traffic simulation and emission estimation in a heavily trafficked roundabout in Madrid (Spain).

PubMed

Quaassdorff, Christina; Borge, Rafael; Pérez, Javier; Lumbreras, Julio; de la Paz, David; de Andrés, Juan Manuel

2016-10-01

This paper presents the evaluation of emissions from vehicle operations in a domain of 300m×300m covering a complex urban roundabout with high traffic density in Madrid. Micro-level simulation was successfully applied to estimate the emissions on a scale of meters. Two programs were used: i) VISSIM to simulate the traffic on the square and to compute velocity-time profiles; and ii) VERSIT+micro through ENVIVER that uses VISSIM outputs to compute the related emissions at vehicle level. Data collection was achieved by a measurement campaign obtaining empirical data of vehicle flows and traffic intensities. Twelve simulations of different traffic situations (scenarios) were conducted, representing different hours from several days in a week and the corresponding NOX and PM10 emissions were estimated. The results show a general reduction on average speeds for higher intensities due to braking-acceleration patterns that contribute to increase the average emission factor and, therefore, the total emissions in the domain, especially on weekdays. The emissions are clearly related to traffic volume, although maximum emission scenario does not correspond to the highest traffic intensity due to congestion and variations in fleet composition throughout the day. These results evidence the potential that local measures aimed at alleviating congestion may have in urban areas to reduce emissions. In general, scenario-averaged emission factors estimated with the VISSIM-VERSIT+micro modelling system fitted well those from the average-speed model COPERT, used as a preliminary validation of the results. The largest deviations between these two models occur in those scenarios with more congestion. The design and resolution of the microscale modelling system allow to reflect the impact of actual traffic conditions on driving patterns and related emissions, making it useful for the design of mitigation measures for specific traffic hot-spots. Copyright © 2016 Elsevier B.V. All rights reserved.

Long-term traffic air and noise pollution in relation to mortality and hospital readmission among myocardial infarction survivors.

PubMed

Tonne, Cathryn; Halonen, Jaana I; Beevers, Sean D; Dajnak, David; Gulliver, John; Kelly, Frank J; Wilkinson, Paul; Anderson, H Ross

2016-01-01

There is relatively little evidence of health effects of long-term exposure to traffic-related pollution in susceptible populations. We investigated whether long-term exposure to traffic air and noise pollution was associated with all-cause mortality or hospital readmission for myocardial infarction (MI) among survivors of hospital admission for MI. Patients from the Myocardial Ischaemia National Audit Project database resident in Greater London (n = 1 8,138) were followed for death or readmission for MI. High spatially-resolved annual average air pollution (11 metrics of primary traffic, regional or urban background) derived from a dispersion model (resolution 20 m × 20 m) and road traffic noise for the years 2003-2010 were used to assign exposure at residence. Hazard ratios (HR, 95% confidence interval (CI)) were estimated using Cox proportional hazards models. Most air pollutants were positively associated with all-cause mortality alone and in combination with hospital readmission. The largest associations with mortality per interquartile range (IQR) increase of pollutant were observed for non-exhaust particulate matter (PM(10)) (HR = 1.05 (95% CI 1.00, 1.10), IQR = 1.1 μg/m(3)); oxidant gases (HR = 1.05 (95% CI 1.00, 1.09), IQR = 3.2 μg/m(3)); and the coarse fraction of PM (HR = 1.05 (95% CI 1.00, 1.10), IQR = 0.9 μg/m(3)). Adjustment for traffic noise only slightly attenuated these associations. The association for a 5 dB increase in road-traffic noise with mortality was HR = 1.02 (95% CI 0.99, 1.06) independent of air pollution. These data support a relationship of primary traffic and regional/urban background air pollution with poor prognosis among MI survivors. Although imprecise, traffic noise appeared to have a modest association with prognosis independent of air pollution. Copyright © 2015 The Authors. Published by Elsevier GmbH.. All rights reserved.

Source appointment of fine particle number and volume concentration during severe haze pollution in Beijing in January 2013.

PubMed

Liu, Zirui; Wang, Yuesi; Hu, Bo; Ji, Dongsheng; Zhang, Junke; Wu, Fangkun; Wan, Xin; Wang, Yonghong

2016-04-01

Extreme haze episodes repeatedly shrouded Beijing during the winter of 2012-2013, causing major environmental and health problems. To better understand these extreme events, particle number size distribution (PNSD) and particle chemical composition (PCC) data collected in an intensive winter campaign in an urban site of Beijing were used to investigate the sources of ambient fine particles. Positive matrix factorization (PMF) analysis resolved a total of eight factors: two traffic factors, combustion factors, secondary aerosol, two accumulation mode aerosol factors, road dust, and long-range transported (LRT) dust. Traffic emissions (54%) and combustion aerosol (27%) were found to be the most important sources for particle number concentration, whereas combustion aerosol (33%) and accumulation mode aerosol (37%) dominated particle volume concentrations. Chemical compositions and sources of fine particles changed dynamically in the haze episodes. An enhanced role of secondary inorganic species was observed in the formation of haze pollution. Regional transport played an important role for high particles, contribution of which was on average up to 24-49% during the haze episodes. Secondary aerosols from urban background presented the largest contributions (45%) for the rapid increase of fine particles in the severest haze episode. In addition, the invasion of LRT dust aerosols further elevated the fine particles during the extreme haze episode. Our results showed a clear impact of regional transport on the local air pollution, suggesting the importance of regional-scale emission control measures in the local air quality management of Beijing.

Catchment scale assessment of risk posed by traffic generated heavy metals and polycyclic aromatic hydrocarbons.

PubMed

Ma, Yukun; McGree, James; Liu, An; Deilami, Kaveh; Egodawatta, Prasanna; Goonetilleke, Ashantha

2017-10-01

Heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) are among the most toxic chemical pollutants present in urban stormwater. Consequently, urban stormwater reuse is constrained due to the human health risk posed by these pollutants. This study developed a scientifically robust approach to assess the risk to human health posed by HMs and PAHs in urban stormwater in order to enhance its reuse. Accordingly, an innovative methodology was created consisting of four stages: quantification of traffic and land use parameters; estimation of pollutant concentrations for model development; risk assessment, and risk map presentation. This methodology will contribute to catchment scale assessment of the risk associated with urban stormwater and for risk mitigation. The risk map developed provides a simple and efficient approach to identify the critical areas within a large catchment. The study also found that heavy molecular weight PAHs (PAHs with 5-6 benzene rings) in urban stormwater pose higher risk to human health compared to light molecular PAHs (PAHs with 2-4 benzene rings). These outcomes will facilitate the development of practical approaches for applying appropriate mitigation measures for the safe management of urban stormwater pollution and for the identification of enhanced reuse opportunities. Copyright © 2017 Elsevier Inc. All rights reserved.

Quantifying road dust resuspension in urban environment by Multilinear Engine: A comparison with PMF2

NASA Astrophysics Data System (ADS)

Amato, F.; Pandolfi, M.; Escrig, A.; Querol, X.; Alastuey, A.; Pey, J.; Perez, N.; Hopke, P. K.

Atmospheric PM pollution from traffic comprises not only direct emissions but also non-exhaust emissions because resuspension of road dust that can produce high human exposure to heavy metals, metalloids, and mineral matter. A key task for establishing mitigation or preventive measures is estimating the contribution of road dust resuspension to the atmospheric PM mixture. Several source apportionment studies, applying receptor modeling at urban background sites, have shown the difficulty in identifying a road dust source separately from other mineral sources or vehicular exhausts. The Multilinear Engine (ME-2) is a computer program that can solve the Positive Matrix Factorization (PMF) problem. ME-2 uses a programming language permitting the solution to be guided toward some possible targets that can be derived from a priori knowledge of sources (chemical profile, ratios, etc.). This feature makes it especially suitable for source apportionment studies where partial knowledge of the sources is available. In the present study ME-2 was applied to data from an urban background site of Barcelona (Spain) to quantify the contribution of road dust resuspension to PM 10 and PM 2.5 concentrations. Given that recently the emission profile of local resuspended road dust was obtained (Amato, F., Pandolfi, M., Viana, M., Querol, X., Alastuey, A., Moreno, T., 2009. Spatial and chemical patterns of PM 10 in road dust deposited in urban environment. Atmospheric Environment 43 (9), 1650-1659), such a priori information was introduced in the model as auxiliary terms of the object function to be minimized by the implementation of the so-called "pulling equations". ME-2 permitted to enhance the basic PMF solution (obtained by PMF2) identifying, beside the seven sources of PMF2, the road dust source which accounted for 6.9 μg m -3 (17%) in PM 10, 2.2 μg m -3 (8%) of PM 2.5 and 0.3 μg m -3 (2%) of PM 1. This reveals that resuspension was responsible of the 37%, 15% and 3% of total traffic emissions respectively in PM 10, PM 2.5 and PM 1. Therefore the overall traffic contribution resulted in 18 μg m -3 (46%) in PM 10, 14 μg m -3 (51%) in PM 2.5 and 8 μg m -3 (48%) in PM 1. In PMF2 this mass explained by road dust resuspension was redistributed among the rest of sources, increasing mostly the mineral, secondary nitrate and aged sea salt contributions.

Distribution and Source Apportionment of Polycyclic Aromatic Hydrocarbons (PAHs) in Forest Soils from Urban to Rural Areas in the Pearl River Delta of Southern China

PubMed Central

Xiao, Yihua; Tong, Fuchun; Kuang, Yuanwen; Chen, Bufeng

2014-01-01

The upper layer of forest soils (0–20 cm depth) were collected from urban, suburban, and rural areas in the Pearl River Delta of Southern China to estimate the distribution and the possible sources of polycyclic aromatic hydrocarbons (PAHs). Total concentrations of PAHs in the forest soils decreased significantly along the urban–suburban–rural gradient, indicating the influence of anthropogenic emissions on the PAH distribution in forest soils. High and low molecular weight PAHs dominated in the urban and rural forest soils, respectively, implying the difference in emission sources between the areas. The values of PAH isomeric diagnostic ratios indicated that forest soil PAHs were mainly originated from traffic emissions, mixed sources and coal/wood combustion in the urban, suburban and rural areas, respectively. Principal component analysis revealed that traffic emissions, coal burning and residential biomass combustion were the three primary contributors to forest soil PAHs in the Pearl River Delta. Long range transportation of PAHs via atmosphere from urban area might also impact the PAHs distribution in the forest soils of rural area. PMID:24599040