Investigation of alternative work zone merging sign configurations.

DOT National Transportation Integrated Search

2013-12-01

This study investigated the effect of an alternative merge sign configuration within a freeway work zone. In this alternative : configuration, the graphical lane closed sign from the MUTCD was compared with a MERGE/arrow sign on one side and a : RIGH...

Utilization of remote traffic monitoring devices for urban freeway work zone assessment.

DOT National Transportation Integrated Search

2012-01-01

The objective of this project was to promote and facilitate analysis and evaluation of the impacts of road construction activities in Smart : Work Zone Deployment Initiative (SWZDI) states. : The two primary objectives of this project were to assess ...

Considerations for the Development of Work Zone Mobility Performance Measures and Thresholds for Virginia Freeways.

DOT National Transportation Integrated Search

2014-02-01

"The Federal Highway Administration has been encouraging states to improve their monitoring and tracking of the : mobility impacts of work zones. The use of mobility performance measures will enable agencies to assess better the : contribution of wor...

Effects of road construction intensity and operations on rural freeway work zone capacity.

DOT National Transportation Integrated Search

2014-11-01

Capacity is affected by construction type and its intensity on adjacent open traffic lanes. The effect on capacity is a function of : vehicles moving in and out of the closed lanes of the work zone, and the presence of heavy construction vehicles. Co...

Public opinion and understanding of advance warning arrow displays used in short-term, mobile, and moving work zones.

DOT National Transportation Integrated Search

2008-03-01

"In long-term work zones on multilane highways and/or freeways, the Federal Highway Administration has interpreted the : Manual on Uniform Traffic Control Devices to mean that only one advance warning arrow displays can be used to denote : the closur...

Safety performance functions for freeway merge zones.

DOT National Transportation Integrated Search

2013-12-01

This report documents the results of a research project to support CDOT in the area of Safety : Performance Function (SPF) development. The project involved collecting data and developing SPFs for : ramp-freeway merge zones categorized as isolated, n...

Evaluation of temporary ramp metering for work zones.

DOT National Transportation Integrated Search

2012-11-01

Ramp metering has been successfully implemented in many states to improve traffic operations on freeways. Studies have documented the positive mobility and safety benefits of ramp metering. However, there have been no studies on the use of ramp meter...

Implementation and testing of the travel time prediction system (TIPS) : final report, May 2001.

DOT National Transportation Integrated Search

2001-05-01

The Travel Time Prediction System (TIPS) is a portable automated system for predicting and displaying travel time for motorists in advance of and through freeway construction work zones, on a real-time basis. It collects real-time traffic flow data u...

Implementation and testing of the travel time prediction system (TIPS) : executive summary, May 2001.

DOT National Transportation Integrated Search

2001-05-01

The Travel Time Prediction System (TIPS) is a portable automated system for predicting and displaying travel time for motorists in advance of and through freeway construction work zones, on a real-time basis. It collects real-time traffic flow data u...

Literature review of methods to determine road user costs in construction zones

DOT National Transportation Integrated Search

1997-01-01

As freeway construction increases with the need to expand, repair and maintain the existing infrastructure, the desire to quantify the inconvenience or delay costs to the user of the freeway undergoing construction has increased and become neccessary...

Seven Experiment Designs Addressing Problems of Safety and Capacity on Two-Lane Rural Highways : Volume 8. Experimental Design and Evaluate Remedial Aids for Intersections with Inadequate Sight Distance

DOT National Transportation Integrated Search

2007-01-01

Americans lose 3.7 billion hours and 2.3 billion gallons of fuel every year sitting in traffic jams, and nearly 24 percent of non-recurring freeway delay, or about 482 million hours, is attributed to work zones. To combat the country's growing transp...

Trees and highway safety.

DOT National Transportation Integrated Search

2011-03-01

To minimize the severity of run-off-road collisions of vehicles with trees, departments of transportation (DOTs) : commonly establish clear zones for trees and other fixed objects. Caltrans clear zone on freeways is 30 feet : minimum (40 feet pref...

Making the Traffic Operations Case for Congestion Pricing: Operational Impacts of Congestion Pricing

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

Chin, Shih-Miao; Hu, Patricia S; Davidson, Diane

2011-02-01

Congestion begins when an excess of vehicles on a segment of roadway at a given time, resulting in speeds that are significantly slower than normal or 'free flow' speeds. Congestion often means stop-and-go traffic. The transition occurs when vehicle density (the number of vehicles per mile in a lane) exceeds a critical level. Once traffic enters a state of congestion, recovery or time to return to a free-flow state is lengthy; and during the recovery process, delay continues to accumulate. The breakdown in speed and flow greatly impedes the efficient operation of the freeway system, resulting in economic, mobility, environmentalmore » and safety problems. Freeways are designed to function as access-controlled highways characterized by uninterrupted traffic flow so references to freeway performance relate primarily to the quality of traffic flow or traffic conditions as experienced by users of the freeway. The maximum flow or capacity of a freeway segment is reached while traffic is moving freely. As a result, freeways are most productive when they carry capacity flows at 60 mph, whereas lower speeds impose freeway delay, resulting in bottlenecks. Bottlenecks may be caused by physical disruptions, such as a reduced number of lanes, a change in grade, or an on-ramp with a short merge lane. This type of bottleneck occurs on a predictable or 'recurrent' basis at the same time of day and same day of week. Recurrent congestion totals 45% of congestion and is primarily from bottlenecks (40%) as well as inadequate signal timing (5%). Nonrecurring bottlenecks result from crashes, work zone disruptions, adverse weather conditions, and special events that create surges in demand and that account for over 55% of experienced congestion. Figure 1.1 shows that nonrecurring congestion is composed of traffic incidents (25%), severe weather (15%), work zones, (10%), and special events (5%). Between 1995 and 2005, the average percentage change in increased peak traveler delay, based on hours spent in traffic in a year, grew by 22% as the national average of hours spent in delay grew from 36 hours to 44 hours. Peak delay per traveler grew one-third in medium-size urban areas over the 10 year period. The traffic engineering community has developed an arsenal of integrated tools to mitigate the impacts of congestion on freeway throughput and performance, including pricing of capacity to manage demand for travel. Congestion pricing is a strategy which dynamically matches demand with available capacity. A congestion price is a user fee equal to the added cost imposed on other travelers as a result of the last traveler's entry into the highway network. The concept is based on the idea that motorists should pay for the additional congestion they create when entering a congested road. The concept calls for fees to vary according to the level of congestion with the price mechanism applied to make travelers more fully aware of the congestion externality they impose on other travelers and the system itself. The operational rationales for the institution of pricing strategies are to improve the efficiency of operations in a corridor and/or to better manage congestion. To this end, the objectives of this project were to: (1) Better understand and quantify the impacts of congestion pricing strategies on traffic operations through the study of actual projects, and (2) Better understand and quantify the impacts of congestion pricing strategies on traffic operations through the use of modeling and other analytical methods. Specifically, the project was to identify credible analytical procedures that FHWA can use to quantify the impacts of various congestion pricing strategies on traffic flow (throughput) and congestion.« less

Shear zone junctions: Of zippers and freeways

NASA Astrophysics Data System (ADS)

Passchier, Cees W.; Platt, John P.

2017-02-01

Ductile shear zones are commonly treated as straight high-strain domains with uniform shear sense and characteristic curved foliation trails, bounded by non-deforming wall rock. Many shear zones, however, are branched, and if movement on such branches is contemporaneous, the resulting shape can be complicated and lead to unusual shear sense arrangement and foliation geometries in the wall rock. For Y-shaped shear zone triple junctions with three joining branches and transport direction at a high angle to the branchline, only eight basic types of junction are thought to be stable and to produce significant displacement. The simplest type, called freeway junctions, have similar shear sense in all three branches. The other types show joining or separating behaviour of shear zone branches similar to the action of a zipper. Such junctions may have shear zone branches that join to form a single branch (closing zipper junction), or a single shear zone that splits to form two branches, (opening zipper junction). All categories of shear zone junctions show characteristic foliation patterns and deflection of markers in the wall rock. Closing zipper junctions are unusual, since they form a non-active zone with opposite deflection of foliations in the wall rock known as an extraction fault or wake. Shear zipper junctions can form domains of overprinting shear sense along their flanks. A small and large field example are given from NE Spain and Eastern Anatolia. The geometry of more complex, 3D shear zone junctions with slip parallel and oblique to the branchline is briefly discussed.

Operations-oriented performance measures for freeway management systems : final report.

DOT National Transportation Integrated Search

2008-12-01

This report describes the second and final year activities of the project titled Using Operations-Oriented Performance Measures to Support Freeway Management Systems. Work activities included developing a prototype system architecture for testi...

Ramp - Metering Algorithms Evaluated within Simplified Conditions

NASA Astrophysics Data System (ADS)

Janota, Aleš; Holečko, Peter; Gregor, Michal; Hruboš, Marián

2017-12-01

Freeway networks reach their limits, since it is usually impossible to increase traffic volumes by indefinitely extending transport infrastructure through adding new traffic lanes. One of the possible solutions is to use advanced intelligent transport systems, particularly ramp metering systems. The paper shows how two particular algorithms of local and traffic-responsive control (Zone, ALINEA) can be adapted to simplified conditions corresponding to Slovak freeways. Both control strategies are modelled and simulated using PTV Vissim software, including the module VisVAP. Presented results demonstrate the properties of both control strategies, which are compared mutually as well as with the initial situation in which no control strategy is applied

Temporary Losses of Highway Capacity and Impacts on Performance: Phase 2

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

Chin, S.M.

2004-11-10

Traffic congestion and its impacts significantly affect the nation's economic performance and the public's quality of life. In most urban areas, travel demand routinely exceeds highway capacity during peak periods. In addition, events such as crashes, vehicle breakdowns, work zones, adverse weather, railroad crossings, large trucks loading/unloading in urban areas, and other factors such as toll collection facilities and sub-optimal signal timing cause temporary capacity losses, often worsening the conditions on already congested highway networks. The impacts of these temporary capacity losses include delay, reduced mobility, and reduced reliability of the highway system. They can also cause drivers to re-routemore » or reschedule trips. Such information is vital to formulating sound public policies for the highway infrastructure and its operation. In response to this need, Oak Ridge National Laboratory, sponsored by the Federal Highway Administration (FHWA), made an initial attempt to provide nationwide estimates of the capacity losses and delay caused by temporary capacity-reducing events (Chin et al. 2002). This study, called the Temporary Loss of Capacity (TLC) study, estimated capacity loss and delay on freeways and principal arterials resulting from fatal and non-fatal crashes, vehicle breakdowns, and adverse weather, including snow, ice, and fog. In addition, it estimated capacity loss and delay caused by sub-optimal signal timing at intersections on principal arterials. It also included rough estimates of capacity loss and delay on Interstates due to highway construction and maintenance work zones. Capacity loss and delay were estimated for calendar year 1999, except for work zone estimates, which were estimated for May 2001 to May 2002 due to data availability limitations. Prior to the first phase of this study, which was completed in May of 2002, no nationwide estimates of temporary losses of highway capacity by type of capacity-reducing event had been made. This report describes the second phase of the TLC study (TLC2). TLC2 improves upon the first study by expanding the scope to include delays from rain, toll collection facilities, railroad crossings, and commercial truck pickup and delivery (PUD) activities in urban areas. It includes estimates of work zone capacity loss and delay for all freeways and principal arterials, rather than for Interstates only. It also includes improved estimates of delays caused by fog, snow, and ice, which are based on data not available during the initial phase of the study. Finally, computational errors involving crash and breakdown delay in the original TLC report are corrected.« less

Application of ERTS imagery in estimating the environmental impact of a freeway through the Knysna area of South Africa

NASA Technical Reports Server (NTRS)

Williamson, D. T.; Gilbertson, B.

1974-01-01

In the coastal areas north-east and south-west of Knysna, South Africa lie natural forests, lakes and lagoons highly regarded by many for their aesthetic and ecological richness. A freeway construction project has given rise to fears of the degradation or destruction of these natural features. The possibility was investigated of using ERTS imagery to estimate the environmental impact of the freeway and found that: (1) All threatened features could readily be identified on the imagery. (2) It was possible within a short time to provide an area estimate of damage to indigenous forest. (3) In several important respects the imagery has advantages over maps and aerial photos for this type of work. (4) The imagery will enable monitoring of the actual environmental impact of the freeway when completed.

Safety evaluation of joint and conventional lane merge configurations for freeway work zones.

PubMed

Ishak, Sherif; Qi, Yan; Rayaprolu, Pradeep

2012-01-01

Inefficient operation of traffic in work zone areas not only leads to an increase in travel time delays, queue length, and fuel consumption but also increases the number of forced merges and roadway accidents. This study evaluated the safety performance of work zones with a conventional lane merge (CLM) configuration in Louisiana. Analysis of variance (ANOVA) was used to compare the crash rates for accidents involving fatalities, injuries, and property damage only (PDO) in each of the following 4 areas: (1) advance warning area, (2) transition area, (3) work area, and (4) termination area. The analysis showed that the advance warning area had higher fatality, injury, and PDO crash rates when compared to the transition area, work area, and termination area. This finding confirmed the need to make improvements in the advance warning area where merging maneuvers take place. Therefore, a new lane merge configuration, called joint lane merge (JLM), was proposed and its safety performance was examined and compared to the conventional lane merge configuration using a microscopic simulation model (VISSIM), which was calibrated with real-world data from an existing work zone on I-55 and used to simulate a total of 25 different scenarios with different levels of demand and traffic composition. Safety performance was evaluated using 2 surrogate measures: uncomfortable decelerations and speed variance. Statistical analysis was conducted to determine whether the differences in safety performance between both configurations were significant. The safety analysis indicated that JLM outperformed CLM in most cases with low to moderate flow rates and that the percentage of trucks did not have a significant impact on the safety performance of either configuration. Though the safety analysis did not clearly indicate which lane merge configuration is safer for the overall work zone area, it was able to identify the possibly associated safety changes within the work zone area under different traffic conditions. Copyright © 2012 Taylor & Francis Group, LLC

Development of a lane change risk index using vehicle trajectory data.

PubMed

Park, Hyunjin; Oh, Cheol; Moon, Jaepil; Kim, Seongho

2018-01-01

Surrogate safety measures (SSMs) have been widely used to evaluate crash potential, which is fundamental for the development of effective safety countermeasures. Unlike existing SSMs, which are mainly focused on the evaluation of longitudinal vehicle maneuvering leading to rear-end crashes, this study proposes a new method for estimating crash risk while a subject vehicle changes lanes, referred to as the lane change risk index (LCRI). A novel feature of the proposed methodology is its incorporation of the amount of exposure time to potential crash and the expected crash severity level by applying a fault tree analysis (FTA) to the evaluation framework. Vehicle interactions between a subject vehicle and adjacent vehicles in the starting lane and the target lane are evaluated in terms of crash potential during lane change. Vehicle trajectory data obtained from a traffic stream, photographed using a drone flown over a freeway segment, is used to investigate the applicability of the proposed methodology. This study compares the characteristics of compulsory and discretionary lane changes observed in a work zone section and a general section of a freeway using the LCRI. It is expected that the outcome of this study will be valuable in evaluating the effectiveness of various traffic operations and control strategies in terms of lane change safety. Copyright © 2017 Elsevier Ltd. All rights reserved.

No more freeways : urban land use-transportation dynamics without freeway capacity expansion

DOT National Transportation Integrated Search

2011-01-01

Observations of the various limitations of freeway capacity expansion have led to a provocative planning and policy question What if we : completely stop building additional freeway capacity. From a theoretical perspective, as a freeway transport...

Measurements of ultrafine particles carrying different number of charges in on- and near-freeway environments

NASA Astrophysics Data System (ADS)

Lee, Eon S.; Xu, Bin; Zhu, Yifang

2012-12-01

This paper presents measurements of electrical charges on ultrafine particles (UFPs) of different electrical mobility diameters (30, 50, 80, and 100 nm) in on- and near-freeway environments. Using a tandem Differential Mobility Analyzer (DMA) system, we first examined the fraction of UFPs carrying different number of charges on two distinctive freeways: a gasoline-vehicle dominated freeway (I-405) and a heavy-duty diesel truck dominated freeway (I-710). The fractions of UFPs of a given size carrying one or more charges were significantly higher on the freeways than in the background. The background UFPs only carried up to two charges but freeway UFPs could have up to three charges. The total fraction of charged particles was higher on the I-710 than I-405 across the studied electrical mobility diameters. Near the I-405 freeway, we observed a strong decay of charged particles on the downwind side of the freeway. We also found fractional decay of the charged particles was faster than total particle number concentrations, but slower than total ion concentrations downwind from the freeway I-405. Among charged particles, the highest decay rate was observed for particles carrying three charges. Near the I-710 freeway, we found strong net positive charges on nucleation mode particles, suggesting that UFPs were not at steady-state charge equilibrium near freeways.

Quantifying the impact of new freeway segments.

DOT National Transportation Integrated Search

2013-05-01

Many freeway users complain that new freeway segments immediately fill up with traffic after they are constructed. This : diminishes the advantages of reduced costs and reduced driving time that would make freeways theoretically superior to : arteria...

Structure of the San Bernardino Basin Along Two Seismic Transects: Rialto-Colton Fault to the San Andreas Fault and Along the I-215 Freeway (I-10 to SR30)

USGS Publications Warehouse

Catchings, R.D.; Rymer, M.J.; Goldman, M.R.; Gandhok, G.; Steedman, C.E.

2008-01-01

In this report, we present seismic data and acquisition parameters for two seismic profiles acquired in the San Bernardino, California area in May and October 2003. We refer to these seismic profiles as the San Bernardino Regional (SBR) and San Bernardino High-Resolution (SBHR) seismic profiles. We present both un-interpreted and interpreted seismic images so that the structure of the area can independently interpreted by others. We explain the rationale for our interpretations within the text of this report, and in addition, we provide a large body of supporting evidence. The SBR seismic profile extended across the San Bernardino Basin approximately N30?E from the town of Colton to the town of Highland. The data were acquired at night when the signal-to-noise ratios were reasonably good, and for the larger shots, seismic energy propagated across the ~20-km-long array. Tomographic velocity data are available to depths of about 4 km, and low-fold reflection data are available to depths in excess of 5 km. The SBR seismic data reveal an asymmetric, fault-bound basin to about 5 km depth. The SBHR seismic profile trended along the I-215 freeway from its intersection with the Santa Ana River to approximately State Road 30 in San Bernardino. Seismic data acquired along the I-215 freeway provide detailed images, with CDP spacing of approximately 2.5 m along an approximately 8.2-km-long profile; shot and geophone spacing was 5 m. For logistical reasons, the high-resolution (SBHR) seismic data were acquired during daylight hours on the shoulder of the I-215 freeway and within 5 to 10 m of high-traffic volumes, resulting in low signal-to-noise ratios. The limited offset at which refracted first-arrivals could be measured along the SBHR seismic profile limited our measurements of tomographic refraction velocities to relatively shallow (< 150 m) depths. The SBHR reflection data reveal a basin with complex structural details within the upper kilometer. The two seismic profiles show internal consistency and consistency with other existing geophysical data. Collectively, the data suggest that the I-215 freeway trends along the faulted edge of a pull-apart basin, within a zone where the principal slip of the San Jacinto Fault is transferred to the San Andreas Fault. Because the I-215 freeway trends at low angles to these flower-structure faults, both primary and numerous secondary faults are apparent between the I-10 exchange and State Road-30, suggesting that much of the 8-km-long segment of the I-215 freeway could experience movement along primary or secondary faults.

Freeway travel speed calculation model based on ETC transaction data.

PubMed

Weng, Jiancheng; Yuan, Rongliang; Wang, Ru; Wang, Chang

2014-01-01

Real-time traffic flow operation condition of freeway gradually becomes the critical information for the freeway users and managers. In fact, electronic toll collection (ETC) transaction data effectively records operational information of vehicles on freeway, which provides a new method to estimate the travel speed of freeway. First, the paper analyzed the structure of ETC transaction data and presented the data preprocess procedure. Then, a dual-level travel speed calculation model was established under different levels of sample sizes. In order to ensure a sufficient sample size, ETC data of different enter-leave toll plazas pairs which contain more than one road segment were used to calculate the travel speed of every road segment. The reduction coefficient α and reliable weight θ for sample vehicle speed were introduced in the model. Finally, the model was verified by the special designed field experiments which were conducted on several freeways in Beijing at different time periods. The experiments results demonstrated that the average relative error was about 6.5% which means that the freeway travel speed could be estimated by the proposed model accurately. The proposed model is helpful to promote the level of the freeway operation monitoring and the freeway management, as well as to provide useful information for the freeway travelers.

Truck monitoring and warning systems for freeway-to-freeway connections

DOT National Transportation Integrated Search

1999-10-01

This research focuses on the development and evaluation of a truck monitoring and warning (TM&W) system for detecting high, long, fast trucks at freeway-to-freeway connections and activating displays to warn the truck drivers of potential hazards as ...

Truck monitoring and warning systems for freeway-to-freeway connections : summary

DOT National Transportation Integrated Search

1999-10-01

This project focuses on the development and evaluation of a truck monitoring and warning (TM&W) system for detecting high, long, fast trucks at freeway-to-freeway connections and activating displays to warn the truck drivers of potential hazards as t...

Freeway management handbook

DOT National Transportation Integrated Search

1997-08-01

This handbook, 1997 Freeway Management Handbook, is an update of the 1983 Freeway Management Handbook and reflects the tremendous developments in computing and communications technology. It also reflects the importance of Integrated Transportation Ma...

Freeway travel-time estimation and forecasting.

DOT National Transportation Integrated Search

2012-09-01

This project presents a microsimulation-based framework for generating short-term forecasts of travel time on freeway corridors. The microsimulation model that is developed (GTsim), replicates freeway capacity drop and relaxation phenomena critical f...

Modeling cooperative driving behavior in freeway merges.

DOT National Transportation Integrated Search

2011-11-01

Merging locations are major sources of freeway bottlenecks and are therefore important for freeway operations analysis. Microscopic simulation tools have been successfully used to analyze merging bottlenecks and to design optimum geometric configurat...

Simulation of three lanes one-way freeway in low visibility weather by possible traffic accidents

NASA Astrophysics Data System (ADS)

Pang, Ming-bao; Zheng, Sha-sha; Cai, Zhang-hui

2015-09-01

The aim of this work is to investigate the traffic impact of low visibility weather on a freeway including the fraction of real vehicle rear-end accidents and road traffic capacity. Based on symmetric two-lane Nagel-Schreckenberg (STNS) model, a cellular automaton model of three-lane freeway mainline with the real occurrence of rear-end accidents in low visibility weather, which considers delayed reaction time and deceleration restriction, was established with access to real-time traffic information of intelligent transportation system (ITS). The characteristics of traffic flow in different visibility weather were discussed via the simulation experiments. The results indicate that incoming flow control (decreasing upstream traffic volume) and inputting variable speed limits (VSL) signal are effective in accident reducing and road actual traffic volume's enhancing. According to different visibility and traffic demand the appropriate control strategies should be adopted in order to not only decrease the probability of vehicle accidents but also avoid congestion.

Emotional Subjects for Composition.

ERIC Educational Resources Information Center

Micciche, Laura R.

Metaphors such as "gypsy academics,""freeway flyers," and "contingent laborers," ascribed by compositionists to their work and its conditions, comment on the low status of composition specialists and teachers in academic hierarchies. Work is the activity around which a profession forms, and, as such, it produces…

Highway Safety Manual applied in Missouri - freeway/software : research summary.

DOT National Transportation Integrated Search

2016-03-01

AASHTOs Highway Safety Manual (HSM) : includes models for freeway segments, speedchange : lanes (transitional area between mainline : and ramps), ramps, and interchange terminals. : These predictive models for freeway : interchanges need to be cal...

Improve FREQ macroscopic freeway analysis model

DOT National Transportation Integrated Search

2008-07-01

The primary objectives of this project have been to provide technical assistance on district freeway analysis projects, enhance the FREQ model based on guidance and suggestions from Caltrans staff members, and offer three freeway analysis workshops f...

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...

Digging West Oakland : what archaeologists found under the Cypress Freeway.

DOT National Transportation Integrated Search

2005-01-01

In 1989, the Loma Prieta earthquake destroyed 1.25 miles of the double-deck Cypress Freeway in Oakland, California. In realigning and rebuilding the freeway, the California Department of Transportation (Caltrans) undertook to identify any important a...

Twin Cities ramp meter evaluation : evaluation plan

DOT National Transportation Integrated Search

2000-09-25

The Minnesota Department of Transportation (Mn/DOT) uses ramp meters to manage freeway access on approximately 210 miles of freeways in the Twin Cities metropolitan area. Mn/DOT first tested ramp meters in 1969 as a method to optimize freeway safety ...

Quantifying incident-induced travel delays on freeways using traffic sensor data

DOT National Transportation Integrated Search

2008-02-01

Traffic congestion is a major operational problem for freeways in Washington State. Recent studies have estimated that more than 50% of freeway congestion is caused by traffic incidents. To help the Washington State Department of Transportation (WSDO...

Quantifying incident-induced travel delays on freeways using traffic sensor data

DOT National Transportation Integrated Search

2008-05-01

Traffic congestion is a major operational problem for freeways in Washington State. Recent studies have estimated that more than 50 percent of freeway congestion is caused by traffic incidents. To help the Washington State Department of Transportatio...

Innovative methods for calculation of freeway travel time using limited data : final report.

DOT National Transportation Integrated Search

2008-01-01

Description: Travel time estimations created by processing of simulated freeway loop detector data using proposed method have been compared with travel times reported from VISSIM model. An improved methodology was proposed to estimate freeway corrido...

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...

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...

Investigation of contributing factors regarding wrong-way driving on freeways.

DOT National Transportation Integrated Search

2012-10-01

In Illinois, there were 217 wrong-way crashes on freeways from 2004 to 2009, resulting in 44 killed and : 248 injured. This research project sought to determine the contributing factors to wrong-way crashes on : freeways and to develop promising, cos...

Analysis of crash characteristics on freeways with depressed medians in Southcentral Alaska.

DOT National Transportation Integrated Search

2017-05-09

The characteristics of crashes on depressed medians of four freeways in Southcentral Alaska were examined under winter conditions. Cross-median crashes (CMC) were dispersed randomly along the freeways analyzed. CMC were 2.5 times likely to cause a se...

0-6811 : reducing lane and shoulder width to permit an additional lane on a freeway.

DOT National Transportation Integrated Search

2015-03-01

This research identified the operational and : safety implications of using reduced lane and : shoulder widths for a variety of freeway : configurations. As demand on Texas freeways : continues to increase, it is important to better : understand the ...

Correlation Analysis of Freeway Traffic Status and Crashes with Nevada Data.

DOT National Transportation Integrated Search

2017-11-11

This project is to study the correlation between freeway traffic status and crash risks with the historical freeway ITS data and related crash data in Nevada. With the comprehensive review of previous research results, the Center for Advanced Transpo...

Adsorption of heavy metal in freeway by asphalt block

NASA Astrophysics Data System (ADS)

Zheng, Chaocheng

2017-08-01

Heavy metals are toxic, persistent, and carcinogenic in freeway. Various techniques are available for the removal of heavy metals from waste water among soils during freeway including ion-exchange, membrane filtration, electrolysis, coagulation, flotation, and adsorption. Among them, bio-sorption processes are widely used for heavy metal and other pollutant removal due to its sustainable, rapid and economic. In this paper, heavy metal removal facilitated by adsorption in plants during freeway was illustrated to provide concise information on exploring the adsorption efficiency.

Evaluation of Geometric Design Needs of Freeway Systems Based on Traffic and Geometric Data

DOT National Transportation Integrated Search

2013-10-20

In Las Vegas, Nevada, the increased traffic competes for the limited spaces available in the freeway system and thus reduces safety performance. This study identified geometric design issues on freeway systems in Las Vegas, Nevada, based on available...

On the measurement and valuation of travel time variability due to incidents on freeways

DOT National Transportation Integrated Search

1999-12-01

Incidents on freeways frequently cause long, unanticipated delays, increasing the economic cost of travel to motorists. This paper provides a simple model for estimating the mean and variance of time lost due to incidents on freeways. It also reviews...

Reducing lane and shoulder width to permit an additional lane on a freeway : technical report.

DOT National Transportation Integrated Search

2015-03-01

This research effort identified the operational and safety implications of using reduced lane and : shoulder widths for a variety of freeway configurations. The research team used speed, crash, and geometric : data for freeways in Dallas, Houston, an...

Integrated database and analysis system for the evaluation of freeway corridors for potential ramp signaling : [summary].

DOT National Transportation Integrated Search

2011-01-01

Ramp signaling is the installation of traffic signals on freeway on-ramps. Studies have shown that in many locations, ramp signaling helped alleviate traffic congestion and improve safety. However, not all freeway locations are suitable for ramp sign...

Proactive assessment of accident risk to improve safety on a system of freeways.

DOT National Transportation Integrated Search

2012-05-01

This report describes the development and evaluation of real-time crash risk-assessment models for four freeway corridors: U.S. Route 101 NB (northbound) and SB (southbound) and Interstate 880 NB and SB. Crash data for these freeway segments for the ...

The Columbus metropolitan freeway management system (CMFMS) effectiveness study : part 2, the after study.

DOT National Transportation Integrated Search

2006-08-01

A Freeway Management System (FMS) employs various tools to manage a freeway to increase throughput and reduce delay : without additional lanes. The FMS acquires data from the roadway and process these data to identify and respond to : problems. If so...

New framework and decision support tool to warrant detour operations during freeway corridor incident management.

DOT National Transportation Integrated Search

2013-05-01

Up to 60% of freeway delays are due to non-recurrent congestion caused by reduced capacity on a freeway section coupled with long incident : durations. In such conditions, if proper detour strategies could be implemented in time, traffic could circum...

The development of local calibration factors - phase II : Maryland freeways and ramps : final report.

DOT National Transportation Integrated Search

2016-11-01

The goal of the study was to develop local calibration factors (LCFs) for Maryland freeways in order to apply the predictive methods of the Highway Safety Manual (HSM) to the state. LCFs were computed for freeway segments, speed-change lanes, and sig...

Development of an Analysis Tool for Evaluation of Marginal Impacts of Freeway Incidents in the Las Vegas Area Using FAST’s Dashboard Freeway Data.

DOT National Transportation Integrated Search

2014-01-21

Incidents are a major source of non-recurring congestion on freeways. In addition to costing millions of dollars in the loss of life, injuries and property damage, traffic incidents also cause additional losses due to the resulting traffic congestion...

Impact of a freeway on the dispersal of ticks and Ixodes ricinus-borne pathogens: forested resting areas may become Lyme disease hotspots.

PubMed

Hornok, Sándor; Mulvihill, Maria; Szőke, Krisztina; Gönczi, Enikő; Sulyok, Kinga M; Gyuranecz, Miklós; Hofmann-Lehmann, Regina

2017-06-01

Man-made barriers are well known for their effects on ecosystems. Habitat fragmentation, for instance, is a recognised consequence of modern-day infrastructure. The aim of the present study was to investigate the diversity and abundance of tick species, as well as the risks of acquiring tick-borne infections in habitats adjacent to a freeway. Therefore, ixodid ticks were collected from the vegetation at two-week intervals (in the main tick season, from March to June) in eight habitats of different types (forest, grove, grassland) along both sides of a freeway. Ixodes ricinus females were molecularly screened for three species of tick-borne bacteria. In the study period, 887 ixodid ticks were collected. These included 704 I. ricinus (79.4%), 51 Dermacentor reticulatus (5.7%), 78 D. marginatus (8.8%), 35 Haemaphysalis inermis (3.9%) and 19 H. concinna (2.1%). There was no significant difference in the abundance of tick species between similar habitats separated by the freeway, except for the absence of Dermacentor spp. on one side. In I. ricinus females, the overall prevalence of Anaplasma phagocytophilum was low, and (in part due to this low rate) did not show significant difference between the two sides of the freeway. Rickettsia helvetica had significantly different overall prevalence between two distant habitats along the same side of the freeway (12.3% vs. 31.4%), but not between habitats on the opposite sides. Borrelia burgdorferi s.l. showed significantly different overall prevalence between habitats both on the same and on the opposite sides of the freeway (8.6-35.9%), and the difference was higher if relevant habitats were also separated by the freeway. Importantly, the prevalence rate of the Lyme disease agent was highest in a forested resting area of the freeway, and was significantly inversely proportional to the prevalence of A. phagocytophilum (taking into account all evaluated habitats), apparently related to deer population density. Prevalence rates of these bacteria also differed significantly on single sampling occasions between: (1) closely situated habitats of different types; (2) distant and either similar or different habitat types; and (3) habitats on the opposite sides of the freeway. In conclusion, the findings of the present study show that a fenced freeway may contribute to differences in tick species diversity and tick-borne pathogen prevalence along its two sides, and this effect is most likely a consequence of its barrier role preventing deer movements.

Treatments to reduce the frequency of freeway exit sign hits.

DOT National Transportation Integrated Search

2011-06-01

Exit gore signs present a significant maintenance challenge for TxDOT. There is concern regarding the safety : of personnel working in gore areas to replace these signs, and the resources necessary for continual : maintenance. The objective of this p...

Investigations of environmental effects on freeway acoustics.

DOT National Transportation Integrated Search

2013-05-01

We present a generalized terrain PE (GTPE) model for sound propagation in non-uniform terrain following the work of Sack and West (1995). Results for simplified terrain cases illustrate the new models capabilities and the effects of terrain in a n...

Field Test of Slow Moving Traffic Alerting System on Freeways in Las Vegas, Nevada : Assessment of the Effectiveness of the Dynamic Message Signs on the Freeways in Las Vegas, Nevada.

DOT National Transportation Integrated Search

2015-10-17

It has been perceived that the travelers do not respond to the incident messages on the dynamic message signs in the Las Vegas area in Nevada. The objective of the study is to evaluate whether dynamic message signs (DMS) in the Las Vegas freeway syst...

Interactive risk analysis on crash injury severity at a mountainous freeway with tunnel groups in China.

PubMed

Huang, Helai; Peng, Yunying; Wang, Jie; Luo, Qizhang; Li, Xiang

2018-02-01

Traffic safety of freeways has attracted major concerns, especially for a mountainous freeway affected by adverse terrain conditions, constrained roadway geometry and complicated driving environments. On the basis of a comprehensive dataset collected from a mountainous freeway with a length of 61km but gathering 12 tunnels, this study seeks to examining the interactive effect of mountainous freeway alignment, driving behaviors, vehicle characteristics and environmental factors on crash severity. A classification and regression tree (CART) model is employed as it can deal with high-order interactions between explanatory variables. Results show that the driving behavior is the most important determinant for injury severity of mountainous freeway crashes, followed by the crash time, grade, curve radius and vehicle type. These variables, interacted with the factors of season and crash location, may largely account for the likelihood of high risk events which may result in severe crashes. Events associated with a notably higher probability of severe crashes include coach drivers involved in improper lane changing and other improper actions, drivers involved in speeding during afternoon or evening, drivers involved in speeding along large curve and straight segment during morning, noon or night, and drivers involved in fatigue while passing along the downgrade. Safety interventions to prevent severe crashes at the mountainous freeway include hierarchical supervision in terms of hazardous driving events, enhanced enforcement for speeding and fatigue driving, deployment of advanced driving assistance systems for fatigue driving warning, and cumulative driving time monitoring for long-distance-travel freight vehicles. Copyright © 2017 Elsevier Ltd. All rights reserved.

Integrated CCTV.

DOT National Transportation Integrated Search

2004-01-01

The Virginia Department of Transportation (VDOT) has invested in extensive closed-circuit television (CCTV) systems to monitor freeways in urban areas. Generally, these devices are installed as part of freeway management systems (Smart Traffic Center...

Freeway ramp management in Pennsylvania.

DOT National Transportation Integrated Search

2011-03-31

This research identified the opportunities to implement ramp management strategies on freeways in Pennsylvania. The research : explored the need to integrate local arterial traffic signal systems with ramp management strategies to reduce the impacts ...

Traffic behavior at freeway bottlenecks.

DOT National Transportation Integrated Search

2014-09-01

This study examines traffic behavior in the vicinity of a freeway bottleneck, revisiting commonly held : assumptions and uncovering systematic biases that likely have distorted empirical studies of bottleneck : formation, capacity drop, and the funda...

Reevaluation of Ramp Design Speed Criteria

DOT National Transportation Integrated Search

1999-12-01

Current freeway entry ramp design speed criteria were evaluated through observations of twenty ramps in four Texas cities. Field observations of ramp and freeway traffic speed-distance relationships were made using videotaping methods. Traffic operat...

Implementation guideline for non-freeway centerline rumble strips.

DOT National Transportation Integrated Search

2015-03-01

This document presents a guideline for the : implementation of non-freeway centerline rumble : strips on high speed rural highways. It includes : recommended practices, according to MDOT : standards, and describes effective strategies and : technique...

Estimation of capacities on Florida freeways.

DOT National Transportation Integrated Search

2014-09-01

Current capacity estimates within Floridas travel time reliability tools rely on the Highway Capacity Manual (HCM 2010) to : estimate capacity under various conditions. Field measurements show that the capacities of Florida freeways are noticeably...

Phase III Autotrack : integrated CCTV.

DOT National Transportation Integrated Search

2005-01-01

The Virginia Department of Transportation (VDOT) has invested in extensive closed circuit television (CCTV) systems to monitor freeways in urban areas. Generally, these devices are installed as part of freeway management systems (Smart Traffic Center...

Evaluation of the impacts of traffic states on crash risks on freeways.

PubMed

Xu, Chengcheng; Liu, Pan; Wang, Wei; Li, Zhibin

2012-07-01

The primary objective of this study is to divide freeway traffic flow into different states, and to evaluate the safety performance associated with each state. Using traffic flow data and crash data collected from a northbound segment of the I-880 freeway in the state of California, United States, K-means clustering analysis was conducted to classify traffic flow into five different states. Conditional logistic regression models using case-controlled data were then developed to study the relationship between crash risks and traffic states. Traffic flow characteristics in each traffic state were compared to identify the underlying phenomena that made certain traffic states more hazardous than others. Crash risk models were also developed for different traffic states to identify how traffic flow characteristics such as speed and speed variance affected crash risks in different traffic states. The findings of this study demonstrate that the operations of freeway traffic can be divided into different states using traffic occupancy measured from nearby loop detector stations, and each traffic state can be assigned with a certain safety level. The impacts of traffic flow parameters on crash risks are different across different traffic flow states. A method based on discriminant analysis was further developed to identify traffic states given real-time freeway traffic flow data. Validation results showed that the method was of reasonably high accuracy for identifying freeway traffic states. Copyright © 2012 Elsevier Ltd. All rights reserved.

Investigating the impact of static roadside advertising on drivers' situation awareness.

PubMed

Young, Kristie L; Stephens, Amanda N; Logan, David B; Lenné, Michael G

2017-04-01

Roadside advertising has the potential to create a crash risk for drivers as it may distract attention from driving at critical times. In an on-road instrumented vehicle study, we examined if and how static advertising billboards affect drivers' situation awareness across different driving environments. Nineteen fully licensed drivers drove an instrumented vehicle around a 38 km urban test route comprising freeway, busy urban retail and arterial road sections. The route contained a number of static billboards. Drivers provided continuous verbal protocols throughout the drive. Results indicated that the structure and content of drivers' situation awareness was not appreciably affected by the billboards in any of the road environments examined. Drivers focused their attention on the billboards when driving demand was low, such as when driving on the freeway with light to moderate traffic, in lower speed zones, or when stationary. However, when drivers were required to perform a manoeuvre or driving demands increased, drivers directed less attention to the billboards and focussed their awareness on the immediate driving task. This suggests that drivers can, at least under some conditions, effectively self-regulate their attention to billboards when required to focus on the immediate traffic or driving situation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Modeling vehicle interior noise exposure dose on freeways: Considering weaving segment designs and engine operation.

PubMed

Li, Qing; Qiao, Fengxiang; Yu, Lei; Shi, Junqing

2018-06-01

Vehicle interior noise functions at the dominant frequencies of 500 Hz below and around 800 Hz, which fall into the bands that may impair hearing. Recent studies demonstrated that freeway commuters are chronically exposed to vehicle interior noise, bearing the risk of hearing impairment. The interior noise evaluation process is mostly conducted in a laboratory environment. The test results and the developed noise models may underestimate or ignore the noise effects from dynamic traffic and road conditions and configuration. However, the interior noise is highly associated with vehicle maneuvering. The vehicle maneuvering on a freeway weaving segment is more complex because of its nature of conflicting areas. This research is intended to explore the risk of the interior noise exposure on freeway weaving segments for freeway commuters and to improve the interior noise estimation by constructing a decision tree learning-based noise exposure dose (NED) model, considering weaving segment designs and engine operation. On-road driving tests were conducted on 12 subjects on State Highway 288 in Houston, Texas. On-board Diagnosis (OBD) II, a smartphone-based roughness app, and a digital sound meter were used to collect vehicle maneuvering and engine information, International Roughness Index, and interior noise levels, respectively. Eleven variables were obtainable from the driving tests, including the length and type of a weaving segment, serving as predictors. The importance of the predictors was estimated by their out-of-bag-permuted predictor delta errors. The hazardous exposure level of the interior noise on weaving segments was quantified to hazard quotient, NED, and daily noise exposure level, respectively. Results showed that the risk of hearing impairment on freeway is acceptable; the interior noise level is the most sensitive to the pavement roughness and is subject to freeway configuration and traffic conditions. The constructed NED model shows high predictive power (R = 0.93, normalized root-mean-square error [NRMSE] < 6.7%). Vehicle interior noise is usually ignored in the public, and its modeling and evaluation are generally conducted in a laboratory environment, regardless of the interior noise effects from dynamic traffic, road conditions, and road configuration. This study quantified the interior exposure dose on freeway weaving segments, which provides freeway commuters with a sense of interior noise exposure risk. In addition, a bagged decision tree-based interior noise exposure dose model was constructed, considering vehicle maneuvering, vehicle engine operational information, pavement roughness, and weaving segment configuration. The constructed model could significantly improve the interior noise estimation for road engineers and vehicle manufactures.

Freeway bottleneck removals : workshop enhancement and technology transfer.

DOT National Transportation Integrated Search

2009-12-01

As transportation improvement projects become increasingly costly and complex and as funding sources are not : keeping pace with needs in highly urbanized areas, it becomes critical that existing freeway systems be finetuned to : maximize capacity...

Ramp meter design manual

DOT National Transportation Integrated Search

2000-01-01

Caltrans is committed to using ramp metering as an effective traffic management strategy to maintain an efficient freeway system and protect the investment made in constructing freeways by keeping them operating at or near capacity. Ramp Metering is ...

Detroit Corridor Evaluation Plan

DOT National Transportation Integrated Search

1998-01-01

THE GOALS OF THIS PROJECT ARE TO (1) MEASURE THE IMPACTS FROM INSTALLING THE EXISTING ITS FACILITIES, (2) DETERMINE WHETHER MOTORISTS' EXHIBIT A BIAS TOWARD FREEWAYS, (3) CALCULATE THE IMPACT OF FREEWAY BIAS, (3) IDENTIFY OPERATIONAL STRATEGIES THAT ...

Highway Safety Manual applied in Missouri - freeway/software.

DOT National Transportation Integrated Search

2016-06-01

AASHTOs Highway Safety Manual (HSM) facilitates the quantitative safety analysis of highway facilities. In a 2014 : supplement, freeway facilities were added to the original HSM manual which allows the modeling of highway : interchanges. This repo...

Freeway geometric design for active traffic management in Europe

DOT National Transportation Integrated Search

2011-03-01

Continued growth in travel on congested urban freeway corridors exceeds the ability of agencies to provide sufficient solutions and alternatives based on traditional roadway expansion and improvement projects. Several countries are implementing manag...

Review of heavy metal bio-remediation in contaminated freeway facilitated by adsorption

NASA Astrophysics Data System (ADS)

Zheng, Chaocheng

2017-08-01

Toxicity around biological systems is a significant issue for environmental health in a long term. Recent biotechnological approaches for bio-remediation of heavy metals in freeway frequently include mineralization, bio-adsorption or even remediation. Thus, adequate restoration in freeway requiring cooperation, integration and assimilation of such biotechnological advances along with traditional and ethical wisdom to unravel the mystery of nature in the emerging field of bio-remediation was reviewed with highlights to better understand problems associated with toxicity of heavy metals and eco-friendly technologies.

Coordinated Freeway and Arterial Operations Handbook

DOT National Transportation Integrated Search

2006-05-01

Managing and operating freeways and adjacent arterials in a proactive and comprehensive manner, from a system user's perspective, is a major step toward operating all modes of the transportation system at maximum efficiency. The focus of this guide i...

Developing freeway and incident management systems using the national ITS architecture

DOT National Transportation Integrated Search

1998-08-01

This is one of a series of documents providing support for deploying Intelligent Transportation Systems (ITS). This series addresses Traffic Signal Control Systems, Freeway and Incident Management Systems, Transit Management Systems, and Traveler Inf...

Trilogy Operational Test

DOT National Transportation Integrated Search

1998-09-29

The Trilogy project was an ITS demonstration of the broadcast of freeway system traveler information to both commercial and commuter drivers over a 25-mile (40.3 km) radius of the Twin : Cities metropolitan area. In this project, real-time freeway sy...

Connected vehicle enabled freeway merge management - field test.

DOT National Transportation Integrated Search

2016-01-01

Freeway congestion is a major problem of the transportation system, resulting in major economic : loss in terms of traffic delays and fuel costs. With connected vehicle (CV) technologies, more : proactive traffic management strategies are possible. T...

Dynamic Centralized and Decentralized Control Systems

DOT National Transportation Integrated Search

1977-09-01

This report develops a systematic method for designing suboptimal decentralized control systems. The method is then applied to the design of a decentralized controller for a freeway-corridor system. A freeway corridor is considered to be a system of ...

Impact of non-freeway rumble strips phase 1.

DOT National Transportation Integrated Search

2012-06-26

In an effort to reduce lane-departure crashes, in 2008 the Michigan Department of Transportation (MDOT) began a : three-year statewide non-freeway rumble strip installation initiative. This initiative called for the installation of : milled centerlin...

Impact Of Rapid Incident Detection On Freeway Accident Fatalities

DOT National Transportation Integrated Search

1996-06-01

Heavily congested urban highways in the United States have spurred the development of Freeway Management Systems (FMS). Among the goals of these systems is the improvement of traffic management and the facilitation of more rapid incident detection an...

Forecasting the clearance time of freeway accidents

DOT National Transportation Integrated Search

2002-01-01

Freeway congestion is a major and costly problem in many U.S. metropolitan areas. From a traveler's perspective, congestion has costs in terms of longer travel times and lost productivity. From the traffic manager's perspective, congestion causes a f...

Feasibility study for a freeway corridor infrastructure health monitoring instrumentation testbed.

DOT National Transportation Integrated Search

2012-08-01

With current and near-term construction activities within the freeway system of Southeast Wisconsin, there is a unique : opportunity to develop a detailed understanding of their in-service performance by implementing a health monitoring : network tha...

Ramp metering : procedure manual.

DOT National Transportation Integrated Search

2002-11-01

Ramp metering is a traffic management tool used to increase the efficiency and safety of the : traffic operations on freeways. It is one of the most cost effective ways of managing traffic flow. : It improves traffic flow on congested freeways and of...

Evaluation of dual-loop data accuracy using video ground truth data

DOT National Transportation Integrated Search

2002-01-01

Washington State Department of Transportation (WSDOT) initiated a : research project entitled Monitoring Freight on Puget Sound Freeways in September : 1999. Dual-loop data from the Seattle area freeway system were selected as the main data : s...

Freeway travel-time estimation and forecasting.

DOT National Transportation Integrated Search

2013-03-01

Real-time traffic information provided by GDOT has proven invaluable for commuters in the : Georgia freeway network. The increasing number of Variable Message Signs, addition of : services such as My-NaviGAtor, NaviGAtor-to-go etc. and the advancemen...

Implementing the Routine Computation and Use of Roadway Performance Measures within WSDOT

DOT National Transportation Integrated Search

2017-08-01

The Washington State Department of Transportation (WSDOT) is one of the nation's leaders in calculating and using reliability statistics for urban freeways. The Department currently uses reliability measures for decision making for urban freeways-whe...

Cellular automata model for use with real freeway data

DOT National Transportation Integrated Search

2002-01-01

The exponential rate of increase in freeway traffic is expanding the need for accurate and : realistic methods to model and predict traffic flow. Traffic modeling and simulation facilitates an : examination of both microscopic and macroscopic views o...

Data-driven freeway performance evaluation framework for project prioritization and decision making.

DOT National Transportation Integrated Search

2017-01-01

This report describes methods that potentially can be incorporated into the performance monitoring and planning processes for freeway performance evaluation and decision making. Reliability analysis was conducted on the selected I-15 corridor by empl...

Data-driven freeway performance evaluation framework for project prioritization and decision making.

DOT National Transportation Integrated Search

2015-03-01

This report describes methods that potentially can be incorporated into the performance monitoring and planning : processes for freeway performance evaluation and decision making. Reliability analysis is conducted on the selected : I-15 corridor by e...

Developing an area-wide system for coordinated ramp meter control.

DOT National Transportation Integrated Search

2008-12-01

Ramp metering has been broadly accepted and deployed as an effective countermeasure : against both recurrent and non-recurrent congestion on freeways. However, many current ramp : metering algorithms tend to improve only freeway travels using local d...

Investigation of solutions to recurring congestion on freeways.

DOT National Transportation Integrated Search

2009-01-01

Persistent daily congestion, which has been increasing in recent years, is commonly experienced for several hours or more during the morning and evening on Virginia's urban freeways. Many of these roadways are at or near capacity, which causes severe...

Bicycle-Friendly Shoulder Rumble Strips

DOT National Transportation Integrated Search

2000-03-01

Shoulder rumble strips have proven to be an effective way to reduce run-off-the-road (ROR) crashes on urban and rural freeways. As the use of shoulder rumble strips is being extended to non-freeway facilities, bicyclists will encounter rumble strips ...

Real time freeway incident detection.

DOT National Transportation Integrated Search

2014-04-01

The US Department of Transportation (US-DOT) estimates that over half of all congestion : events are caused by highway incidents rather than by rush-hour traffic in big cities. Real-time : incident detection on freeways is an important part of any mo...

Access control design on highway interchanges.

DOT National Transportation Integrated Search

2008-01-01

The adequate spacing and design of access to crossroads in the vicinity of freeway ramps are critical to the safety and traffic operations of both the freeway and the crossroad. The research presented in this report develops a methodology to evaluate...

Trilogy : operational test : final report

DOT National Transportation Integrated Search

1998-09-29

The Trilogy project was an ITS demonstration of the broadcast of freeway system traveler information to both commercial and commuter drivers over a 25-mile (40.3 km) radius of the Twin Cities metropolitan area. In this project, real-time freeway syst...

Investigations of environmental effects on freeway acoustics.

DOT National Transportation Integrated Search

2010-03-01

The study reported here was designed to examine the impact of background meteorological conditions on the : propagation of noise from urban freeways in the Phoenix area. The aim was to understand and predict how : sound waves emanating from highways ...

The Initial Nine Space Settlements

NASA Astrophysics Data System (ADS)

Gale, Anita E.; Edwards, Richard P.

2003-01-01

The co-authors describe a chronology of space infrastructure development illustrating how each element of infrastructure enables development of subsequent more ambitious infrastructure. This is likened to the ``Southern California freeway phenomenon'', wherein a new freeway built in a remote area promotes establishment of gas stations, restaurants, hotels, housing, and eventually entire new communities. The chronology includes new launch vehicles, inter-orbit vehicles, multiple LEO space stations, lunar mining, on-orbit manufacturing, tourist destinations, and supporting technologies required to make it all happen. The space settlements encompassed by the chronology are in Earth orbit (L5 and L4), on the lunar surface, in Mars orbit, on the Martian surface, and in the asteroid belt. Each space settlement is justified with a business rationale for construction. This paper is based on materials developed for Space Settlement Design Competitions that enable high school students to experience the technical and management challenges of working on an industry proposal team.

Contribution of highway capital to industry and national productivity growth

DOT National Transportation Integrated Search

1973-10-01

The report contains the authors initial efforts aimed at extending the steady state freeway model for optimizing freeway traffic flow to a non-steady state model. The steady-state model does not allow reaction to continuously changing conditions whic...

Deployment of a tool for measuring freeway safety performance.

DOT National Transportation Integrated Search

2011-12-01

This project updated and deployed a freeway safety performance measurement tool, building upon a previous project that developed the core methodology. The tool evaluates the cumulative risk over time of an accident or a particular kind of accident. T...

Validation of urban freeway models. [supporting datasets

DOT National Transportation Integrated Search

2015-01-01

The goal of the SHRP 2 Project L33 Validation of Urban Freeway Models was to assess and enhance the predictive travel time reliability models developed in the SHRP 2 Project L03, Analytic Procedures for Determining the Impacts of Reliability Mitigati...

Katy Freeway : an evaluation of a second-generation managed lanes project.

DOT National Transportation Integrated Search

2013-04-01

The Katy Freeway Managed Lanes (KML) represents the first operational, multilane managed facility in : Texas and provides an opportunity to benefit from the lessons learned from the project. This study evaluated : multiple aspects of KML and the crit...

Crash location correction for freeway interchange modeling : final report.

DOT National Transportation Integrated Search

2016-06-01

AASHTO released a supplement to the Highway Safety Manual (HSM) in 2014 that includes models for freeway : interchanges composed of segments, speed-change lanes and terminals. A necessary component to the use of HSM is : having the appropriate safety...

Quantifying incident-induced travel delays on freeways using traffic sensor data : phase II

DOT National Transportation Integrated Search

2010-12-01

Traffic incidents cause approximately 50 percent of freeway congestion in metropolitan areas, resulting in extra travel time and fuel cost. Quantifying incident-induced delay (IID) will help people better understand the real costs of incidents, maxim...

Median barrier placement on six-lane, 46-foot median divided freeways

DOT National Transportation Integrated Search

2010-11-01

This report summarizes the research efforts of using finite element modeling and simulations to evaluate the : performance of W-beam guardrails and cable median barriers on six-lane, 46-foot median divided freeways. A : literature review is included ...

Pueblo Freeway Management System (FMS) : final report

DOT National Transportation Integrated Search

2005-05-16

The Pueblo Freeway Management System (FMS) was a FY00 earmarked project. The objective of the project was to enable the Colorado State Patrol (CSP), the City of Pueblo Police Department (PPD), and CDOT (both Region 2 and Colorado Traffic Management C...

Development of incident data collection standards for Virginia Department of Transportation freeway operations.

DOT National Transportation Integrated Search

2005-01-01

The effective management of incidents is necessary in order to maintain efficient freeway operations. Within the Virginia Department of Transportation (VDOT), there are a number of units responsible for supporting incident management. These groups co...

Evaluation of ground mounted diagrammatic entrance ramp approach signs : final report, October 2000.

DOT National Transportation Integrated Search

2000-10-01

Highway-freeway interchanges can be a source of confusion to unfamiliar drivers. Typically, freeway entrance ramp : information is provided by means of trailblazer assemblies (interstate or highway shield, cardinal direction, and a small : white arro...

Criteria for implementing full-width/depth shoulders to accommodate hard shoulder running.

DOT National Transportation Integrated Search

2011-08-22

"WisDOT is considering constructing full-width/depth shoulders along certain freeway segments to carry traffic : during future freeway resurfacing or construction projects. The goal of this measure is to minimize lane closures and : congestion. WisDO...

Modeling hurricane evacuation traffic : evaluation of freeway contraflow evacuation initiation and termination point configurations.

DOT National Transportation Integrated Search

2010-06-01

Over the last five years, the departments of transportation in 12 coastal states threatened by hurricanes have developed plans for the implementation of contraflow traffic operations on freeways during evacuations. Contraflow involves the use of one ...

Use of Intermodal Performance Measures by State Departments of Transportation

DOT National Transportation Integrated Search

1974-01-01

The traffic-density buildup following a lane blockage on a four-lane freeway carrying low-density traffic is determined for several different densities (0.0065, 0.0100, and 0.0106 vehicles per foot) characterizing the freeway. The time for the traffi...

Evaluating outcomes of raising speed limits on high speed non-freeways.

DOT National Transportation Integrated Search

2015-04-01

The purpose of this research was to assist in determining the potential impacts of implementing a : proposed 65 mph speed limit on non-freeways in Michigan. Consideration was given to a broad range of : performance measures, including operating speed...

HSIS Summary Report: Safety Evaluation of Rolled-in Continuous Shoulder Rumble Strips Installed on Freeways

DOT National Transportation Integrated Search

1999-12-01

This study conducted before and after safety evaluations of projects involving the installation of rolled-in continuous shoulder rumble strips (CSRS) on rural and urban freeways. During resurfacing and shoulder rehabilitation projects, rolled-in CSRS...

Implementation elements for conversion of general-purpose freeway lane into high-occupancy-vehicle lane

DOT National Transportation Integrated Search

1997-01-01

Conversion of a general-purpose freeway into a high-occupancy-vehicle (HOV) lane is an alternative to infrastructure addition for HOV system implementation. Research indicates that lane conversion is feasible technically if sufficient HOV usage and m...

Case studies of the access and mobility impact of freeway removal.

DOT National Transportation Integrated Search

2013-01-01

Throughout the United States, there is a growing movement to remove selected sections of : freeways from city centers. Largely seen as a way to restore life and vitality to these areas, this : strategy has the potential for numerous benefits includin...

An evaluation of the Shirley Highway Express-Bus-on-Freeway Demonstration Project.

DOT National Transportation Integrated Search

1973-01-01

The Shirley Highway Express-Bus-on-Freeway Demonstration Project was initiated to test the hypothesis that the provision of rapid and convenient bus service over an exclusive lane would attract significant numbers of automobile passengers. Such a div...

Wrong-way vehicle detection : proof of concept.

DOT National Transportation Integrated Search

2013-03-01

Vehicles that enter freeway exit ramps going the wrong way present one of the most serious traffic hazards on : Arizonas urban freeways. Moler cites a study that finds on average 350 people are killed annually in the United : States as a result of...

Freeway travel time estimation using existing fixed traffic sensors : phase 2.

DOT National Transportation Integrated Search

2015-03-01

Travel time, one of the most important freeway performance metrics, can be easily estimated using the : data collected from fixed traffic sensors, avoiding the need to install additional travel time data collectors. : This project is aimed at fully u...

Freeway travel time estimation using existing fixed traffic sensors : phase 1.

DOT National Transportation Integrated Search

2013-08-01

Freeway travel time is one of the most useful pieces of information for road users and an : important measure of effectiveness (MOE) for traffic engineers and policy makers. In the Greater : St. Louis area, Gateway Guide, the St. Louis Transportation...

Ramp metering : a review of the literature.

DOT National Transportation Integrated Search

1998-01-01

Ramp metering is an effective, viable, and practical strategy used to manage freeway traffic. It is a proven freeway management technique as various forms of ramp control have been in place since the 1960s in the Chicago, Detroit, and Los Angeles are...

Freeway performance measurement system : an operational analysis tool

DOT National Transportation Integrated Search

2001-07-30

PeMS is a freeway performance measurement system for all of California. It processes 2 : GB/day of 30-second loop detector data in real time to produce useful information. Managers : at any time can have a uniform, and comprehensive assessment of fre...

Estimation of traffic recovery time for different flow regimes on freeways.

DOT National Transportation Integrated Search

2008-06-01

This study attempts to estimate post-incident traffic recovery time along a freeway using Monte Carlo simulation techniques. It has been found that there is a linear relationship between post-incident traffic recovery time, and incident time and traf...

Modeling hurricane evacuation traffic : evaluation of freeway contraflow evacuation initiation and termination point configurations.

DOT National Transportation Integrated Search

2006-06-01

Over the last 5 years, the Departments of Transportation in 12 coastal states threatened by hurricanes have developed plans for the implementation of contraflow traffic operations on freeways during evacuations. Contraflow involves the use of one or ...

Efficient determination of vehicle emission factors by fuel use category using on-road measurements: downward trends on Los Angeles freight corridor I-710

PubMed Central

Hudda, N.; Fruin, S.; Delfino, R. J.; Sioutas, C.

2013-01-01

To evaluate the success of vehicle emissions regulations, trends in both fleet-wide average emissions as well as high-emitter emissions are needed, but it is challenging to capture the full spread of vehicle emission factors (EFs) with chassis dynamometer or tunnel studies, and remote sensing studies cannot evaluate particulate compounds. We developed an alternative method that links real-time on-road pollutant measurements from a mobile platform with real-time traffic data, and allows efficient calculation of both the average and the spread of EFs for light-duty gasoline-powered vehicles (LDG) and heavy-duty diesel-powered vehicles (HDD). This is the first study in California to report EFs under a full range of real-world driving conditions on multiple freeways. Fleet average LDG EFs were in agreement with most recent studies and an order of magnitude lower than observed HDD EFs. HDD EFs reflected the relatively rapid decreases in diesel emissions that have recently occurred in Los Angeles/California, and on I-710, a primary route used for goods movement and a focus of additional truck fleet turnover incentives, HDD EFs were often lower than on other freeways. When freeway emission rates (ER) were quantified as the product of EF and vehicle miles traveled (VMT) per time per mile of freeway, despite a twoto three-fold difference in HDD fractions between freeways, ERs were found to be generally similar in magnitude. Higher LDG VMT on low HDD fraction freeways largely offset the difference. Therefore, the conventional assumption that free ways with the highest HDD fractions are significantly worse sources of total emissions in Los Angeles may no longer be true. PMID:24244208

Efficient determination of vehicle emission factors by fuel use category using on-road measurements: downward trends on Los Angeles freight corridor I-710.

PubMed

Hudda, N; Fruin, S; Delfino, R J; Sioutas, C

2013-01-11

To evaluate the success of vehicle emissions regulations, trends in both fleet-wide average emissions as well as high-emitter emissions are needed, but it is challenging to capture the full spread of vehicle emission factors (EFs) with chassis dynamometer or tunnel studies, and remote sensing studies cannot evaluate particulate compounds. We developed an alternative method that links real-time on-road pollutant measurements from a mobile platform with real-time traffic data, and allows efficient calculation of both the average and the spread of EFs for light-duty gasoline-powered vehicles (LDG) and heavy-duty diesel-powered vehicles (HDD). This is the first study in California to report EFs under a full range of real-world driving conditions on multiple freeways. Fleet average LDG EFs were in agreement with most recent studies and an order of magnitude lower than observed HDD EFs. HDD EFs reflected the relatively rapid decreases in diesel emissions that have recently occurred in Los Angeles/California, and on I-710, a primary route used for goods movement and a focus of additional truck fleet turnover incentives, HDD EFs were often lower than on other freeways. When freeway emission rates (ER) were quantified as the product of EF and vehicle miles traveled (VMT) per time per mile of freeway, despite a twoto three-fold difference in HDD fractions between freeways, ERs were found to be generally similar in magnitude. Higher LDG VMT on low HDD fraction freeways largely offset the difference. Therefore, the conventional assumption that free ways with the highest HDD fractions are significantly worse sources of total emissions in Los Angeles may no longer be true.

NOx emissions from Euro IV busses with SCR systems associated with urban, suburban and freeway driving patterns.

PubMed

Fu, Mingliang; Ge, Yunshan; Wang, Xin; Tan, Jianwei; Yu, Linxiao; Liang, Bin

2013-05-01

NOx and particulate matter (PM) emissions from heavy-duty diesel vehicles (HDVs) have become the most important sources of pollutants affecting urban air quality in China. In recent years, a series of emission control strategies and diesel engine polices have been introduced that require advanced emission control technology. China and Europe mostly have used Selective Catalytic Reduction (SCR) with urea to meet the Euro IV diesel engine emission standard. In this study, two Euro IV busses with SCR were tested by using potable emission measurement system (PEMS) to assess NOx emissions associated with urban, suburban and freeway driving patterns. The results indicated that with the SCR system, the urea injection time for the entire driving period increased with higher vehicle speed. For freeway driving, the urea injection time covered 71%-83% of the driving period; the NOx emission factors from freeway driving were lower than those associated with urban and suburban driving. Unfortunately, the NOx emission factors were 2.6-2.8-, 2.3-2.7- and 2.2-2.3-fold higher than the Euro IV standard limits for urban, suburban and freeway driving, respectively; NOx emission factors (in g/km and g/(kW·h)) from the original vehicles (without SCR) were higher than their corresponding vehicles with SCR for suburban and freeway driving. Compared with the IVE model results, the measured NOx emission factors were 1.60-1.16-, 1.77-1.27-, 2.49-2.44-fold higher than the NOx predicted by the IVE model for urban and suburban driving, respectively. Thus, an adjustment of emission factors is needed to improve the estimation of Euro IV vehicle emissions in China. Copyright © 2013 Elsevier B.V. All rights reserved.

Measurements and predictors of on-road ultrafine particle concentrations and associated pollutants in Los Angeles

NASA Astrophysics Data System (ADS)

Fruin, S.; Westerdahl, D.; Sax, T.; Sioutas, C.; Fine, P. M.

Motor vehicles are the dominant source of oxides of nitrogen (NO x), particulate matter (PM), and certain air toxics (e.g., benzene, 1,3-butadiene) in urban areas. On roadways, motor vehicle-related pollutant concentrations are typically many times higher than ambient concentrations. Due to high air exchange rates typical of moving vehicles, this makes time spent in vehicles on roadways a major source of exposure. This paper presents on-road measurements for Los Angeles freeways and arterial roads taken from a zero-emission electric vehicle outfitted with real-time instruments. The objective was to characterize air pollutant concentrations on roadways and identify the factors associated with the highest concentrations. Our analysis demonstrated that on freeways, concentrations of ultrafine particles (UFPs), black carbon, nitric oxide, and PM-bound polycyclic aromatic hydrocarbons (PM-PAH) are generated primarily by diesel-powered vehicles, despite the relatively low fraction (˜6%) of diesel-powered vehicles on Los Angeles freeways. However, UFP concentrations on arterial roads appeared to be driven primarily by proximity to gasoline-powered vehicles undergoing hard accelerations. Concentrations were roughly one-third of those on freeways. By using a multiple regression model for the freeway measurements, we were able to explain 60-70% of the variability in concentrations of UFP, black carbon, nitric oxide, and PM-PAH using measures of diesel truck density and hour of day (as an indicator of wind speed). Freeway concentrations of these pollutants were also well correlated with readily available annual average daily truck counts, potentially allowing improved population exposure estimates for epidemiology studies. Based on these roadway measurements and average driving time, it appears that 33-45% of total UFP exposure for Los Angeles residents occurs due to time spent traveling in vehicles.

Assessment and validation of managed lanes weaving and access guidelines.

DOT National Transportation Integrated Search

2010-06-01

The goal of this project was to establish spacing requirements for access points to managed lanes : with respect to the location of entrance and exit ramps on the general purpose lanes of the freeway. Traffic : entering the freeway destined for the m...

Impact of non-freeway rumble strips phase 1 : appendix III, example of rear end "target" crashes.

DOT National Transportation Integrated Search

2012-06-25

In an effort to reduce lane-departure crashes, in 2008 the Michigan Department of Transportation (MDOT) began a three-year statewide non-freeway rumble strip installation initiative. This initiative called for the installation of milled centerline ru...

Economic and quality of life impacts of route 21 freeway construction : final report, October 2009.

DOT National Transportation Integrated Search

2009-10-01

Opened to traffic in December 2000, the missing section of the Route 21 Freeway in Clifton : and Passaic (Hope Ave. to the Route 46 Interchange) was designed utilizing the equivalent to : the Context Sensitive Solutions (CSS) approach at ...

Investigation of contributing factors regarding wrong-way driving on freeways, phase II.

DOT National Transportation Integrated Search

2015-09-01

In the second phase of this project, two major tasks were completed: (1) organizing a national wrong-way driving : (WWD) summit and (2) developing guidelines for reducing WWD on freeways. The first national WWD summit was : held in Edwardsville, Illi...

Impact of non-freeway rumble strips phase 1 : appendix I, driver behavior data for curve locations.

DOT National Transportation Integrated Search

2012-06-26

In an effort to reduce lane-departure crashes, in 2008 the Michigan Department of Transportation (MDOT) began a three-year statewide non-freeway rumble strip installation initiative. This initiative called for the installation of milled centerline ru...

Characteristics of transitions in freeway traffic : final report, OTREC-RR-10-12 September 2010.

DOT National Transportation Integrated Search

2010-09-01

This research seeks to understand the characteristics of transitions as freeway traffic changes from one state to another. This study addresses the features of two types of transitions; transitions near a merge and transitions along shock waves durin...

Understanding Traveler Behavior : The Psychology Behind Managed Lane Use

DOT National Transportation Integrated Search

2012-07-01

Recent analysis of Katy Freeway/Managed Lane (ML) travelers and I-394 Freeway/High : Occupancy Toll (HOT) lane traveler data has found that many travelers pay to use these HOT : lanes and MLs when adjacent toll-free lanes are operating at nearly the ...

Operational Design Guidelines For High Occupancy Vehicle Lanes On Arterial Roadways, Including Planning Strategies And Supporting Measures

DOT National Transportation Integrated Search

1994-11-01

">THIS REPORT IS A COMPANION TO THE 1993 MINISTRY OF TRANSPORTATION OF ONTARIO DOCUMENT, "OPERATION & DESIGN GUIDELINES FOR HOV LANES ON PROVINCIAL FREEWAYS". SINCE THAT DOCUMENT DEALS EXCLUSIVELY AND COMPREHENSIVELY WITH FREEWAY HOV APPLICATIONS, TH...

Continuous freeway illumination and accidents on a section of Rte. I-95.

DOT National Transportation Integrated Search

1978-01-01

Beginning with the oil embargo of 1973-74, highway lighting and particularly continuous lighting on freeways became one of the first items to be cut back to conserve energy and revenue. During this period of energy shortage, considerable lighting was...

Truck accidents at freeway ramps : data analysis and high-risk site identification

DOT National Transportation Integrated Search

1998-01-01

To examine the relationship of ramp design to truck accident rates, this paper presents an analysis of truck accidents in Washington State, plus a comparison to limited data from Colorado and California. The authors group freeway truck accidents by r...

Simulation-Based Testbed Development for Analyzing Toll Impacts on Freeway Travel

DOT National Transportation Integrated Search

2012-06-01

Traffic congestion has been a world-wide problem in metropolitan areas all over the world. Toll-based traffic management is one of the most applicable solutions against freeway congestion. This research chooses two toll roads, the SR-167 HOT Lane and...

Macroscopic modeling of freeway traffic using an artificial neural network

DOT National Transportation Integrated Search

1997-01-01

Traffic flow on freeways is a complex process that often is described by a set of highly nonlinear, dynamic equations in the form of a macroscopic traffic flow model. However, some of the existing macroscopic models have been found to exhibit instabi...

U.S. National Interests in the Asia-Pacific Region

DTIC Science & Technology

1991-04-22

ADDRESS (City, State, and ZIP Code) 10 SOURCE OF FUNDING NUMBERS PROGRAM PROJECT TASK WORK UNIT ELEMENT NO. NO. NO. ACCESSION %0 11. TITLE (Include...through the work of missionaries while the Asian countries would produce "bolts of cloth", his vision that the traffic would be a two- way affair has...critical freeway which links a number of countries with extreme diversity in history, culture , and economic development. This diversity ranges from an

The nuisance due to the noise of automobile traffic: An investigation in the neighborhoods of freeways

NASA Technical Reports Server (NTRS)

Lamure, C.; Bacelon, M.

1980-01-01

An inquiry was held among 400 people living near freeways in an attempt to determine the characteristics of traffic noise nuisance. A nuisance index was compiled, based on the answers to a questionnaire. Nuisance expressed in these terms was then compared with the noise level measured on the most exposed side of each building. Correlation between the nuisance indexes and the average noise levels is quite good for dwellings with facades parallel to the freeway. At equal noise levels on the most exposed side, the nuisance given for these latter dwellings is lower than for others.

Integrated arterial and freeway operation control strategies for IVHS advanced traffic management systems : research report

DOT National Transportation Integrated Search

1998-09-01

The main focus of this study is congestion, primarily that occurring on freeway corridors in metropolitan areas. Lack of coordination in the operation of various components of the system is often a major source of inefficiency, : resulting in greater...

San Antonio's Medical Center Corridor: Lessons Learned From The Metropolitan Model Deployment Initiative: Reducing Delay Through Integrated Freeway & Arterial Management

DOT National Transportation Integrated Search

2000-10-01

This report demonstrates the benefits and potential pitfalls of deploying and operating an integrated freeway and arterial management system. In particular, it discusses the lessons learned about the Medical Center Corridor (MCC) Project deployed in ...

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...

Integrated database and analysis system for the evaluation of freeway corridors for potential ramp signaling.

DOT National Transportation Integrated Search

2011-11-15

Ramp signaling is a relatively low-cost traffic management strategy that aims to improve the flow of : traffic by controlling the rate at which vehicles enter the freeway. While studies have shown that ramp : signaling helps to alleviate traffic cong...

Guide for Resurfacing, Restoration and Rehabilitation of Highways and Streets (Other than Freeways)

DOT National Transportation Integrated Search

1995-04-01

The primary purpose of R-R-R projects is to provide a better riding surface, enhance safety, : improve operating conditions, and to preserve and extend the service life of existing non-freeway : facilities. Highway safety is an essential element of R...

Proactive assessment of accident risk to improve safety on a system of freeways : [research brief].

DOT National Transportation Integrated Search

2012-05-01

As traffic safety on freeways continues to be a growing concern, much progress has been made in shifting from reactive (incident detection) to proactive (real-time crash risk assessment) traffic strategies. Reliable models that can take in real-time ...

Data mining of tree-based models to analyze freeway accident frequency.

PubMed

Chang, Li-Yen; Chen, Wen-Chieh

2005-01-01

Statistical models, such as Poisson or negative binomial regression models, have been employed to analyze vehicle accident frequency for many years. However, these models have their own model assumptions and pre-defined underlying relationship between dependent and independent variables. If these assumptions are violated, the model could lead to erroneous estimation of accident likelihood. Classification and Regression Tree (CART), one of the most widely applied data mining techniques, has been commonly employed in business administration, industry, and engineering. CART does not require any pre-defined underlying relationship between target (dependent) variable and predictors (independent variables) and has been shown to be a powerful tool, particularly for dealing with prediction and classification problems. This study collected the 2001-2002 accident data of National Freeway 1 in Taiwan. A CART model and a negative binomial regression model were developed to establish the empirical relationship between traffic accidents and highway geometric variables, traffic characteristics, and environmental factors. The CART findings indicated that the average daily traffic volume and precipitation variables were the key determinants for freeway accident frequencies. By comparing the prediction performance between the CART and the negative binomial regression models, this study demonstrates that CART is a good alternative method for analyzing freeway accident frequencies. By comparing the prediction performance between the CART and the negative binomial regression models, this study demonstrates that CART is a good alternative method for analyzing freeway accident frequencies.

A simulation study of the impact of the public-private partnership strategy on the performance of transport infrastructure.

PubMed

Huang, Zhengfeng; Zheng, Pengjun; Ma, Yanqiang; Li, Xuan; Xu, Wenjun; Zhu, Wanlu

2016-01-01

The choice of investment strategy has a great impact on the performance of transport infrastructure. Positive projects such as the "Subway plus Property" model in Hong Kong have created sustainable financial profits for the public transport projects. Owing to a series of public debt and other constraints, public-private partnership (PPP) was introduced as an innovative investment model to address this issue and help develop transport infrastructure. Yet, few studies provide a deeper understanding of relationships between PPP strategy and the performance of such transport projects (particularly the whole transport system). This paper defines the research scope as a regional network of freeway. With a popular PPP model, travel demand prediction method, and relevant parameters as input, agents in a simulation framework can simulate the choice of PPP freeway over time. The simulation framework can be used to analyze the relationship between the PPP strategy and performance of the regional freeway network. This study uses the Freeway Network of Yangtze River Delta (FN-YRD) in China as the context. The results demonstrate the value of using simulation models of complex transportation systems to help decision makers choose the right PPP projects. Such a tool is viewed as particularly important given the ongoing transformation of functions of the Chinese transportation sector, including franchise rights of transport projects, and freeway charging mechanism.

Crash prediction method for freeway facilities with high occupancy vehicle (HOV) and high occupancy toll (HOT) lanes.

DOT National Transportation Integrated Search

2015-07-01

This study developed methods for estimating the expected crash frequency of urban freeway segments : with HOV or HOT lanes. The safety impacts of the type of separation between the managed lanes and : general purpose lanes were examined. Separate mod...

Exploration of the SHRP2 naturalistic driving study data to identify factors related to the selection of freeway ramp design speed.

DOT National Transportation Integrated Search

2017-03-01

This research explored the second Strategic Highway Research Program (SHRP2) Naturalistic Driving Study (NDS) database for the potential to identify freeway entrance and exit ramps and teen drivers behavior while traveling those ramps. This is in ...

Freeway roadside management: the urban forest beyond the white line

Treesearch

Kathleen Wolf

2003-01-01

A national survey was conducted in the United States to learn more about public preferences and perceptions regarding forest and vegetation planning and management in urban freeway roadsides. In response to images depicting a visual continuum of landscape management treatments, drivers most preferred settings having tree plantings that...

Performance of Original and Resurfaced Pavements in the Illinois Freeway System

DOT National Transportation Integrated Search

1997-02-01

In previous studies, the performance of bare and resurfaced JRCP and CRCP on the Illinois freeway system was assessed by survival analyses. In this study, the 1994 data has been used to update the survival analysis of JRCP and CRCP and to carry out a...

What have we learned about intelligent transportation systems? Chapter 2, What have we learned about freeway incident and emergency management and electronic toll collection?

DOT National Transportation Integrated Search

2000-12-01

The intelligent infrastructure is often the most visible manifestation of intelligent transportation systems (ITS) along with roads, freeways, and incident management is often among the first ITS elements implemented. They can significantly contribut...

Impact of non-freeway rumble strips phase 1 : appendix II, example of run off the road left "target" crashes.

DOT National Transportation Integrated Search

2012-06-26

In an effort to reduce lane-departure crashes, in 2008 the Michigan Department of Transportation (MDOT) began a three-year statewide non-freeway rumble strip installation initiative. This initiative called for the installation of milled centerline ru...

Evaluation of road expansion and connectivity mitigation for wildlife in southern California

USGS Publications Warehouse

Alonso, Robert S.; Lyren, Lisa M.; Boydston, Erin E.; Haas, Christopher D.; Crooks, Kevin R.

2014-01-01

We designed a remote-camera survey to study how the expansion of California State Route 71 (CA-71) and implementation of connectivity mitigation affected the use of underpasses by large mammals in southern California. Based on detections by cameras, the use of underpasses by bobcats (Lynx rufus) was higher within the area of expansion and mitigation after construction than before, but there was no difference in use of underpasses in the impact zone compared to the control zone before or after construction. Use of underpasses by coyotes (Canis latrans) was higher in the control zone than in the impact zone, but there was no difference in use before and after construction. Small numbers of detections of mule deer (Odocoileus hemionus) at only a few underpasses precluded comparison between control and impact zones. However, a comparison of use before and after construction revealed that use of underpasses by mule deer was slightly higher post-construction. We cannot fully attribute increased detections post-construction to mitigative efforts, because other factors, such as availability of habitat, urbanization, or demography, also may have influenced use of underpasses along CA-71. Nonetheless, even with the expansion of the freeway and subsequent increase in volume of traffic, mitigative structures along CA-71 did allow for continued movement and, hence, connectivity across the roadway for large mammals.

Transferability and robustness of real-time freeway crash risk assessment.

PubMed

Shew, Cameron; Pande, Anurag; Nuworsoo, Cornelius

2013-09-01

This study examines the data from single loop detectors on northbound (NB) US-101 in San Jose, California to estimate real-time crash risk assessment models. The classification tree and neural network based crash risk assessment models developed with data from NB US-101 are applied to data from the same freeway, as well as to the data from nearby segments of the SB US-101, NB I-880, and SB I-880 corridors. The performance of crash risk assessment models on these nearby segments is the focus of this research. The model applications show that it is in fact possible to use the same model for multiple freeways, as the underlying relationships between traffic data and crash risk remain similar. The framework provided here may be helpful to authorities for freeway segments with newly installed traffic surveillance apparatuses, since the real-time crash risk assessment models from nearby freeways with existing infrastructure would be able to provide a reasonable estimate of crash risk. The robustness of the model output is also assessed by location, time of day, and day of week. The analysis shows that on some locations the models may require further learning due to higher than expected false positive (e.g., the I-680/I-280 interchange on US-101 NB) or false negative rates. The approach for post-processing the results from the model provides ideas to refine the model prior to or during the implementation. Copyright © 2013 National Safety Council and Elsevier Ltd. All rights reserved.

Chapter C. The Loma Prieta, California, Earthquake of October 17, 1989 - Fire, Police, Transportation and Hazardous Materials

USGS Publications Warehouse

Van Anne, Craig; Scawthorn, Charles R.

1994-01-01

The papers in this chapter discuss some of the failures and successes that resulted from the societal response by a multitude of agencies to the Loma Prieta earthquake. Some of the lessons learned were old ones relearned. Other lessons were obvious ones which had gone unnoticed. Still, knowledge gained from past earthquakes spawned planning and mitigation efforts which proved to be successful in limiting the aftermath effects of the Loma Prieta event. At least four major areas of response are presented in this chapter: the Oakland Police Department response to the challenge of controlled access to the Cypress freeway collapse area without inhibiting relief and recovery efforts; search and rescue of the freeway collapse and the monumental crisis management problem that accompanied it; the short- and long-term impact on transbay transportation systems to move a large work force from home to business; and the handling of hazardous material releases throughout the Bay Area.

Did mud contribute to freeway collapse?

NASA Astrophysics Data System (ADS)

Hough, Susan E.; Friberg, Paul A.; Busby, Robert; Field, Edward F.; Jacob, Klaus H.; Borcherdt, Roger D.

At least 41 people were killed October 17 when the upper tier of the Nimitz Freeway in Oakland, Calif., collapsed during the Ms = 7.1 Loma Prieta earthquake. Seismologists studying aftershocks concluded that soil conditions and resulting ground motion amplification were important in the failure of the structure and should be considered in the reconstruction of the highway.Structural design weaknesses in the two-tiered freeway, known as the Cypress structure, had been identified before the tragedy. The seismologists, from Lamont Doherty Geological Observatory in Palisades, N.Y., and the U.S. Geological Survey in Menlo Park, Calif., found that the collapsed section was built on fill over Bay mud. A southern section of the Cypress structure built on alluvium of Quaternary age did not collapse (see Figure 1).

Learning in the Fast Lane: The Freeway Game

ERIC Educational Resources Information Center

Giraud-Carrier, François C.; Schmidt, Glen M.

2015-01-01

When deciding whether to get on the freeway during rush hour, did you ever stop to consider that if you did so, you would slow everybody ELSE down? When we ask our students that question, they typically laugh--their only consideration is how long their own trip will take. When a decision maker does not account for all the costs or benefits…

Wide area detection system: Conceptual design study. [using television and microelectronic technology

NASA Technical Reports Server (NTRS)

Hilbert, E. E.; Carl, C.; Goss, W.; Hansen, G. R.; Olsasky, M. J.; Johnston, A. R.

1978-01-01

An integrated sensor for traffic surveillance on mainline sections of urban freeways is described. Applicable imaging and processor technology is surveyed and the functional requirements for the sensors and the conceptual design of the breadboard sensors are given. Parameters measured by the sensors include lane density, speed, and volume. The freeway image is also used for incident diagnosis.

Dallas Freeway/HOV system planning study: Year 2015. A summary of recommended hov improvements. Interim research report, September 1992-August 1993

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

Walters, C.H.; Lomax, T.J.; Poe, C.M.

1995-07-01

The Dallas Freeway/High-Occupany Vehicle Lane System Planning Study is a joint project in cooperation with the Texas Department of Transportation (TxDOT), Dallas Area Rapid Transit (DART), the North Central Texas Council of Governments (NCTCOG), and the Texas Transportation Institute (TTI). The intent of this effort is to assist in the development of an area-wide freeway/HOV system that recognizes implementation constraints (right-of-way and construction costs) and provides reasonable peak-hour operating conditions on all freeway facilities, while incorporating the long-range plans developed by TxDOT, DART, and NCTCOG. The proposed system is a set of recommendations to be considered and evaluated as partmore » of the development of the NCTCOG Mobility 2010 Plan Update, the long-range transportation plan for the Dallas area. HOV facilities are a significant part of the recommended system in the Dallas System Planning Study, and their implementation is important to the successful operation of the Dallas area transportation system in the future. The report, therefore, focuses on the recommended HOV improvements from the methodology.« less

Analysis of factors associated with traffic injury severity on rural roads in Iran.

PubMed

Kashani, Ali Tavakoli; Shariat-Mohaymany, Afshin; Ranjbari, Andishe

2012-01-01

Iran is a country with one of the highest rates of traffic crash fatality and injury, and seventy percent of these fatalities happen on rural roads. The objective of this study is to identify the significant factors influencing injury severity among drivers involved in crashes on two kinds of major rural roads in Iran: two-lane, two-way roads and freeways. According to the dataset, 213569 drivers were involved in rural road crashes in Iran, over the 3 years from 2006 to 2008. The Classification And Regression Tree method (CART) was applied for 13 independent variables, and one target variable of injury severity with 3 classes of no-injury, injury and fatality. Some of the independent variables were cause of crash, collision type, weather conditions, road surface conditions, driver's age and gender and seat belt usage. The CART model was trained by 70% of these data, and tested with the rest. It was indicated that seat belt use is the most important safety factor for two-lane, two-way rural roads, but on freeways, the importance of this variable is less. Cause of crash, also turned out to be the next most important variable. The results showed that for two-lane, two-way rural roads, "improper overtaking" and "speeding", and for rural freeways, "inattention to traffic ahead", "vehicle defect", and "movement of pedestrians, livestock and unauthorized vehicles on freeways" are the most serious causes of increasing injury severity. The analysis results revealed seat belt use, cause of crash and collision type as the most important variables influencing the injury severity of traffic crashes. To deal with these problems, intensifying police enforcement by means of mobile patrol vehicles, constructing overtaking lanes where necessary, and prohibiting the crossing of pedestrians and livestock and the driving of unauthorized vehicles on freeways are necessary. Moreover, creating a rumble strip on the two edges of roads, and paying attention to the design consistency of roads can be a helpful factor in order to prevent events such as "overturning" and improve the overall safety of freeways.

Driver distraction in an unusual environment: Effects of text-messaging in tunnels.

PubMed

Rudin-Brown, Christina M; Young, Kristie L; Patten, Christopher; Lenné, Michael G; Ceci, Ruggero

2013-01-01

Text messaging while driving can be distracting and significantly increases the risk of being involved in a collision. Compared to freeway driving, driving in a tunnel environment introduces factors that may interact with driver attentional resources to exacerbate the effects of distraction on driving safety. With planning and design of the 18km Stockholm Bypass tunnel ongoing, and because of the potentially devastating consequences of crashes in long tunnels, it is critical to assess the effects of driver distraction in a tunnel environment. Twenty-four participants (25-50 years) drove in simulated highway and tunnel road environments while reading and writing text messages using their own mobile phones. As expected, compared to driving alone, text messaging was associated with decrements in driving performance and visual scanning behavior, and increases in subjective workload. Speeds were slower compared to baseline (no text-messaging) driving when participants performed the text-messaging tasks in the tunnel environment compared to the freeway, suggesting that drivers may have attempted to compensate more for the increased text-messaging-related workload when they were in the tunnel. On the other hand, increases in lane deviation associated with the most complex text-messaging task were more pronounced in the tunnel compared to on the freeway. Collectively, results imply that driver distraction in tunnels is associated with generally similar driving decrements as freeway driving; however, the potential consequences of these decrements in tunnels remain significantly more serious. Future research should attempt to elucidate the nature of any differential compensatory behavior in tunnel, compared to freeway, driving. In the meantime, drivers should be advised to refrain from text messaging, especially when driving in tunnels. Copyright © 2012 Elsevier Ltd. All rights reserved.

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.

Longitudinal safety evaluation of electric vehicles with the partial wireless charging lane on freeways.

PubMed

Li, Ye; Wang, Wei; Xing, Lu; Fan, Qi; Wang, Hao

2018-02-01

As an environment friendly transportation mode, the electric vehicle (EV) has drawn an increasing amount of attention from governments, vehicle manufactories and researchers recently. One of the biggest issue impeding EV's popularization associates with the charging process. The wireless charging lane (WCL) has been proposed as a convenient charging facility for EVs. Due to the high costs, the application of WCL on the entire freeways is impractical in the near future, while the partial WCL (PWCL) may be a feasible solution. This study aims to evaluate longitudinal safety of EVs with PWCL on freeways based on simulations. The simulation experiments are firstly designed, including deployment of PWCL on freeways and distribution of state of charge (SOC) of EVs. Then, a vehicle behavior model for EVs is proposed based on the intelligent driver model (IDM). Two surrogate safety measures, derived from time-to-collision (TTC), are utilized as indicators for safety evaluations. Sensitivity analysis is also conducted for related factors. Results show that the distribution of EVs' SOC significantly affect longitudinal safety when the PWCL is utilized. The low SOC in traffic consisting of EVs has the negative effect on longitudinal safety. The randomness and incompliance of EV drivers worsens the safety performance. The sensitivity analysis indicates that the larger maximum deceleration rate results in the higher longitudinal crash risks of EVs, while the length of PWCL has no monotonous effect. Different TTC thresholds also show no impact on results. A case study shows the consistent results. Based on the findings, several suggestions are discussed for EVs' safety improvement. Results of this study provide useful information for freeway safety when EVs are applied in the future. Copyright © 2017 Elsevier Ltd. All rights reserved.

Field evaluation of vegetation and noise barriers for mitigation of near-freeway air pollution under variable wind conditions

NASA Astrophysics Data System (ADS)

Lee, Eon S.; Ranasinghe, Dilhara R.; Ahangar, Faraz Enayati; Amini, Seyedmorteza; Mara, Steven; Choi, Wonsik; Paulson, Suzanne; Zhu, Yifang

2018-02-01

Traffic-related air pollutants are a significant public health concern, particularly near freeways. Previous studies have suggested either soundwall or vegetation barriers might reduce the near-freeway air pollution. This study aims to investigate the effectiveness of a combination of both soundwall and vegetation barrier for reducing ultrafine particles (UFPs, diameter ≤ 100 nm) and PM2.5 (diameter ≤ 2.5 μm) concentrations. Concurrent data collection was carried out at both upwind and downwind fixed locations approximately 10-15 m away from the edge of two major freeways in California. This study observed that the reduction of UFP and PM2.5 was generally greater with the combination barrier than with either soundwall or vegetation alone. Since there were no non-barrier sites at the study locations, the reductions reported here are all in relative terms. The soundwall barrier was more effective for reducing PM2.5 (25-53%) than UFPs (0-5%), and was most effective (51-53% for PM2.5) when the wind speed ranged between 1 and 2 m/s. Under the same range of wind speed, the vegetation barrier had little effect (0-5%) on reducing PM2.5; but was effective at reducing UFP (up to 50%). For both types of roadside barrier, decreasing wind speed resulted in greater net reduction of UFPs (i.e., total number particle concentrations; inversely proportional). This trend was observed, however, only within specific particle size ranges (i.e., diameter < 20 nm for the soundwall barrier and 12-60 nm for the vegetation barrier). Out of these size ranges, the reduction of UFP concentration was proportional to increasing wind speed. Overall findings of this study support positive effects of soundwall and vegetation barriers for near-freeway air pollution mitigation.

Living near a Freeway is Associated with Lower Bone Mineral Density among Mexican Americans

PubMed Central

Chen, Zhanghua; Salam, Muhammad T.; Karim, Roksana; Toledo-Corral, Claudia M.; Watanabe, Richard M.; Xiang, Anny H.; Buchanan, Thomas A.; Habre, Rima; Bastain, Theresa M.; Lurmann, Fred; Taher, Maryam; Wilson, John P.; Trigo, Enrique; Gilliland, Frank D.

2015-01-01

Purpose Adults residing in rural areas have been linked with higher bone mineral density (BMD). We aimed to determine if this difference is due in part to air pollution by examining the relationships between traffic metrics and ambient air pollution with total body and pelvic BMD. Methods Mexican-American adults (n=1,175; mean 34 years; 72% female) who had participated in the BetaGene study of air pollution, obesity and insulin resistance were included in this analysis. Total body and pelvic BMD were estimated using dual-energy X-ray absorptiometry. Traffic and ambient air pollutant exposures were estimated at residences using location and ambient monitoring data. Variance component models were used to analyze the associations between residential distance to the nearest freeway and ambient air pollutants with BMD. Results Residential proximity to a freeway was associated with lower total body BMD (p-trend=0.01) and pelvic BMD (p-trend=0.03) after adjustment for age, sex, weight and height. The adjusted mean total body and pelvic BMD in participants living within 500m of a freeway were 0.02 g/cm2 and 0.03 g/cm2 lower than participants living greater than 1,500m from a freeway. These associations did not differ significantly by age, sex or obesity status. Results were similar after further adjustment for body fat and weekly physical activity minutes. Ambient air pollutants (NO2, O3 and PM2.5) were not significantly associated with BMD. Conclusions Traffic-related exposures in overweight and obese Mexican-Americans may adversely affect BMD. Our findings indicate that long-term exposures to traffic may contribute to the occurrence of osteoporosis and its consequences. PMID:25677718

Dynamic analysis of a long span, cable-stayed freeway bridge using NASTRAN

NASA Technical Reports Server (NTRS)

Salus, W. L.; Jones, R. E.; Ice, M. W.

1973-01-01

The dynamic analysis for earthquake- and wind-induced response of a long span, cable-stayed freeway bridge by NASTRAN in conjunction with post-processors is described. Details of the structural modeling, the input data generation, and numerical results are given. The influence of the dynamic analysis on the bridge design is traced from the project initiation to the development of a successful earthquake and wind resistant configuration.

Model Development for Risk Assessment of Driving on Freeway under Rainy Weather Conditions

PubMed Central

Cai, Xiaonan; Wang, Chen; Chen, Shengdi; Lu, Jian

2016-01-01

Rainy weather conditions could result in significantly negative impacts on driving on freeways. However, due to lack of enough historical data and monitoring facilities, many regions are not able to establish reliable risk assessment models to identify such impacts. Given the situation, this paper provides an alternative solution where the procedure of risk assessment is developed based on drivers’ subjective questionnaire and its performance is validated by using actual crash data. First, an ordered logit model was developed, based on questionnaire data collected from Freeway G15 in China, to estimate the relationship between drivers’ perceived risk and factors, including vehicle type, rain intensity, traffic volume, and location. Then, weighted driving risk for different conditions was obtained by the model, and further divided into four levels of early warning (specified by colors) using a rank order cluster analysis. After that, a risk matrix was established to determine which warning color should be disseminated to drivers, given a specific condition. Finally, to validate the proposed procedure, actual crash data from Freeway G15 were compared with the safety prediction based on the risk matrix. The results show that the risk matrix obtained in the study is able to predict driving risk consistent with actual safety implications, under rainy weather conditions. PMID:26894434

The Santa Monica freeway diamond lanes. Volume I. Summary. Final report, March 1976-August 1976

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

Billheimer, J.W.; Bullemer, R.J.; Fratessa, C.

1977-09-01

The Santa Monica Freeway Diamond Lanes, a pair of concurrent-flow preferential lanes for buses and carpools linking the City of Santa Monica, California, with the Los Angeles CBD, opened on March 16, 1976 and operated amid much controversy for 21 weeks until the U.S. District Court halted the project. The Diamond Lane project marked the first time preferential lanes had been created by taking busy freeway lanes out of existing service and dedicating them to the exclusive use of high-occupancy vehicles. This report summarizes the findings of the evaluation of the project. The report addresses a broad range of impactsmore » in the following major areas: Traffic speeds and travel times; traffic volumes and carpool information; bus operations and ridership; safety and enforcement; energy and air quality; and public attitudes and response. Analysis shows that the project succeeded in increasing carpool ridership by 65% and the increased bus service accompanying the Diamond Lanes caused bus ridership to more than triple. Nonetheless, energy savings and air quality improvements were insignificant, freeway accidents increased significantly, non-carpoolers lost far more time than carpoolers gained, and a heated public outcry developed which has delayed the implementation of other preferential treatment projects in S. California.« less

Particle concentration and Characteristics near a major freeway with heavy-duty diesel traffic.

PubMed

Ntziachristos, Leonidas; Ning, Zhi; Geller, Michael D; Sioutas, Constantinos

2007-04-01

This study presents the number, surface and volume concentrations, and size distribution of particles next to the 1-710 freeway during February through April 2006. 1-710 has the highest ratio (up to 25%) of heavy-duty diesel vehicles in the Los Angeles highway network. Particle concentration measurements were accompanied by measurements of black carbon, elemental and organic carbon, and gaseous species (CO, CO2). Using the incremental increase of CO2 over the background to calculate the dilution ratio, this study makes it possible to compare particle concentrations measured next to the freeway to concentrations measured in roadway tunnels and in vehicle exhaust. In addition to the effect of the dilution ratio on the measured particle concentrations, multivariate linear regressions showed that light and heavy organic carbon concentrations are positively correlated with the particle volume in the nucleation and accumulation modes, respectively. Solar radiation was also positively correlated with the particle surface concentration and the particle volume in the accumulation (40-638 nm) mode, presumably as a result of secondary particle formation. The methods developed in this study may be used to decouple the effect of sampling position, meteorology, and fleet operation on particle concentrations in the proximity of freeways, roadway tunnels, and in street canyons.

Evaluation of the Scottsdale Loop 101 automated speed enforcement demonstration program.

PubMed

Shin, Kangwon; Washington, Simon P; van Schalkwyk, Ida

2009-05-01

Speeding is recognized as a major contributing factor in traffic crashes. In order to reduce speed-related crashes, the city of Scottsdale, Arizona implemented the first fixed-camera photo speed enforcement program (SEP) on a limited access freeway in the US. The 9-month demonstration program spanning from January 2006 to October 2006 was implemented on a 6.5 mile urban freeway segment of Arizona State Route 101 running through Scottsdale. This paper presents the results of a comprehensive analysis of the impact of the SEP on speeding behavior, crashes, and the economic impact of crashes. The impact on speeding behavior was estimated using generalized least square estimation, in which the observed speeds and the speeding frequencies during the program period were compared to those during other periods. The impact of the SEP on crashes was estimated using 3 evaluation methods: a before-and-after (BA) analysis using a comparison group, a BA analysis with traffic flow correction, and an empirical Bayes BA analysis with time-variant safety. The analysis results reveal that speeding detection frequencies (speeds> or =76 mph) increased by a factor of 10.5 after the SEP was (temporarily) terminated. Average speeds in the enforcement zone were reduced by about 9 mph when the SEP was implemented, after accounting for the influence of traffic flow. All crash types were reduced except rear-end crashes, although the estimated magnitude of impact varies across estimation methods (and their corresponding assumptions). When considering Arizona-specific crash related injury costs, the SEP is estimated to yield about $17 million in annual safety benefits.

Temporary Losses of Highway Capacity and Impacts on Performance

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

Chin, S.M.

2002-07-31

Traffic congestion and its impacts significantly affect the nation's economic performance and the public's quality of life. In most urban areas, travel demand routinely exceeds highway capacity during peak periods. In addition, events such as crashes, vehicle breakdowns, work zones, adverse weather, and suboptimal signal timing cause temporary capacity losses, often worsening the conditions on already congested highway networks. The impacts of these temporary capacity losses include delay, reduced mobility, and reduced reliability of the highway system. They can also cause drivers to re-route or reschedule trips. Prior to this study, no nationwide estimates of temporary losses of highway capacitymore » had been made by type of capacity-reducing event. Such information is vital to formulating sound public policies for the highway infrastructure and its operation. This study is an initial attempt to provide nationwide estimates of the capacity losses and delay caused by temporary capacity-reducing events. The objective of this study was to develop and implement methods for producing national-level estimates of the loss of capacity on the nation's highway facilities due to temporary phenomena as well as estimates of the impacts of such losses. The estimates produced by this study roughly indicate the magnitude of problems that are likely be addressed by the Congress during the next re-authorization of the Surface Transportation Programs. The scope of the study includes all urban and rural freeways and principal arterials in the nation's highway system for 1999. Specifically, this study attempts to quantify the extent of temporary capacity losses due to crashes, breakdowns, work zones, weather, and sub-optimal signal timing. These events can cause impacts such as capacity reduction, delays, trip rescheduling, rerouting, reduced mobility, and reduced reliability. This study focuses on the reduction of capacity and resulting delays caused by the temporary events mentioned above. Impacts other than capacity losses and delay, such as re-routing, rescheduling, reduced mobility, and reduced reliability, are not covered in this phase of research.« less

Oxidative potential of on-road fine particulate matter (PM2.5) measured on major freeways of Los Angeles, CA, and a 10-year comparison with earlier roadside studies

NASA Astrophysics Data System (ADS)

Shirmohammadi, Farimah; Wang, Dongbin; Hasheminassab, Sina; Verma, Vishal; Schauer, James J.; Shafer, Martin M.; Sioutas, Constantinos

2017-01-01

This study describes on-road measurements of fine particulate matter (PM2.5) using a mobile instrumentation platform to assess the chemical composition and oxidative potential of PM2.5, using the dithiothreitol (DTT) assay, over three representative roadways in the Los Angeles Basin: the I-110 and I-710 freeways, the Wilshire/Sunset boulevards as well as the main campus of the University of Southern California (USC), used as a reference urban background site. Samples were chemically analyzed for elemental carbon (EC), organic carbon (OC), polycyclic aromatic hydrocarbons (PAHs) and 50 elements. The cumulative mass fraction of the measured PAHs was highest on the freeways (0.16 ± 0.01 and 0.15 ± 0.01 ng/μg PM, on I-110 and I-710, respectively); which on average was 3 and 3.3-fold higher than at Wilshire/Sunset and USC site, respectively. Mass fractions of Ba, Cr, Cu, Mn, Ni, Pb, Sb and Zn, tracers of vehicular abrasion, were 3.8 ± 0.8 times higher on both freeways in comparison to Wilshire/Sunset. The observed intrinsic (normalized per PM mass) DTT activity was greatest on freeways, averaging 30.13 ± 3.15 nmol/min mg PM and being roughly 1.9 and 2.1 times higher than the values obtained at Wilshire/Sunset and USC, respectively. Furthermore, comparison of our results with previous on-road and roadside studies conducted in the last decade in Los Angeles indicated an overall reduction in the contribution of carbonaceous species and PAHs (important tracers of exhaust emissions) to PM mass, especially on I-710 freeway with the higher heavy-duty diesel vehicle fraction, indicating the effectiveness of diesel vehicle emissions control policies implemented in recent years in California. In contrast, greater contributions of certain groups of metals and trace elements that are indicators of non-tailpipe emissions compared to previous studies provide evidence on the increasing importance of non-tailpipe emissions to the oxidative potential of on-road PM2.5 as vehicular exhaust emissions becomes cleaner. This finding was also reflected in the increased levels of on-road DTT activity by factors of 1.4-1.5 in comparison to the DTT activity of vehicular emissions estimated in previous dynamometer studies.

Using naturalistic driving study data to investigate the impact of driver distraction on driver's brake reaction time in freeway rear-end events in car-following situation.

PubMed

Gao, Jingru; Davis, Gary A

2017-12-01

The rear-end crash is one of the most common freeway crash types, and driver distraction is often cited as a leading cause of rear-end crashes. Previous research indicates that driver distraction could have negative effects on driving performance, but the specific association between driver distraction and crash risk is still not fully revealed. This study sought to understand the mechanism by which driver distraction, defined as secondary task distraction, could influence crash risk, as indicated by a driver's reaction time, in freeway car-following situations. A statistical analysis, exploring the causal model structure regarding drivers' distraction impacts on reaction times, was conducted. Distraction duration, distraction scenario, and secondary task type were chosen as distraction-related factors. Besides, exogenous factors including weather, visual obstruction, lighting condition, traffic density, and intersection presence and endogenous factors including driver age and gender were considered. There was an association between driver distraction and reaction time in the sample freeway rear-end events from SHRP 2 NDS database. Distraction duration, the distracted status when a leader braked, and secondary task type were related to reaction time, while all other factors showed no significant effect on reaction time. The analysis showed that driver distraction duration is the primary direct cause of the increase in reaction time, with other factors having indirect effects mediated by distraction duration. Longer distraction duration, the distracted status when a leader braked, and engaging in auditory-visual-manual secondary task tended to result in longer reaction times. Given drivers will be distracted occasionally, countermeasures which shorten distraction duration or avoid distraction presence while a leader vehicle brakes are worth considering. This study helps better understand the mechanism of freeway rear-end events in car-following situations, and provides a methodology that can be adopted to study the association between driver behavior and driving features. Copyright © 2017 National Safety Council and Elsevier Ltd. All rights reserved.

Impacts of carpool utilization on the Katy Freeway Transitway 42-month after evaluation. Interim report, September 1984-September 1989

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

Hawkins, H.G.; Christiansen, D.L.

1989-09-01

A major commitment has been made in the Houston area to develop physically separated transitways in the medians of freeways. The lanes are reserved for high-occupancy vehicles. Phase 1 of the first completed transitway opened on the Katy Freeway (I-10) in October 1984. The research study, funded jointly by the Metropolitan Transit Authority of Harris County and the Texas State Department of Highways and Public Transportation, was initiated in order to conduct a comprehensive analysis of the effects of permitting carpools to utilize the transitway. The report documents data collected in October 1988, 3.5 years after carpool utilization of themore » transitway began. The report compares the 1988 data to similar data collected before carpool utilization was permitted (March 1985) and after carpool utilization was permitted (April 1986, October 1987). These comparisons address numerous concerns and provide an indication of the effectiveness of allowing carpools on the transitway.« less

Impacts of carpool utilization on the Katy Freeway transitway 30-month after evaluation. Interim report, September 1984-April 1988

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

Christiansen, D.L.; McCasland, W.R.

1988-09-01

A major commitment has been made in the Houston area to develop physically separated transitways in the medians of freeways. The lanes are reserved for high-occupancy vehicles. Phase I of the first completed transitway opened on the Katy Freeway (I-10) in October 1984. Phase 2 opened in June 1987. To increase potential utilization of the facility, carpools began using the transitway on a test basis in April 1985. The research study, funded jointly by the Metropolitan Transit Authority of Harris County and the Texas State Department of Highways and Public Transportation, was initiated to undertake a comprehensive analysis of themore » effects of permitting carpool utilization. The report documents the data collected in October 1987, 2.5 years after carpool utilization of the transitway was permitted. In the report, these data are compared to similar data collected both before carpool utilization was permitted and on several occasions after carpool utilization was permitted.« less

Predicting reduced visibility related crashes on freeways using real-time traffic flow data.

PubMed

Hassan, Hany M; Abdel-Aty, Mohamed A

2013-06-01

The main objective of this paper is to investigate whether real-time traffic flow data, collected from loop detectors and radar sensors on freeways, can be used to predict crashes occurring at reduced visibility conditions. In addition, it examines the difference between significant factors associated with reduced visibility related crashes to those factors correlated with crashes occurring at clear visibility conditions. Random Forests and matched case-control logistic regression models were estimated. The findings indicated that real-time traffic variables can be used to predict visibility related crashes on freeways. The results showed that about 69% of reduced visibility related crashes were correctly identified. The results also indicated that traffic flow variables leading to visibility related crashes are slightly different from those variables leading to clear visibility crashes. Using time slices 5-15 minutes before crashes might provide an opportunity for the appropriate traffic management centers for a proactive intervention to reduce crash risk in real-time. Copyright © 2013 Elsevier Ltd. All rights reserved.

New findings regarding the significance of pavement skid resistance for road safety on Swiss freeways.

PubMed

Lindenmann, H P

2006-01-01

The significance of the influence of poor pavement skid resistance values on accident frequency in wet pavement conditions has been the object of many studies over several years. The various investigations have produced very diverse findings. Only seldom, however, has detailed consideration been given to the central question of whether pavement skid resistance is a decisive parameter in the occurrence of local accident "black spots." Until now, the focus has been more on describing a relationship between pavement skid resistance and accident frequency. In the course of the network-wide survey of the states of pavements and of accident occurrence on Switzerland's freeways from 1999 to 2003, it emerged that a relationship with inadequate pavement skid resistance was provable for only a small proportion of accident black spots. These findings were used to frame a guideline for authorities and highway operators about how to treat skid resistance when assessing pavements and accident occurrence on freeways.

Validation of Variations in Mental Workload as a Function of Scenario Difficulty: Traffic Density and Visibility

NASA Technical Reports Server (NTRS)

2003-01-01

Fluctuations in mental workload can be expected as a function of traffic density and visibility. The aim of the current investigation was to establish simulation scenarios that differed in attentional processing requirements. Four scenarios were created and tested representing two levels of traffic density (urban versus freeway) and two levels of visibility (clear versus foggy). An array of mental workload assessment measures were used to exam changes in attentional processing requirements in each scenario. The assessment array consisted of physiological (P300 amplitude and latency) and behavioral (RT and accuracy) indices. Preliminary results indicate that workload differs significantly as a function of traffic density in rural versus freeway scenarios. Workload also differs significantly in rural versus freeway scenarios as a function of visibility as observed by a significant interaction between the two variables of interest. Results are discussed in terms of their application for validating the difficulty level of simulation scenarios as a format for examining mental workload.

Driver performance and attention allocation in use of logo signs on freeway exit ramps.

PubMed

Zahabi, Maryam; Machado, Patricia; Lau, Mei Ying; Deng, Yulin; Pankok, Carl; Hummer, Joseph; Rasdorf, William; Kaber, David B

2017-11-01

The objective of this research was to quantify the effects of driver age, ramp signage configuration, including number of panels, logo format and sign familiarity, on driver performance and attention allocation when exiting freeways. Sixty drivers participated in a simulator study and analysis of variance models were used to assess response effects of the controlled manipulations. Results revealed elderly drivers to demonstrate worse performance and conservative control strategies as compared to middle-aged and young drivers. Elderly drivers also exhibited lower off-road fixation frequency and shorter off-road glance durations compared to middle-aged and young drivers. In general, drivers adopted a more conservative strategy when exposed to nine-panel signs as compared to six-panel signs and were more accurate in target detection when searching six-panels vs. nine and with familiar vs. unfamiliar logos. These findings provide an applicable guide for agency design of freeway ramp signage accounting for driver demographics. Copyright © 2017 Elsevier Ltd. All rights reserved.

Emissions from an international airport increase particle number concentrations 4-fold at 10 km downwind.

PubMed

Hudda, Neelakshi; Gould, Tim; Hartin, Kris; Larson, Timothy V; Fruin, Scott A

2014-06-17

We measured the spatial pattern of particle number (PN) concentrations downwind from the Los Angeles International Airport (LAX) with an instrumented vehicle that enabled us to cover larger areas than allowed by traditional stationary measurements. LAX emissions adversely impacted air quality much farther than reported in previous airport studies. We measured at least a 2-fold increase in PN concentrations over unimpacted baseline PN concentrations during most hours of the day in an area of about 60 km(2) that extended to 16 km (10 miles) downwind and a 4- to 5-fold increase to 8-10 km (5-6 miles) downwind. Locations of maximum PN concentrations were aligned to eastern, downwind jet trajectories during prevailing westerly winds and to 8 km downwind concentrations exceeded 75 000 particles/cm(3), more than the average freeway PN concentration in Los Angeles. During infrequent northerly winds, the impact area remained large but shifted to south of the airport. The freeway length that would cause an impact equivalent to that measured in this study (i.e., PN concentration increases weighted by the area impacted) was estimated to be 280-790 km. The total freeway length in Los Angeles is 1500 km. These results suggest that airport emissions are a major source of PN in Los Angeles that are of the same general magnitude as the entire urban freeway network. They also indicate that the air quality impact areas of major airports may have been seriously underestimated.

Driver speed selection on high-speed two-lane highways: Comparing speed profiles between uniform and differential speed limits.

PubMed

Russo, Brendan J; Savolainen, Peter T; Gates, Timothy J; Kay, Jonathan J; Frazier, Sterling

2017-07-04

Although a considerable amount of prior research has investigated the impacts of speed limits on traffic safety and operations, much of this research, and nearly all of the research related to differential speed limits, has been specific to limited access freeways. The unique safety and operational issues on highways without access control create difficulty relating the conclusions from prior freeway-related speed limit research to 2-lane highways, particularly research on differential limits due to passing limitations and subsequent queuing. Therefore, the objective of this study was to assess differences in driver speed selection with respect to the posted speed limit on rural 2-lane highways, with a particular emphasis on the differences between uniform and differential speed limits. Data were collected from nearly 59,000 vehicles across 320 sites in Montana and 4 neighboring states. Differences in mean speeds, 85th percentile speeds, and the standard deviation in speeds for free-flowing vehicles were examined across these sites using ordinary least squares regression models. Ultimately, the results of the analysis show that the mean speed, 85th percentile speed, and variability in travel speeds for free-flowing vehicles on 2-lane highways are generally lower at locations with uniform 65 mph speed limits, compared to locations with differential limits of 70 mph for cars and 60 mph for trucks. In addition to posted speed limits, several site characteristics were shown to influence speed selection including shoulder widths, frequency of horizontal curves, percentage of the segment that included no passing zones, and hourly volumes. Differences in vehicle speed characteristics were also observed between states, indicating that speed selection may also be influenced by local factors, such as driver population or enforcement.

Bus--carpool FWY lanes in San Francisco area

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

Newman, L.

1976-11-01

The California Department of Transportation is studying ways to increase the use of the urban freeway systems that will accommodate the maximum number of people with the least delay and the maximum possible safety in a cost-effective way. This paper describes operational features of four different projects under way, namely: a contraflow bus lane; a part-time bus lane in the same direction and unseparated from normal traffic; a bus-carpool lane also in the same direction and unseparated from normal traffic; and a preferential access to a metered freeway. (MCW)

Mitigating and Tracking Black Carbon Exposure at Schools in the Mountain View Corridor of Salt Lake City

NASA Astrophysics Data System (ADS)

Roberts, P. T.; Brown, S. G.; Vaughn, D.; DeWinter, J. L.

2015-12-01

Black carbon (BC) is a short lived climate forcer and is associated with human health effects. We measured BC inside and outside at four schools in Salt Lake City during two studies in 2011-2014. In addition, PM2.5 was measured indoor and outdoor at one school, and gaseous air toxics outdoor at one school. The schools are within 500 m of a planned major freeway, and two of them will adjoin the freeway. The objectives included determining the outdoor and indoor concentrations of BC, the likely sources of BC, and once the freeway is built, the change in ambient BC at the schools. We determined the current state of air quality outdoors at these schools, to provide baseline data for comparison when the major freeway is operational, and indoors as a baseline before installing improved filtration to reduce BC in classrooms. Using MATES IV cancer risk values, we found that diesel particulate matter, as indicated by ambient, outdoor BC measurements, was responsible for 84% of the cancer risk at the schools. The HVAC system was moderately effective at filtrating PM mass (73% reduction), but very poor at filtering BC (7%-34% reduction), indicating that air toxics risk is similar indoors and outdoors. Improved filtration devices could potentially mitigate this risk, and improved filtration systems have been recommended for the schools. Lastly, we used the difference in absorption at two Aethalometer channels to determine that the majority of BC (> 90%) during the spring through fall is from fossil fuel emissions.

The role of traffic noise on the association between air pollution and children's lung function.

PubMed

Franklin, Meredith; Fruin, Scott

2017-08-01

Although it has been shown that traffic-related air pollution adversely affects children's lung function, few studies have examined the influence of traffic noise on this association, despite both sharing a common source. Estimates of noise exposure (L dn, dB), and freeway and non-freeway emission concentrations of oxides of nitrogen (NO x , ppb) were spatially assigned to children in Southern California who were tested for forced vital capacity (FVC, n=1345), forced expiratory volume in 1s, (FEV 1, n=1332), and asthma. The associations between traffic-related NO x and these outcomes, with and without adjustment for noise, were examined using mixed effects models. Adjustment for noise strengthened the association between NO x and reduced lung function. A 14.5mL (95% CI -40.0, 11.0mL) decrease in FVC per interquartile range (13.6 ppb) in freeway NO x was strengthened to a 34.6mL decrease after including a non-linear function of noise (95% CI -66.3, -2.78mL). Similarly, a 6.54mL decrease in FEV 1 (95% CI -28.3, 15.3mL) was strengthened to a 21.1mL decrease (95% CI -47.6, 5.51) per interquartile range in freeway NO x . Our results indicate that where possible, noise should be included in epidemiological studies of the association between traffic-related air pollution on lung function. Without taking noise into account, the detrimental effects of traffic-related pollution may be underestimated. Copyright © 2017 Elsevier Inc. All rights reserved.

Emissions from an International Airport Increase Particle Number Concentrations 4-fold at 10 km Downwind

PubMed Central

2014-01-01

We measured the spatial pattern of particle number (PN) concentrations downwind from the Los Angeles International Airport (LAX) with an instrumented vehicle that enabled us to cover larger areas than allowed by traditional stationary measurements. LAX emissions adversely impacted air quality much farther than reported in previous airport studies. We measured at least a 2-fold increase in PN concentrations over unimpacted baseline PN concentrations during most hours of the day in an area of about 60 km2 that extended to 16 km (10 miles) downwind and a 4- to 5-fold increase to 8–10 km (5–6 miles) downwind. Locations of maximum PN concentrations were aligned to eastern, downwind jet trajectories during prevailing westerly winds and to 8 km downwind concentrations exceeded 75 000 particles/cm3, more than the average freeway PN concentration in Los Angeles. During infrequent northerly winds, the impact area remained large but shifted to south of the airport. The freeway length that would cause an impact equivalent to that measured in this study (i.e., PN concentration increases weighted by the area impacted) was estimated to be 280–790 km. The total freeway length in Los Angeles is 1500 km. These results suggest that airport emissions are a major source of PN in Los Angeles that are of the same general magnitude as the entire urban freeway network. They also indicate that the air quality impact areas of major airports may have been seriously underestimated. PMID:24871496

Sediment-induced amplification and the collapse of the Nimitz Freeway

USGS Publications Warehouse

Hough, S.E.; Friberg, P.A.; Busby, R.; Field, E.F.; Jacob, K.H.; Borcherdt, R.D.

1990-01-01

THE amplification of ground motion by low-seismic-velocity surface sediments is an important factor in determining the seismic hazard specific to a given site. The Ms = 7.1 Loma Prieta earthquake of 17 October 1989 was the largest event in the contiguous United States in 37 years, and yielded an unparalleled volume of seismic data from the main shock and aftershock sequence1. These data can be used to image the seismic source, to study detailed Earth structure, and to study the propagation of seismic waves both through bedrock at depth and through sediment layers near the surface. Near the edge of San Francisco Bay, site conditions vary considerably on scales of hundreds of metres. The collapsed section of the two-tiered Nimitz Freeway in Oakland was built on San Francisco Bay mud, whereas stiffer alluvial sediments underlie a southern section that was damaged but did not collapse. Here we analyse high-quality, digital aftershock recordings from several sites near the Nimitz Freeway, and conclude that soil conditions and resulting ground-motion amplification may have contributed significantly to the failure of the structure.

Assessing rear-end collision risk of cars and heavy vehicles on freeways using a surrogate safety measure.

PubMed

Zhao, Peibo; Lee, Chris

2018-04-01

This study analyzes rear-end collision risk of cars and heavy vehicles on freeways using a surrogate safety measure. The crash potential index (CPI) was modified to reflect driver's reaction time and estimated by types of lead and following vehicles (car or heavy vehicle). CPIs were estimated using the individual vehicle trajectory data from a segment of the US-101 freeway in Los Angeles, U.S.A. It was found that the CPI was generally higher for the following heavy vehicle than the following car due to heavy vehicle's lower braking capability. This study also validates the CPI using the simulated traffic data which replicate the observed traffic conditions a few minutes before the crash time upstream and downstream of the crash locations. The observed data were obtained from crash records and loop detectors on a section of the Gardiner Expressway in Toronto, Canada. The result shows that the values of CPI were consistently higher during the traffic conditions immediately before the crash time (crash case) than the normal traffic conditions (non-crash case). This demonstrates that the CPI can be used to capture rear-end collision risk during car-following maneuver on freeways. The result also shows that rear-end collision risk is lower for heavy vehicles than cars in the crash case due to their shorter reaction time and lower speed when spacing is shorter. Thus, it is important to reflect the differences in driver behavior and vehicle performance characteristics between cars and heavy vehicles in estimating surrogate safety measures. Lastly, it was found that the CPI-based crash prediction model can correctly identify the crash and non-crash cases at higher accuracy than the other crash prediction models based on detectors. Copyright © 2018 Elsevier Ltd. All rights reserved.

Assessing factors causing severe injuries in crashes of high-deck buses in long-distance driving on freeways.

PubMed

Chu, Hsing-Chung

2014-01-01

High-deck buses that have a higher center of gravity traveling at an excessive speed have a higher likelihood of causing serious and fatal accidents when drivers lose control of the vehicle. In addition, drivers who suffer from fatigue in long-distance driving increase the likelihood of serious accident. This paper examines the effects of risk factors contributing to severe crashes associated with high-deck buses used for long-distance driving on freeways. An ordered logit and latent class models are used to examine significant factors on the severity of injuries in crashes related to high-deck buses. Driver fatigue, drivers or passengers not wearing a seat belt, reckless driving, drunk driving, crashes occurred between midnight and dawn, and crashes occurred at interchange ramps were found to significantly affect the severity of injuries in crashes involving high-deck buses. Safety policies to prevent severe injuries in crashes involving high deck buses used for long-distance runs on freeways include: (1) restricting drivers from exceeding the limit of daily driving hours and mandating sufficient rest breaks; (2) installing an automatic sleep-warning device in the vehicle; (3) drivers with obstructive sleep apnea syndrome or sleep disorders should be tested and treated before they are allowed to perform long hours of driving tasks; (4) educating the public or even amending the seatbelt legislation to require all passengers to wear a seat belt and thus reduce the chance of ejection from a high-deck bus and prevent serious injuries in a crash while traveling at a higher speed on freeways. Copyright © 2013 Elsevier Ltd. All rights reserved.

Evidence for the accumulation of atmospheric lead by insects in areas of high traffic density

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

Giles, F.E.; Middleton, S.G.; Grau, J.G.

1973-04-01

This study followed the path of lead through an insect food chain. The site chosen was 4 km north of the city of Baltimore, adjacent to a major freeway. The lead content of various specimens was assayed. Higher concentrations of Pb found in wild carrot and evening primrose that grew near the freeway indicated that the conditions in the test area were similar to those of land adjacent to high density thoroughfares reported earlier. These plants were hosts for Japanese beetles. The damselfly collected showed higher concentrations in July, but less in August; therefore no significant differences. The most strikingmore » differences in lead concentration were exhibited by the European mantid. All freeway samples of the species showed significantly higher concentrations of lead than control samples, but nymphs collected on August 13 had higher concentrations than did samples of teneral images taken August 31. Lead might possibly be stored in the exoskeleton, which upon being shed would cause a lower lead reading. It was presumed that measurable amounts of atmospheric lead are being concentrated by insect predators, at least during the later part of the season. 5 references, 1 table.« less

Mapping Surface Features Produced by an Active Landslide

NASA Astrophysics Data System (ADS)

Parise, Mario; Gueguen, Erwan; Vennari, Carmela

2016-10-01

A large landslide reactivated on December 2013, at Montescaglioso, southern Italy, after 56 hours of rainfall. The landslide disrupted over 500 m of a freeway, involved a few warehouses, a supermarket, and private homes. After the event, it has been performed field surveys, aided by visual analysis of terrestrial and helicopter photographs, to compile a map of the surface deformations. The geomorphological features mapped included single fractures, sets of fractures, tension cracks, trenches, and pressure ridges. In this paper we present the methodology used, the map obtained through the intensive field work, and discuss the main surface features produced by the landslide.

Impacts of carpool utilization on the Katy Freeway authorized vehicle lane 12-month after evaluation. Interim report, September 1984-August 1986

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

Christiansen, D.L.; McCasland, W.R.

1986-08-01

The report documents the data collected in April through June 1986, one year after carpool utilization of the authorized vehicle lane (AVL) was permitted. Comprehensive traffic data, both on the AVL and the freeway, were collected. In addition, surveys of transit users on the AVL, vanpool drivers on the AVL, vanpool passengers on the AVL, carpool drivers on the AVL, carpool passengers on the AVL, and motorists not using the AVL were undertaken. In the report, these data are compared to similar data collected before carpool utilization was permitted to identify the impacts of permitting carpools to use the AVL.

An open-closed-loop iterative learning control approach for nonlinear switched systems with application to freeway traffic control

NASA Astrophysics Data System (ADS)

Sun, Shu-Ting; Li, Xiao-Dong; Zhong, Ren-Xin

2017-10-01

For nonlinear switched discrete-time systems with input constraints, this paper presents an open-closed-loop iterative learning control (ILC) approach, which includes a feedforward ILC part and a feedback control part. Under a given switching rule, the mathematical induction is used to prove the convergence of ILC tracking error in each subsystem. It is demonstrated that the convergence of ILC tracking error is dependent on the feedforward control gain, but the feedback control can speed up the convergence process of ILC by a suitable selection of feedback control gain. A switched freeway traffic system is used to illustrate the effectiveness of the proposed ILC law.

Impacts of carpool utilization on the Katy Freeway transitway, 54-month after evaluation. Interim report, Sep 84-Sep 90

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

Bullard, D.L.

1990-09-01

Within the Houston metropolitan area, a major commitment has been made to develop a system of physically separated transitways in the medians of the existing freeway network. These lanes are reserved for the exclusive use of high-occupancy vehicles. Phase 1 of the first completed transitway opened on the Katy Freeway (I-10W) in October 1984. Initially, only authorized buses and vanpools were designated as eligible users of the transitway. To encourage increased vehicular utilization of the facility, carpools were allowed to use the transitway on a test basis beginning in April 1985. The research study, sponsored by the Metropolitan Transit Authoritymore » of Harris County and the Texas State Department of Highways and Public Transportation, was initiated in order to conduct a comprehensive analysis of the effects of permitting carpools to use the transitway. The report documents data collected in October 1989, 4.5 years after carpool utilization of the transitway began. The report compares the 1989 data to similar data collected before carpool utilization was permitted (March 1985) and after carpool utilization was permitted (April 1986, October 1987, October 1988). These comparisons address numerous concerns and provide an indication of the effectiveness of allowing carpools onto the transitway.« less

Public health assessment for Freeway Sanitary Landfill, Burnsville, Dakota County, Minnesota, Region 5. CERCLIS No. MND038384004. Final report

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

Not Available

1993-03-30

The Freeway Sanitary Landfill National Priorities List (NPL) site in Burnsville, Minnesota is situated in the Lower Minnesota River Valley. Shallow groundwater beneath the site is contaminated with low levels of volatile organic hydrocarbons and heavy metals. Under current conditions, no human exposures to site-related contaminants are known to occur at levels of health concern. Based on currently available information, the Minnesota Department of Health concludes that the site poses an indeterminate public health hazard under current conditions because exposure to volatile gases released to the air is possible, but cannot be evaluated from the very limited information available. Theremore » are also a few physical hazards on the site which pose a risk of accident or injury if trespassing occurs. Otherwise, there are no indications that people have been, or are being, exposed to site-related contaminants at levels that would be of health concern. The Agency For Toxic Substances and Disease Registry (ATSDR) Health Activities Recommendation Panel has evaluated the Freeway Sanitary Landfill Public Health Assessment for appropriate follow-up activities. The Panel has recommended that health education be considered to assist site workers in better understanding their potential for exposure to landfill gases.« less

Modelling dynamics with context-free grammars

NASA Astrophysics Data System (ADS)

García-Huerta, Juan-M.; Jiménez-Hernández, Hugo; Herrera-Navarro, Ana-M.; Hernández-Díaz, Teresa; Terol-Villalobos, Ivan

2014-03-01

This article presents a strategy to model the dynamics performed by vehicles in a freeway. The proposal consists on encode the movement as a set of finite states. A watershed-based segmentation is used to localize regions with high-probability of motion. Each state represents a proportion of a camera projection in a two-dimensional space, where each state is associated to a symbol, such that any combination of symbols is expressed as a language. Starting from a sequence of symbols through a linear algorithm a free-context grammar is inferred. This grammar represents a hierarchical view of common sequences observed into the scene. Most probable grammar rules express common rules associated to normal movement behavior. Less probable rules express themselves a way to quantify non-common behaviors and they might need more attention. Finally, all sequences of symbols that does not match with the grammar rules, may express itself uncommon behaviors (abnormal). The grammar inference is built with several sequences of images taken from a freeway. Testing process uses the sequence of symbols emitted by the scenario, matching the grammar rules with common freeway behaviors. The process of detect abnormal/normal behaviors is managed as the task of verify if any word generated by the scenario is recognized by the grammar.

Statistical Characteristics of Wrong-Way Driving Crashes on Illinois Freeways.

PubMed

Zhou, Huaguo; Zhao, Jiguang; Pour-Rouholamin, Mahdi; Tobias, Priscilla A

2015-01-01

Driving the wrong way on freeways, namely wrong-way driving (WWD), has been found to be a major concern for more than 6 decades. The purpose of this study was to identify characteristics of this type of crash as well as to rank the locations/interchanges according to their vulnerability to WWD entries. The WWD crash data on Illinois freeways were statistically analyzed for a 6-year time period (2004 to 2009) from 3 aspects: crash, vehicle, and person. The temporal distributions, geographical distributions, roadway characteristics, and crash locations were analyzed for WWD crashes. The driver demographic information, physical condition, and injury severity were analyzed for wrong-way drivers. The vehicle characteristics, vehicle operation, and collision results were analyzed for WWD vehicles. A method was brought about to identify wrong-way entry points that was then used to develop a relative-importance technique and rank different interchange types in terms of potential WWD incidents. The findings revealed that a large proportion of WWD crashes occurred during the weekend from midnight to 5 a.m. Approximately 80% of WWD crashes were located in urban areas and nearly 70% of wrong-way vehicles were passenger cars. Approximately 58% of wrong-way drivers were driving under the influence (DUI). Of those, nearly 50% were confirmed to be impaired by alcohol, about 4% were impaired by drugs, and more than 3% had been drinking. The analysis of interchange ranking found that compressed diamond interchanges, single point diamond interchanges (SPDIs), partial cloverleaf interchanges, and freeway feeders had the highest wrong-way crash rates (wrong-way crashes per 100 interchanges per year). The findings of this study call for more attention to WWD crashes from different aspects such as driver age group, time of day, day of week, and DUI drivers. Based on the analysis results of WWD distance, the study explained why a 5-mile radius of WWD crash location should be studied for WWD fatal crashes with unknown entry points.

Transforming growth factor- 1 C-509T polymorphism, oxidant stress, and early-onset childhood asthma.

PubMed

Salam, Muhammad T; Gauderman, W James; McConnell, Rob; Lin, Pi-Chu; Gilliland, Frank D

2007-12-15

Transforming growth factor (TGF)-beta1 is involved in airway inflammation and remodeling, two key processes in asthma pathogenesis. Tobacco smoke and traffic emissions induce airway inflammation and modulate TGF-beta1 gene expression. We hypothesized that the effects of functional TGF-beta1 variants on asthma occurrence vary by these exposures. We tested these hypotheses among 3,023 children who participated in the Children's Health Study. Tagging single-nucleotide polymorphisms rs4803457 C>T and C-509T (a functional promoter polymorphism) accounted for 94% of the haplotype diversity of the upstream region. Exposure to maternal smoking in utero was based on smoking by biological mother during pregnancy. Residential distance from nearest freeway was calculated based on residential address at study entry. Children with the -509TT genotype had a 1.8-fold increased risk of early persistent asthma (95% confidence interval [CI], 1.11-2.95). This association varied marginally significantly by in utero exposure to maternal smoking. Compared with children with the -509CC/CT genotype with no in utero exposure to maternal smoking, those with the -509TT genotype with such exposure had a 3.4-fold increased risk of early persistent asthma (95% CI, 1.46-7.80; interaction, P = 0.11). The association between TGF-beta1 C-509T and lifetime asthma varied by residential proximity to freeways (interaction P = 0.02). Children with the -509TT genotype living within 500 m of a freeway had over three-fold increased lifetime asthma risk (95% CI, 1.29-7.44) compared with children with CC/CT genotype living > 1500 m from a freeway. Children with the TGF-beta1 -509TT genotype are at increased risk of asthma when they are exposed to maternal smoking in utero or to traffic-related emissions.

A case study of exposure to ultrafine particles from secondhand tobacco smoke in an automobile.

PubMed

Liu, S; Zhu, Y

2010-10-01

Secondhand tobacco smoke (SHS) in enclosed spaces is a major source of potentially harmful airborne particles. To quantify exposure to ultrafine particles (UFP) because of SHS and to investigate the interaction between pollutants from SHS and vehicular emissions, number concentration and size distribution of UFP and other air pollutants (CO, CO(2) , and PM(2.5)) were measured inside a moving vehicle under five different ventilation conditions. A major interstate freeway with a speed limit of 60 mph and an urban roadway with a speed limit of 30 mph were selected to represent typical urban routes. In a typical 30-min commute on urban roadways, the SHS of one cigarette exposed passengers to approximately 10 times the UFP and 120 times the PM(2.5) of ambient air. The most effective solution to protect passengers from SHS exposure is to abstain from smoking in the vehicle. Opening a window is an effective method for decreasing pollutant exposures on most urban roadways. However, under road conditions with high UFP concentrations, such as tunnels or busy freeways with high proportion of heavy-duty diesel trucks (such as the 710 Freeway in Los Angeles, CA, USA), opening a window is not a viable method to reduce UFPs. Time budget studies show that Americans spend, on average, more than 60 min each day in enclosed vehicles. Smoking inside vehicles can expose the driver and other passengers to high levels of pollutants. Thus, an understanding of the variations and interactions of secondhand tobacco smoke (SHS) and vehicular emissions under realistic driving conditions is necessary. Results of this study indicated that high ventilation rates can effectively dilute ultrafine particles (UFP) inside moving vehicles on urban routes. However, driving with open windows and an increased air exchange rate (AER) are not recommended on tunnels and heavily travelled freeways.

Near-Roadway Emission of Reactive Nitrogen Compounds and Other Non-Criteria Pollutants at a Southern California Freeway Site

NASA Astrophysics Data System (ADS)

Moss, J. A.; Baum, M.; Castonguay, A. E.; Aguirre, V., Jr.; Pesta, A.; Fanter, R. K.; Anderson, M.

2015-12-01

Emission control systems in light-duty motor vehicles (LDMVs) have played an important role in improving regional air quality by dramatically reducing the concentration of criteria pollutants (carbon monoxide, hydrocarbons, and nitrogen oxides) in exhaust emissions. Unintended side-reactions occurring on the surface of three-way catalysts may lead to emission of a number of non-criteria pollutants whose identity and emission rates are poorly understood. A series of near-roadway field studies conducted between 2009-2015 has investigated LDMV emissions of these pollutants with unprecedented depth of coverage, including reactive nitrogen compounds (NH3, amines, HCN, HONO, and HNO3), organic peroxides, and carbonyl compounds (aldehydes, ketones, and carboxylic acids). Methods to collect these pollutants using mist chambers, annular denuders, impingers, and solid-phase cartridges and quantify their concentration using GC-MS, LC-MS/MS, IC, and colorimetry were developed and validated in the laboratory and field. These methods were subsequently used in near-roadway field studies where the concentrations of the target compounds integrated over 1-4 hour blocks were measured at the edge of a freeway and at a background site 140 m from the roadway. Concentrations followed a steep decreasing gradient from the freeway to the background site. Emission factors (pollutant mass emitted per mass fuel consumed) were calculated by carbon mass balance using the difference in concentration measured between the freeway and background sites for the emitted pollutant and CO2 as a measure of carbon mass in the vehicle exhaust. The significance of these results will be discussed in terms of emissions inventories in the South Coast Air Basin of California, emission trends at this site over the period of 2009-2015, and for NH3, emission measurements conducted by our group and others over the period 2000-2015.

Rehabilitation strategies for partially edentulous-prosthodontic principles and current trends.

PubMed

D'Souza, Dsj; Dua, Parag

2011-07-01

The prosthetic considerations for treatment of partially edentulous patients involve evaluation of important aspects such as presence of certain functional or skeletal deficits, orientation of the occlusal plane, free-way space, size and location of edentulous areas, number, strategic location and quality of the likely abutment teeth, vertical dimension, and the type of occlusion. A comprehensive evaluation, multidisciplinary approach and a sequential treatment plan, worked out in harmony with the patient's perceptions are important factors to ensure a successful outcome. This article discusses the principles, current trends and importance of clinical decisions in designing a treatment strategy when confronted with complex situations of partial edentulism.

Head and cervical spine postures in complete denture wearers.

PubMed

Salonen, M A; Raustia, A M; Huggare, J

1993-01-01

Signs and symptoms in the stomatognathic system and head and cervical spine postures were evaluated in 10 edentulous patients prior to renewal of their dentures, as well as immediately and six months after insertion of new dentures. Natural head posture was recorded using the fluid-level method and measured from the roentgen cephalograms. It was shown that the variables duration of edentulousness and free-way space displayed positive correlations with the dysfunction symptoms. In addition, the patients who needed oral rehabilitation the most, who received the greatest reduction in their free-way space, were seen to have raised their heads more than average. There was also an inverse correlation between the reduction of clinical dysfunction index score and cervical spine postures.

Impact of traffic oscillations on freeway crash occurrences.

PubMed

Zheng, Zuduo; Ahn, Soyoung; Monsere, Christopher M

2010-03-01

Traffic oscillations are typical features of congested traffic flow that are characterized by recurring decelerations followed by accelerations (stop-and-go driving). The negative environmental impacts of these oscillations are widely accepted, but their impact on traffic safety has been debated. This paper describes the impact of freeway traffic oscillations on traffic safety. This study employs a matched case-control design using high-resolution traffic and crash data from a freeway segment. Traffic conditions prior to each crash were taken as cases, while traffic conditions during the same periods on days without crashes were taken as controls. These were also matched by presence of congestion, geometry and weather. A total of 82 cases and about 80,000 candidate controls were extracted from more than three years of data from 2004 to 2007. Conditional logistic regression models were developed based on the case-control samples. To verify consistency in the results, 20 different sets of controls were randomly extracted from the candidate pool for varying control-case ratios. The results reveal that the standard deviation of speed (thus, oscillations) is a significant variable, with an average odds ratio of about 1.08. This implies that the likelihood of a (rear-end) crash increases by about 8% with an additional unit increase in the standard deviation of speed. The average traffic states prior to crashes were less significant than the speed variations in congestion. Published by Elsevier Ltd.

Remote sensing in Michigan for land resource management: Highway impact assessment

NASA Technical Reports Server (NTRS)

1972-01-01

An existing section of M-14 freeway constructed in 1964 and a potential extension from Ann Arbor to Plymouth, Michigan provided an opportunity for investigating the potential uses of remote sensing techniques in providing projective information needed for assessing the impact of highway construction. Remote sensing data included multispectral scanner imagery and aerial photography. Only minor effects on vegetation, soils, and land use were found to have occurred in the existing corridor. Adverse changes expected to take place in the corridor proposed for extension of the freeway can be minimized by proper design of drainage ditches and attention to good construction practices. Remote sensing can be used to collect and present many types of data useful for highway impact assessment on land use, vegetation categories and species, soil properties and hydrologic characteristics.

Effects of roadside memorials on traffic flow.

PubMed

Tay, Richard; Churchill, Anthony; de Barros, Alexandre G

2011-01-01

Despite their growing popularity in North America, little research has been conducted on understanding the effects of roadside memorials on drivers' behaviour. In this study, we examined the short-term effects of roadside memorials on traffic speed and headways on a high speed intercity freeway as well as its long-term effect on traffic speed on a high speed urban freeway. Our study found that the placement of roadside memorials did not have any significant effect on traffic speeds or headways, either in the short or long term. Therefore, concerns about the negative effects on driver behaviour were not supported by this research, at least with regards to speeding and following too closely. However, no positive effects on safety were found either. Copyright © 2010 Elsevier Ltd. All rights reserved.

TENANT HOUSE, WINDOW DETAIL, NORTH FRONT, LOOKING SOUTH Irvine ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

TENANT HOUSE, WINDOW DETAIL, NORTH FRONT, LOOKING SOUTH - Irvine Ranch Agricultural Headquarters, Carillo Tenant House, Southwest of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

GARAGE, SOUTH (REAR) AND EAST SIDE, LOOKING NORTHWEST Irvine ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

GARAGE, SOUTH (REAR) AND EAST SIDE, LOOKING NORTHWEST - Irvine Ranch Agricultural Headquarters, Carillo Tenant House, Southwest of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

GARDEN (FOREGROUND), GARAGE (CENTER), AND PUMPHOUSE, LOOKING NORTHWEST Irvine ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

GARDEN (FOREGROUND), GARAGE (CENTER), AND PUMPHOUSE, LOOKING NORTHWEST - Irvine Ranch Agricultural Headquarters, Carillo Tenant House, Southwest of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

A comparative assessment of PM2.5 exposures in light-rail, subway, freeway, and surface street environments in Los Angeles and estimated lung cancer risk.

PubMed

Kam, Winnie; Delfino, Ralph J; Schauer, James J; Sioutas, C

2013-01-01

According to the U.S. Census Bureau, 570000+ commuters in Los Angeles travel for over 60 minutes to work. Studies have shown that a substantial portion of particulate matter (PM) exposure can occur during this commute. This study represents the integration of the results from five commute environments in Los Angeles. Personal PM exposures are discussed for the: (1) METRO gold line, a ground-level light-rail route, (2) METRO red line, a subway line, (3) the 110, a high volume freeway with low heavy-duty vehicle (HDV) fraction, (4) the 710, a major corridor for HDVs from the Port of Los Angeles, and (5) Wilshire/Sunset Boulevards, major surface streets. Chemical analysis including total and water-soluble metals and trace elements, elemental and organic carbon (EC/OC), and polycyclic aromatic hydrocarbons (PAHs) was performed. The focus of this study is to compare the composition and estimated lung cancer risk of PM2.5 (dp < 2.5 μm) for the five differential commute environments. Metals associated with stainless steel, notably Fe, Cr, and Mn, were elevated for the red line (subway), most likely from abrasion processes between the rail and brakes; elements associated with tire and brake wear and oil additives (Ca, Ti, Sn, Sb, and Pb) were elevated on roadways. Elemental concentrations on the gold line (light-rail) were the lowest. For water-solubility, metals observed on the red line (subway) were the least soluble. PAHs are primarily derived from vehicular emissions. Overall, the 710 exhibited high levels of PAHs (3.0 ng m−3), most likely due to its high volume of HDVs, while the red and gold lines exhibited low PAH concentrations (0.6 and 0.8 ng m−3 for red and gold lines, respectively). Lastly, lung cancer risk due to inhalation of PAHs was calculated based on a commuter lifetime (45 years for 2 hours per workday). Results showed that lung cancer risk for the 710 is 3.8 and 4.5 times higher than the light-rail (gold line) and subway (red line), respectively. With low levels of both metal and PAH pollutants, our results indicate that commuting on the light-rail (gold line) may have potential health benefits when compared to driving on freeways and busy roadways.

Control Strategies for Corridor Management

DOT National Transportation Integrated Search

2016-06-28

Integrated management of travel corridors comprising of freeways and adjacent arterial streets can potentially improve the performance of the highway facilities. However, several research gaps exist in data collection and performance measurement, ana...

Connected vehicle freeway speed harmonization systems.

DOT National Transportation Integrated Search

2016-03-15

The capacity drop phenomenon, which reduces the maximum bottleneck discharge rate following the onset of congestion, is a critical restriction in transportation networks that causes additional traffic congestion. Consequently, preventing or reducing ...

BARBEQUE PIT AND PLAYHOUSE IN (REAR) YARD, LOOKING SOUTH ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

BARBEQUE PIT AND PLAYHOUSE IN (REAR) YARD, LOOKING SOUTH - Irvine Ranch Agricultural Headquarters, Carillo Tenant House, Southwest of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

Everett Weinreb, Photographer, April 1989 WATER TANK, LOOKING SOUTHEAST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Everett Weinreb, Photographer, April 1989 WATER TANK, LOOKING SOUTHEAST - Irvine Ranch Agricultural Headquarters, Boyd Tenant House, Southeast of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

On-road emission factors of PM pollutants for light-duty vehicles (LDVs) based on urban street driving conditions

NASA Astrophysics Data System (ADS)

Kam, Winnie; Liacos, James W.; Schauer, James J.; Delfino, Ralph J.; Sioutas, Constantinos

2012-12-01

An on-road sampling campaign was conducted on two major surface streets (Wilshire and Sunset Boulevards) in Los Angeles, CA, to characterize PM components including metals, trace elements, and organic species for three PM size fractions (PM10-2.5, PM2.5-0.25, and PM0.25). Fuel-based emission factors (mass of pollutant per kg of fuel) were calculated to assess the emissions profile of a light-duty vehicle (LDV) traffic fleet characterized by stop-and-go driving conditions that are reflective of urban street driving. Emission factors for metals and trace elements were highest in PM10-2.5 while emission factors for PAHs and hopanes and steranes were highest in PM0.25. PM2.5 emission factors were also compared to previous freeway, roadway tunnel, and dynamometer studies based on an LDV fleet to determine how various environments and driving conditions may influence concentrations of PM components. The on-road sampling methodology deployed in the current study captured substantially higher levels of metals and trace elements associated with vehicular abrasion (Fe, Ca, Cu, and Ba) and crustal origins (Mg and Al) than previous LDV studies. The semi-volatile nature of PAHs resulted in higher levels of PAHs in the particulate phase for LDV tunnel studies (Phuleria et al., 2006) and lower levels of PAHs in the particulate phase for freeway studies (Ning et al., 2008). With the exception of a few high molecular weight PAHs, the current study's emission factors were in between the LDV tunnel and LDV freeway studies. In contrast, hopane and sterane emission factors were generally comparable between the current study, the LDV tunnel, and LDV freeway, as expected given the greater atmospheric stability of these organic compounds. Overall, the emission factors from the dynamometer studies for metals, trace elements, and organic species are lower than the current study. Lastly, n-alkanes (C19-C40) were quantified and alkane carbon preference indices (CPIs) were determined to be in the range of 1-2, indicating substantial anthropogenic source contribution for surface streets in Los Angeles.

Effect of driver's age and side of impact on crash severity along urban freeways: a mixed logit approach.

PubMed

Haleem, Kirolos; Gan, Albert

2013-09-01

This study identifies geometric, traffic, environmental, vehicle-related, and driver-related predictors of crash injury severity on urban freeways. The study takes advantage of the mixed logit model's ability to account for unobserved effects that are difficult to quantify and may affect the model estimation, such as the driver's reaction at the time of crash. Crashes of 5 years occurring on 89 urban freeway segments throughout the state of Florida in the United States were used. Examples of severity predictors explored include traffic volume, distance of the crash to the nearest ramp, and detailed driver's age, vehicle types, and sides of impact. To show how the parameter estimates could vary, a binary logit model was compared with the mixed logit model. It was found that the at-fault driver's age, traffic volume, distance of the crash to the nearest ramp, vehicle type, side of impact, and percentage of trucks significantly influence severity on urban freeways. Additionally, young at-fault drivers were associated with a significant severity risk increase relative to other age groups. It was also observed that some variables in the binary logit model yielded illogic estimates due to ignoring the random variation of the estimation. Since the at-fault driver's age and side of impact were significant random parameters in the mixed logit model, an in-depth investigation was performed. It was noticed that back, left, and right impacts had the highest risk among middle-aged drivers, followed by young drivers, very young drivers, and finally, old and very old drivers. To reduce side impacts due to lane changing, two primary strategies can be recommended. The first strategy is to conduct campaigns to convey the hazardous effect of changing lanes at higher speeds. The second is to devise in-vehicle side crash avoidance systems to alert drivers of a potential crash risk. The study provided a promising approach to screening the predictors before fitting the mixed logit model using the random forest technique. Furthermore, potential countermeasures were proposed to reduce the severity of impacts. Copyright © 2013 National Safety Council and Elsevier Ltd. All rights reserved.

Lane Blockage Effects on Freeway Traffic Flow

DOT National Transportation Integrated Search

1996-09-01

Intelligent Transportation Systems (ITS) apply advanced and emerging technologies in such fields as information processing, communications, control, and electronics to surface transportation needs. ITS encompasses a number of diverse program areas in...

Quantifying travel time variability in transportation networks.

DOT National Transportation Integrated Search

2010-03-01

Nonrecurring congestion creates significant delay on freeways in urban areas, lending importance : to the study of facility reliability. In locations where traffic detectors record and archive data, : approximate probability distributions for travel ...

GARAGE (L) IN RELATION TO TENANT HOUSE (R), LOOKING SOUTHWEST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

GARAGE (L) IN RELATION TO TENANT HOUSE (R), LOOKING SOUTHWEST - Irvine Ranch Agricultural Headquarters, Carillo Tenant House, Southwest of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

Vision statement.

DOT National Transportation Integrated Search

2003-09-01

This document is the third such handbook for freeway management and operations. It is intended to be an introductory manual a resource document that provides an overview of the various institutional and technical issues associated with the planni...

Validation of urban freeway models.

DOT National Transportation Integrated Search

2015-01-01

This report describes the methodology, data, conclusions, and enhanced models regarding the validation of two sets of models developed in the Strategic Highway Research Program 2 (SHRP 2) Reliability Project L03, Analytical Procedures for Determining...

HOV Lane Violation Study

DOT National Transportation Integrated Search

1990-01-01

In an attempt to cope with the traffic congestion caused by the rapid growth of : suburban populations and the relative decline in funds and space for additional : freeway construction, the California Department of Transportation (CALTRANS) has : int...

Heavy vehicle effects on Florida freeways and multilane highways.

DOT National Transportation Integrated Search

2013-10-01

The Florida Department of Transportations (FDOT) primary guide for conducting highway capacity and level of : service analyses from planning through design is the Transportation Research Boards Highway Capacity Manual (HCM). : FDOTs FREEPLAN...

Arterial management.

DOT National Transportation Integrated Search

2004-04-01

In many major metropolitan areas, the freeway system is : functioning at or beyond the capacity for which it was : designed. Many drivers are choosing to use arterial streets : instead. The resulting stress on the arterial systems creates : gridlock ...

Toward a best practice model for managed lanes in Texas.

DOT National Transportation Integrated Search

2013-09-01

Increasing implementation of managed lanes in the : United States : Katy Freeway Managed Lanes : (KML) offers lessons learned : for other projects : First operational, multilane, : variably priced, managed facility : in Texas : Became oper...

The mass media and disasters

USGS Publications Warehouse

Rogers, E. M.

1990-01-01

Past investigations by myself and others on the role of the mass media in disasters indicate that news people typically find themselves in situations of uncertainty, ambiguity, and conflicting information; the communication and transportation services that these people use in covering a story become inoperative. However, the media are expected to make sense of the disaster situation almost immediately. the difficulties of doing so were reflected by the ABC Goodyear Blimp footage of the collapsed Nimitz Freeway in Oakland, California, broadcast nationally on the evening of October 17, 1989. The televised picture showed the disastrous results of the Loma Prieta earthquake, but for an hour or more the announcer could not correctly identify what was being shown. He did not seem to realize that the upper deck of the freeway had collapsed on the lower deck, crushing vechiles and people. 

Evaluating the safety impact of adaptive cruise control in traffic oscillations on freeways.

PubMed

Li, Ye; Li, Zhibin; Wang, Hao; Wang, Wei; Xing, Lu

2017-07-01

Adaptive cruise control (ACC) has been considered one of the critical components of automated driving. ACC adjusts vehicle speeds automatically by measuring the status of the ego-vehicle and leading vehicle. Current commercial ACCs are designed to be comfortable and convenient driving systems. Little attention is paid to the safety impacts of ACC, especially in traffic oscillations when crash risks are the highest. The primary objective of this study was to evaluate the impacts of ACC parameter settings on rear-end collisions on freeways. First, the occurrence of a rear-end collision in a stop-and-go wave was analyzed. A car-following model in an integrated ACC was developed for a simulation analysis. The time-to-collision based factors were calculated as surrogate safety measures of the collision risk. We also evaluated different market penetration rates considering that the application of ACC will be a gradual process. The results showed that the safety impacts of ACC were largely affected by the parameters. Smaller time delays and larger time gaps improved safety performance, but inappropriate parameter settings increased the collision risks and caused traffic disturbances. A higher reduction of the collision risk was achieved as the ACC vehicle penetration rate increased, especially in the initial stage with penetration rates of less than 30%. This study also showed that in the initial stage, the combination of ACC and a variable speed limit achieved better safety improvements on congested freeways than each single technique. Copyright © 2017 Elsevier Ltd. All rights reserved.

Highway planning and operations for the Dallas district: Implementation and evaluation of concurrent flow HOV lanes in Texas. Project summary report 1994-14S, September 1996--August 1997

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

Skowronek, D.A.; Stoddard, A.M.; Ranft, S.E.

1997-11-01

Limited capital investment for major transportation improvements and growth in metropolitan areas require the most efficient use of the existing transportation system. One means to achieve this is high-occupancy vehicle (HOV) lanes. While an extensive system of permanent HOV lanes is planned for the Dallas-Fort Worth urbanized area, the Texas Department of Transportation (TxDOT) and Dallas Area Rapid Transit (DART) have pursued and continue to pursue short-term or interim HOV lane projects that would enhance public transportation and overall mobility. There are currently 57 km (35.4 mi) of interim HOV lanes operational in the Dallas area, including a barrier-separated contraflowmore » lane on I-30 (East R.L. Thornton Freeway) and buffer-separated concurrent flow HOV lanes on I-35E North (Stemmons Freeway) and I-635 (Lyndon B. Johnson Freeway). The objective of this research is to investigate the operational effectiveness of concurrent flow (buffer-separated) versus contraflow (barrier-separated) HOV lanes. Issues such as person movement, carpool formation, travel time savings, violation rates, and project cost effectiveness are addressed. By understanding the operational performance and issues of both concurrent flow (buffer-separated) HOV lanes and contraflow (barrier-separated) HOV lanes, recommendations can be made on suggested HOV lane policies, including the type of permanent HOV lanes to be implemented in the Dallas area.« less

CHICKEN COOP BEHIND FENCED YARD AND (REAR) OF BARBEQUE PIT, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

CHICKEN COOP BEHIND FENCED YARD AND (REAR) OF BARBEQUE PIT, LOOKING NORTH - Irvine Ranch Agricultural Headquarters, Carillo Tenant House, Southwest of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

TENANT HOUSE INTERIOR, DOOR DETAIL, FRONT ENTRANCE INTO LIVING ROOM, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

TENANT HOUSE INTERIOR, DOOR DETAIL, FRONT ENTRANCE INTO LIVING ROOM, LOOKING NORTH - Irvine Ranch Agricultural Headquarters, Carillo Tenant House, Southwest of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

Everett Weinreb, Photographer, April 1989 GARAGE BEHIND HOUSE, EAST (FRONT), ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Everett Weinreb, Photographer, April 1989 GARAGE BEHIND HOUSE, EAST (FRONT), LOOKING WEST - Irvine Ranch Agricultural Headquarters, Boyd Tenant House, Southeast of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

Everett Weinreb, Photographer, April 1989 GARAGE BEHIND HOUSE, WEST (REAR), ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Everett Weinreb, Photographer, April 1989 GARAGE BEHIND HOUSE, WEST (REAR), LOOKING NORTHEAST - Irvine Ranch Agricultural Headquarters, Boyd Tenant House, Southeast of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

Everett Weinreb, Photographer, April 1989 FOUNDATION DETAIL REVEALED AS RESULT ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Everett Weinreb, Photographer, April 1989 FOUNDATION DETAIL REVEALED AS RESULT OF HOUSE DEMOLITION - Irvine Ranch Agricultural Headquarters, Boyd Tenant House, Southeast of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

Problems associated with nondestructive evaluation of bridges

DOT National Transportation Integrated Search

1995-06-01

The Orlando Metropolitan Area has a rich history in the development and deployment of intelligent Transportation Systems (ITS). Starting in 1990, the Florida Department of Transportation (FDOT) began development of a freeway surveillance system for l...

Guidelines for spacing between freeway ramps.

DOT National Transportation Integrated Search

2009-11-01

Existing geometric design guidance related to interchange ramp spacing in the Texas Roadway Design : Manual and the AASHTOs A Policy on Geometric Design of Highways and Streets (Green Book) is not : speed-dependent even though intuition indicates ...

Missouri Highway Safety Manual Recalibration

DOT National Transportation Integrated Search

2018-05-01

The Highway Safety Manual (HSM) is a national manual for analyzing the highway safety of various facilities, including rural roads, urban arterials, freeways, and intersections. The HSM was first published in 2010, and a 2014 supplement addressed fre...

Mining vehicle classifications from the Columbus Metropolitan Freeway Management System.

DOT National Transportation Integrated Search

2015-01-01

Vehicle classification data are used in many transportation applications, including: pavement design, : environmental impact studies, traffic control, and traffic safety. Ohio has over 200 permanent count stations, : supplemented by many more short-t...

Safety performance for freeway weaving segments.

DOT National Transportation Integrated Search

2014-09-01

The intensive lane change maneuvers at weaving sections often result in safety and operational problems. : Various factors, including the design of ramp roadways, use of auxiliary lanes, and continuity of lanes will have : significant effects on the ...

Costs and benefits of MDOT intelligent transportation system deployments.

DOT National Transportation Integrated Search

2015-07-01

This report analyses costs and benefits of Intelligent Transportation Systems (ITS) deployed by : the Michigan Department of Transportation (MDOT). MDOT ITS focuses on traffic incident : management and also provide Freeway Courtesy Patrol services. A...

Traffic detector handbook : third edition. Volume II

DOT National Transportation Integrated Search

2006-10-01

The objective of this Handbook is to provide a comprehensive resource for selecting, designing, installing, and maintaining traffic sensors for signalized intersections and freeways. It is intended for use by traffic engineers and technicians having ...

Freeway management and operations handbook

DOT National Transportation Integrated Search

1995-02-01

This paper: (1) describes current logistics practices as they are affected by truck size and weight limits; (2) examines how changes in truck size and weight limits might affect logistics practices; and (3) where possible, identifies research needed ...

Improving freight crash incident management.

DOT National Transportation Integrated Search

2015-06-01

The objective of this study was to determine the most effective way to mitigate the effect of freight : crash incidents on Louisiana freeways. Candidate incident management strategies were reviewed from : practice in other states and from those publi...

Neural network model for automatic traffic incident detection : executive summary.

DOT National Transportation Integrated Search

2001-04-01

Automatic freeway incident detection is an important component of advanced transportation management systems (ATMS) that provides information for emergency relief and traffic control and management purposes. In this research, a multi-paradigm intelli...

Guidelines for freeway lighting curfews.

DOT National Transportation Integrated Search

2012-10-01

Roadway lighting is provided on selected highways to improve the visibility of the nighttime environment. : Roadway lighting is typically warranted on the basis of the daily traffic volume. However, in the earlymorning : hours, the traffic volumes ma...

Enhancement of freeway incident traffic management and resulting benefits.

DOT National Transportation Integrated Search

2012-04-01

To improve traffic conditions on major highways plagued by non-recurrent congestion, most : highway agencies have invested their resources in two principal operational programs: incident response : and clearance, and traffic impact management. Howeve...

Houston North Freeway Contraflow Lane Demonstration.

DOT National Transportation Integrated Search

1982-12-01

On August 28, 1979, the Metropolitan Transit Authority (METRO) of Harris County in Texas, in cooperation with the Texas State Department of Highways and Public Transportation and the Urban Mass Transportation Administration, began operation of a cont...

Evaluation of Michigan's engineering improvements for older drivers.

DOT National Transportation Integrated Search

2015-09-01

In 2004, the Michigan Department of Transportation (MDOT) began a comprehensive program : to implement engineering countermeasures to address the needs of older drivers. The : countermeasures included the use of Clearview Font on Guide Signs (freeway...

Traffic detector handbook : third edition. Volume I

DOT National Transportation Integrated Search

2006-10-01

The objective of this Handbook is to provide a comprehensive resource for selecting, designing, installing, and maintaining traffic sensors for signalized intersections and freeways. It is intended for use by traffic engineers and technicians having ...

General guidelines for active traffic management deployment : interim report.

DOT National Transportation Integrated Search

2011-08-01

Continued growth in travel in congested freeway corridors and limited public funding for expansion and improvement projects are limiting agencies abilities to provide sufficient roadway capacity in major metropolitan areas. Focusing on trip reliab...

ITS data quality : assessment procedure for freeway point detectors.

DOT National Transportation Integrated Search

2003-01-01

The Virginia Department of Transportation (VDOT) has made significant investments in the traffic-monitoring infrastructure that supports intelligent transportation systems (ITS). The purpose of this infrastructure is to provide accurate, real-time in...

Incident management program for Virginia.

DOT National Transportation Integrated Search

1988-01-01

Freeways that are already operating at or near capacity are becoming more congested because of frequent incidents such as accidents, disabled vehicles, etc. In an effort to initiate an incident management program in Virginia, information from other s...

National Traffic Speeds Survey I : 2007

DOT National Transportation Integrated Search

2012-08-01

A field survey was conducted during spring and summer 2007 to measure travel speeds and prepare nationallyrepresentative : speed estimates for all types of motor vehicles on freeways, arterial highways, and collector roads : across the United States....

Evaluation of reference markers : final report.

DOT National Transportation Integrated Search

2001-06-01

The objective of this research evaluation was to evaluate the reference markers which were installed on sections of interstates and freeways in the Cincinnati-Northern Kentucky area, the Lexington-Fayette Urban County area, the Louisville-southern In...

Travlink Operational Test Evaluation Report; Final Report

DOT National Transportation Integrated Search

1996-08-01

">THE OBJECTIVES OF THE TRAVLINK OPERATIONAL TEST WERE TO IMPROVE TRANSIT FLEET MANAGEMENT, IMPROVE THE TIMELINESS AND ACCURACY OF TRAVEL INFORMATION, AND ENCOURAGE TRANSIT RIDERSHIP. THE PROJECT'S CORRIDOR WAS A NEWLY RECONSTRUCTED FREEWAY THAT WAS ...

Acceleration lane design for higher truck volumes.

DOT National Transportation Integrated Search

2008-12-09

The research project examined attributes associated with tractor-trailer trucks accelerating on freeway entry ramps and : entering the main traffic lanes. Data for this project were collected at five commercial vehicle weigh stations in : Arkansas an...

Crash location correction for freeway interchange modeling : research summary.

DOT National Transportation Integrated Search

2016-06-01

The project found that 69% of : all reviewed crashes were : landed incorrectly within the : interchange. The error rates by : facility type were 90% for : ramps, 79% for terminals, and : 53% for speed-change lanes.

Implementing active traffic management strategies in the U.S.

DOT National Transportation Integrated Search

2010-10-01

Limited public funding for roadway expansion and improvement projects, coupled with continued growth in travel along congested urban freeway corridors, creates a pressing need for innovative congestion management approaches. Strategies to address con...

Neural network model for automatic traffic incident detection : final report, August 2001.

DOT National Transportation Integrated Search

2001-08-01

Automatic freeway incident detection is an important component of advanced transportation management systems (ATMS) that provides information for emergency relief and traffic control and management purposes. In this research, a multi-paradigm intelli...

Evaluation of methods for freeway operational analysis.

DOT National Transportation Integrated Search

2001-10-01

The ability to estimate accurately the operational performance of roadway segments has become increasingly critical as we move from a period of new construction into one of operations, maintenance, and, in some cases, reconstruction. In addition to m...

Design and scope of impact of auxiliary lanes : technical report.

DOT National Transportation Integrated Search

2014-06-01

For decades, Texas Department of Transportation districts have constructed auxiliary lanes to support interchange : ramp operations and to resolve congestion proximate to freeway entrance and exit ramps. While auxiliary lanes are : built throughout T...

Dynamic Stochastic Control of Freeway Corridor Systems : Summary and Project Overview

DOT National Transportation Integrated Search

1978-12-01

Systematic methodological approaches to overall traffic management from both short-term (real-time) and long-term (planning) perspectives have been developed. The approach embodies formulation and solution of interrelated mathematical problems from o...

Investigation of freeway operations in metro Detroit.

DOT National Transportation Integrated Search

2011-10-01

Traffic incidents are the primary cause of non-recurrent congestion in urban areas, resulting in : reductions in roadway capacity due to crashes, vehicle breakdowns, and other events. In addition to : contributing to congestion and delay, incidents c...

Maine Facility Research Summary : Dynamic Sign Systems for Narrow Bridges

DOT National Transportation Integrated Search

1997-09-01

This report describes the development of operational surveillance data processing algorithms and software for application to urban freeway systems, conforming to a framework in which data processing is performed in stages: sensor malfunction detectio...

An optimization model for roadway pricing on rural freeways.

DOT National Transportation Integrated Search

2012-02-01

The main objective of rural roadway pricing is revenue generation, rather than elimination of congestion externalities. This report presents a model that provides optimum tolls accounting for pavement deterioration and economic impacts. This model co...

Demand based signal retiming phase 2 - real-world implementation.

DOT National Transportation Integrated Search

2015-11-01

Monitoring and managing arterial operations represents a significant problem for many public agencies in the : US. Arterial streets, more numerous and covering much larger road networks than freeways, get less attention : when it comes to deployment ...

Development and testing of operational incident detection algorithms : executive summary

DOT National Transportation Integrated Search

1997-09-01

This report describes the development of operational surveillance data processing algorithms and software for application to urban freeway systems, conforming to a framework in which data processing is performed in stages: sensor malfunction detectio...

Silicon Valley Smart Corridor : draft evaluation strategy

DOT National Transportation Integrated Search

2000-06-05

This document outlines the strategy for evaluating the integrated freeway, arterial, and incident management system known as the Silicon Valley Smart Corridor (SVSC). Centered in San Jose, California, the SVSC is one of approximately 65 deployments o...

Everett Weinreb, Photographer, April 1989 GARAGE BEHIND HOUSE, EAST (FRONT) ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Everett Weinreb, Photographer, April 1989 GARAGE BEHIND HOUSE, EAST (FRONT) AND WEST SIDE, LOOKING SOUTHEAST - Irvine Ranch Agricultural Headquarters, Boyd Tenant House, Southeast of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

TENANT HOUSE INTERIOR, KITCHEN, NORTH AND EAST WALLS, LOOKING NORTHEAST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

TENANT HOUSE INTERIOR, KITCHEN, NORTH AND EAST WALLS, LOOKING NORTHEAST FROM CENTER OF ROOM - Irvine Ranch Agricultural Headquarters, Carillo Tenant House, Southwest of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

TENANT HOUSE INTERIOR, LIVING ROOM, NORTH AND EAST WALLS, LOOKING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

TENANT HOUSE INTERIOR, LIVING ROOM, NORTH AND EAST WALLS, LOOKING NORTH FROM CENTER OF ROOM - Irvine Ranch Agricultural Headquarters, Carillo Tenant House, Southwest of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

TENANT HOUSE INTERIOR, KITCHEN, SOUTH AND EAST WALLS, LOOKING SOUTHEAST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

TENANT HOUSE INTERIOR, KITCHEN, SOUTH AND EAST WALLS, LOOKING SOUTHEAST FROM CENTER OF ROOM - Irvine Ranch Agricultural Headquarters, Carillo Tenant House, Southwest of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

TENANT HOUSE INTERIOR, LIVING ROOM, SOUTH AND EAST WALLS, LOOKING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

TENANT HOUSE INTERIOR, LIVING ROOM, SOUTH AND EAST WALLS, LOOKING SOUTHEAST FROM CENTER OF ROOM - Irvine Ranch Agricultural Headquarters, Carillo Tenant House, Southwest of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

Highway bridges in the United States--an overview

DOT National Transportation Integrated Search

2007-09-01

Bridges are an integral part of the U.S. highway network, providing links across natural barriers, passage over railroads and highways, and freeway connections. The Federal Highway Administration (FHWA) maintains a database of our nations highway ...

SOUTHERN CALIFORNIA PARTICLE CENTER (SCPC)

EPA Science Inventory

The research proposed by the SCPC will provide extensive characterization of chemical composition, activity, and toxicological potential of a wide variety of ambient PM, including samples collected at freeways, air and sea ports, indoors and outdoors under varying climatologic...

Evaluation of Incident Detection Methodologies

DOT National Transportation Integrated Search

1999-10-01

Original Report Date: October 1998. The detection of freeway incidents is an essential element of an area's traffic management system. Incidents need to be detected and handled as promptly as possible to minimize delay to the public. Various algorith...

Speed harmonization and peak-period shoulder use to manage urban freeway congestion.

DOT National Transportation Integrated Search

2009-10-01

Traffic congestion is an increasing problem in the nations urban areas, leading to personal inconvenience, : increased pollution, hampered economic productivity, and reduced quality of life. While traffic congestion tends : to continuously increas...

Metropolitan Model Deployment Initiative/ATIS Symposium : notes

DOT National Transportation Integrated Search

2000-02-01

The Symposium focuses on ATIS from the MMDIs investment in traveler information and integration. Infrastructure should be in place from the MMDIs for an interest in a regional multi-modal traveler information with the major arterials, freeways ...

I-87/US 9 integrated corridor management plan.

DOT National Transportation Integrated Search

2015-11-01

This study evaluates the potentiality of developing an integrated freeway / arterial corridor : plan to improve overall operations of I-87 and US 9 (parallel arterial) by improving the methodology of : addressing recurring and non-recurring delays (i...

Length based vehicle classification on freeways from single loop detectors.

DOT National Transportation Integrated Search

2009-10-15

Roadway usage, particularly by large vehicles, is one of the fundamental factors determining the lifespan : of highway infrastructure, e.g., as evidenced by the federally mandated Highway Performance : Monitoring System (HPMS). But the complexity of ...

Simulation of Automated Vehicles' Drive Cycles

DOT National Transportation Integrated Search

2018-02-28

This research has two objectives: 1) To develop algorithms for plausible and legally-justifiable freeway car-following and arterial-street gap acceptance driving behavior for AVs 2) To implement these algorithms on a representative road network, in o...

Analysis of design attributes and crashes on the Oregon highway system : final report.

DOT National Transportation Integrated Search

2001-08-01

This report has investigated the statistical relationship between crash activity and roadway design attributes on the Oregon state : highway system. Crash models were estimated from highway segments distinguished by functional classification (freeway...

Investigating the effect of freeway congestion thresholds on decision-making inputs.

DOT National Transportation Integrated Search

2010-05-01

Congestion threshold is embedded in the congestion definition. Two basic approaches exist in : current practice for setting the congestion threshold. One common approach uses the free-flow or : unimpeded conditions as the congestion threshold. ...

Bluetooth-based travel time/speed measuring systems development.

DOT National Transportation Integrated Search

2010-06-01

Agencies in the Houston region have traditionally used toll tag readers to provide travel times on : freeways and High Occupancy Vehicle (HOV) lanes, but these systems require large amounts of costly and : physically invasive infrastructure. Bluetoot...

Comparison of methods for measuring travel time at Florida freeways and arterials : [summary].

DOT National Transportation Integrated Search

2014-07-01

In this project, University of Florida researchers : collected field data along several highways to : evaluate travel time measurements from several : sources: STEWARD, BlueTOAD, INRIX, and HERE. : STEWARD (Statewide Transportation Engineering : Ware...

Forterra Concrete Products, Inc.

EPA Pesticide Factsheets

The EPA is providing notice of a proposed Administrative Penalty Assessment against Forterra Concrete Products, Inc., a business located at 511 E. John Carpenter Freeway, Irving, TX, 75062, for alleged violations at its facility located at 23600 W. 40th St

Improved chain control operations.

DOT National Transportation Integrated Search

2010-01-01

In California, field maintenance personnel use turntable signs to advise motorists of chain control conditions on rural : highways and freeways. To do this an operator has to park, exit the vehicle, turn the sign on the shoulder and then : walk acros...

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...

State Route 60 automated truck facility.

DOT National Transportation Integrated Search

2008-01-01

A research was conducted to evaluate a dedicated automated truck lane along a case study route 60 (Pomona : Freeway) to accommodate higher truck volume using AHS technologies and to estimate the associated costs of : such technologies. A cost analysi...

Business losses, transportation damage and the Northridge Earthquake

DOT National Transportation Integrated Search

1998-05-01

The 1994 Northridge earthquake damaged four major freeways in the Los Angeles area. Southern California firms were surveyed to assess the role that these transportation disruptions played in business losses. Of the firms that reported any earthquake ...

Silicon Valley Smart Corridor : final evaluation report

DOT National Transportation Integrated Search

2003-08-01

This document summarizes the findings from the evaluation of the integrated freeway, arterial, and incident management system known as the Silicon Valley Smart Corridor (SVSC). Centered along the Highway 17/Interstate 880 corridor in San Jose, Califo...

Traffic prediction using wireless cellular networks : final report.

DOT National Transportation Integrated Search

2016-03-01

The major objective of this project is to obtain traffic information from existing wireless : infrastructure. : In this project freeway traffic is identified and modeled using data obtained from existing : wireless cellular networks. Most of the prev...

Mining vehicle classifications from the Columbus Metropolitan Freeway Management System : [summary].

DOT National Transportation Integrated Search

2015-01-01

Vehicle classification data are used in many transportation applications, including: pavement design, : environmental impact studies, traffic control, and traffic safety. Ohio has over 200 permanent count : stations, supplemented by many more short-t...

Telecommunications handbook for transportation professionals : the basics of telecommunications.

DOT National Transportation Integrated Search

2004-08-01

This handbook was created to provide individuals responsible for managing and implementing Traffic : Signal, and Freeway Management programs with an understand of the basic technologies of : telecommunications. The handbook provides a brief look at t...

Low Cost Wireless Network Camera Sensors for Traffic Monitoring

DOT National Transportation Integrated Search

2012-07-01

Many freeways and arterials in major cities in Texas are presently equipped with video detection cameras to : collect data and help in traffic/incident management. In this study, carefully controlled experiments determined : the throughput and output...

Best practices and outreach for active traffic management : final report.

DOT National Transportation Integrated Search

2011-12-01

Continued growth in travel on congested freeway corridors and limited public funding for : expansion and improvement projects are limiting agencies abilities to provide sufficient roadway : capacity in major metropolitan areas. Focusing on trip re...

Assessing the performance of the SpeedInfo sensor.

DOT National Transportation Integrated Search

2013-12-01

Until recently freeway traffic operations data were collected in house by the Ohio Department of : Transportation (ODOT) using loop detectors. In recent years several private companies have emerged with a : viable opportunity to outsource traffic dat...

Modeling of dispersion near roadways based on the vehicle-induced turbulence concept

NASA Astrophysics Data System (ADS)

Sahlodin, Ali M.; Sotudeh-Gharebagh, Rahmat; Zhu, Yifang

A mathematical model is developed for dispersion near roadways by incorporating vehicle-induced turbulence (VIT) into Gaussian dispersion modeling using computational fluid dynamics (CFD). The model is based on the Gaussian plume equation in which roadway is regarded as a series of point sources. The Gaussian dispersion parameters are modified by simulation of the roadway using CFD in order to evaluate turbulent kinetic energy (TKE) as a measure of VIT. The model was evaluated against experimental carbon monoxide concentrations downwind of two major freeways reported in the literature. Good agreements were achieved between model results and the literature data. A significant difference was observed between the model results with and without considering VIT. The difference is rather high for data very close to the freeways. This model, after evaluation with additional data, may be used as a framework for predicting dispersion and deposition from any roadway for different traffic (vehicle type and speed) conditions.

Highway planning and operations for the Dallas district: Implementation and evaluation of concurrent flow HOV lanes in Texas. Research report, September 1996--August 1997

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

Skowronek, D.A.; Stoddard, A.M.; Ranft, S.E.

1997-11-01

Limited capital investment for major transportation improvements and growth in metropolitan areas require the most efficient use of the existing transportation system. One means to achieve this is high-occupancy vehicle (HOV) lanes. While an extensive system of permanent HOV lanes is planned for the Dallas-Fort Worth urbanized area, the Texas Department of Transportation (TxDOT) and Dallas Area Rapid Transit (DART) have pursued and continue short-term or interim HOV lane projects that would enhance public transportation and overall mobility. There are currently 57 km (35.4 mi) of interim HOV lanes operational in the Dallas area, including a barrier-separated contraflow lane onmore » I-30 (East R.L. Thornton Freeway) and buffer-separated concurrent flow HOV lanes on I-35E North (Stemmons Freeway) and I-635 (Lyndon B. Johnson Freeway). The objective of this research is to investigate the operational effectiveness of the new concurrent flow HOV lanes in the Dallas area, as well as to assess the effectiveness of concurrent flow (buffer-separated) versus contraflow (barrier-separated) HOV lanes. Issues such as person movement, carpool formation, travel time savings, violation rates, and project cost effectiveness are addressed. By understanding the operational performance and issues of both concurrent flow (buffer-separated) HOV lanes and contraflow (barrier-separated) HOV lanes, recommendations can be made on suggested HOV lane polices, including the type of permanent HOV lanes to be implemented in the Dallas area.« less

Freeway operations analysis of I-80 to I-29 interchange.

DOT National Transportation Integrated Search

1974-01-01

At the request of the Iowa State Highway Commission, the Engineering Research Institute observed the traffic operations at the Interstate 29 (1-29) and Interstate 80 (1-80) interchange in the southwest part of Council Bluffs.

Incorporating ITS into transportation planning : phase 1 final report

DOT National Transportation Integrated Search

2000-04-01

Incident management is the process of managing multi-agency, multi-jurisdictional responses to highway traffic disruptions. Traffic incidents are a major cause of congestion on the nation?s highway network. More than half of all freeway traffic conge...

Model regulations and public education for rural-suburban pedestrian safety

DOT National Transportation Integrated Search

1980-08-01

The objectives of this study were to review the rural-suburban pedestrian accident data (Knoblauch, 1977) and freeway pedestrian accident data (Knoblauch, Moore and Schmitz, 1976) and determine which accident types were amenable to countermeasures de...

Performance of alternative diamond interchange forms : volume I -- research report.

DOT National Transportation Integrated Search

2017-01-01

Service interchanges connect freeways to arterial roads and are the backbone of the U.S. road network. Improving the operations of service interchanges is possible by applying one of several new solutions: diverging diamond, single point interchanges...

I-880 field experiment : analysis of incident data.

DOT National Transportation Integrated Search

1997-01-01

The I-880 field experiment has produced one of the largest data bases on incidents and freeway traffic-flow characteristics ever compiled. Field data on incidents were collected through observations of probe-vehicle drivers before and after the imple...

RHODES-ITMS-MILOS : ramp metering system test

DOT National Transportation Integrated Search

2002-04-01

The RHODES-Integrated Traffic Management System Program addresses the design and development of a real-time traffic adaptive control system for an integrated system of freeways and arterial roads. The goals of this project were to test coordinated, a...

Everett Weinreb, Photographer, April 1989 GARAGE BEHIND HOUSE, SOUTH SIDE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Everett Weinreb, Photographer, April 1989 GARAGE BEHIND HOUSE, SOUTH SIDE AND WEST (REAR) FACADES, LOOKING NORTHEAST - Irvine Ranch Agricultural Headquarters, Boyd Tenant House, Southeast of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

Use of advanced analysis tools to support freeway corridor freight planning.

DOT National Transportation Integrated Search

2010-07-22

Advanced corridor freight management and pricing strategies are increasingly being chosen to : address freight mobility challenges. As a result, evaluation tools are needed to assess the benefits : of these strategies as compared to other alternative...

Meeting Environmental Requirements after a Bridge Collapse

DOT National Transportation Integrated Search

2000-11-01

This document is an update to the Freeway Incident Management Handbook, published in 1991 by the FHWA. It provides detail on important elements of successful incident management programs, as well as field operations. It includes new and advanced inci...

NCDOT level of service software program for highway capacity manual planning applications.

DOT National Transportation Integrated Search

2006-08-01

The Transportation Planning Branch (TPB) of the North Carolina Department of Transportation (NCDOT) desired a : user-friendly tool for determining highway capacity and service volumes for freeways, multilane highways, arterials, and : two-lane highwa...

Reduced lighting on freeways during periods of low traffic density

DOT National Transportation Integrated Search

1995-02-01

Geometry-related effects of changes in truck size and weight regulations include a diverse set of highway design elements related to virtually every aspect of vehicle design and operation. The turning, stopping, acceleration, hill-climbing, and other...

Study of high-tension cable barriers on Michigan roadways.

DOT National Transportation Integrated Search

2014-10-01

Median-crossover crashes present the highest risk of fatality and severe injury among all collision types on : freeways. These crashes are caused by : a variety of factors, including drowsiness, driver distraction, impaired : driving, and loss of con...

Comparison of methods for measuring travel time at Florida freeways and arterials.

DOT National Transportation Integrated Search

2014-07-01

Travel time is an important performance measure used to assess the traffic operational quality of various types of highway : facilities. Previous research funded by the Florida Department of Transportation (FDOT) on travel time reliability developed,...

Performance evaluation of cable median barrier systems in Texas.

DOT National Transportation Integrated Search

2009-08-01

Since 2003, the Texas Department of Transportation (TxDOT) has embarked on an aggressive campaign to install : median barriers to prevent cross-median crashes on freeway facilities statewide. In the few years prior to 2003, : virtually all fatalities...

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...

Development of a MASH TL-3 median barrier gate.

DOT National Transportation Integrated Search

2011-06-01

Median barriers are commonly used to separate opposing lanes of traffic on divided highways and to : separate managed lanes from general purpose lanes. Concrete median barriers (CMBs) are often preferred : on urban freeways with narrow medians due to...

Mobile platform for overhead detectors of road vehicles.

DOT National Transportation Integrated Search

2002-06-01

The California Department of Transportation (CALTRANS) has a need to monitor traffic flow over freeways. Currently, this is done mainly : through the use of loop detectors. These are measuring devices that are buried under the road pavement, an...

Estimation of Traffic Variables Using Point Processing Techniques

DOT National Transportation Integrated Search

1978-05-01

An alternative approach to estimating aggregate traffic variables on freeways--spatial mean velocity and density--is presented. Vehicle arrival times at a given location on a roadway, typically a presence detector, are regarded as a point or counting...

Applications for the environment : real-time information synthesis (AERIS). Eco-lanes : operational concept.

DOT National Transportation Integrated Search

2013-10-01

This document serves as an Operational Concept for the Applications for the Environment: Real-Time Information Synthesis (AERIS) Eco-Lanes Transformative Concept. The Eco-Lanes Transformative Concept features dedicated lanes on freeways optimized for...

Congestion-Responsive On-Ramp Metering : Before and After Studies - Phase 1

DOT National Transportation Integrated Search

2016-07-06

The objective of this project was to develop recommendations toward a statewide policy of congestion responsive freeway ramp metering operation. The research is performed in two phases. In phase 1, alternative ramp metering activation strategies were...

Application of bluetooth technology to rural freeway speed data collection.

DOT National Transportation Integrated Search

2012-10-01

Bluetooth data collection devices are an innovative technique for measuring travel times and speeds on roadway segments. This project developed a system capable of recording Bluetooth MAC addresses with a timestamp and determining the space mean spee...

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...

Propagation of Disturbances in Traffic Flow

DOT National Transportation Integrated Search

1977-09-01

The system-optimized static traffic-assignment problem in a freeway corridor network is the problem of choosing a distribution of vehicles in the network to minimize average travel time. It is of interest to know how sensitive the optimal steady-stat...

Freeway Traffic Flow Following a Lane Blockage

DOT National Transportation Integrated Search

1996-07-01

As part of the assessment of the development and deployment of ITS products and services in metropolitan areas sponsored by the U.S. Department of Transportations (U.S. DOT) Joint Program Office for ITS, analysts from the Volpe National Transporta...

Evaluation of optimal traffic monitoring station spacing on freeways.

DOT National Transportation Integrated Search

2009-02-01

Results showed that UDOT can reduce the number of detectors currently maintained by TMCs and can deploy far fewer than the mile spacing guidelines. This should result in significant cost savings in capital, operations, and maintenance costs. Fu...

Automated low-cost and real-time truck parking information system : [research summary].

DOT National Transportation Integrated Search

2013-11-01

Overnight truck parking is a significant safety problem nationwide. Commercial drivers : seeking to comply with the Federal Motor Carrier Safety Administrations Hours of : Service regulations often park illegally on freeway shoulders and ramps whe...

Particle count and black carbon measurements at schools in Las Vegas, NV and in the greater Salt Lake City, UT area.

PubMed

Brown, Steven G; Vaughn, David L; Roberts, Paul T

2017-11-01

As part of two separate studies aimed to characterize ambient pollutant concentrations at schools in urban areas, we compare black carbon and particle count measurements at Adcock Elementary in Las Vegas, NV (April-June 2013), and Hunter High School in the West Valley City area of greater Salt Lake City, UT (February 2012). Both schools are in urban environments, but Adcock Elementary is next to the U.S. 95 freeway. Black carbon (BC) concentrations were 13% higher at Adcock compared to Hunter, while particle count concentrations were 60% higher. When wind speeds were low-less than 2 m/sec-both BC and particle count concentrations were significantly higher at Adcock, while concentrations at Hunter did not have as strong a variation with wind speed. When wind speeds were less than 2 m/sec, emissions from the adjacent freeway greatly affected concentrations at Adcock, regardless of wind direction. At both sites, BC and particle count concentrations peaked in the morning during commute hours. At Adcock, particle count also peaked during midday or early afternoon, when BC was low and conditions were conducive to new particle formation. While this midday peak occurred at Adcock on roughly 45% of the measured days, it occurred on only about 25% of the days at Hunter, since conditions for particle formation (higher solar radiation, lower wind speeds, lower relative humidity) were more conducive at Adcock. Thus, children attending these schools are likely to be exposed to pollution peaks during school drop-off in the morning, when BC and particle count concentrations peak, and often again during lunchtime recess when particle count peaks again. Particle count concentrations at two schools were shown to typically be independent of BC or other pollutants. At a school in close proximity to a major freeway, particle count concentrations were high during the midday and when wind speeds were low, regardless of wind direction, showing a large area of effect from roadway emissions even when the school was not downwind of the roadway. At the second school, which sits in an urban neighborhood away from freeways, high particle counts occurred even though solar radiation was low during wintertime conditions, meaning that exposure to high particle counts can occur throughout the year.

Work zone safety analysis and modeling: a state-of-the-art review.

PubMed

Yang, Hong; Ozbay, Kaan; Ozturk, Ozgur; Xie, Kun

2015-01-01

Work zone safety is one of the top priorities for transportation agencies. In recent years, a considerable volume of research has sought to determine work zone crash characteristics and causal factors. Unlike other non-work zone-related safety studies (on both crash frequency and severity), there has not yet been a comprehensive review and assessment of methodological approaches for work zone safety. To address this deficit, this article aims to provide a comprehensive review of the existing extensive research efforts focused on work zone crash-related analysis and modeling, in the hopes of providing researchers and practitioners with a complete overview. Relevant literature published in the last 5 decades was retrieved from the National Work Zone Crash Information Clearinghouse and the Transport Research International Documentation database and other public digital libraries and search engines. Both peer-reviewed publications and research reports were obtained. Each study was carefully reviewed, and those that focused on either work zone crash data analysis or work zone safety modeling were identified. The most relevant studies are specifically examined and discussed in the article. The identified studies were carefully synthesized to understand the state of knowledge on work zone safety. Agreement and inconsistency regarding the characteristics of the work zone crashes discussed in the descriptive studies were summarized. Progress and issues about the current practices on work zone crash frequency and severity modeling are also explored and discussed. The challenges facing work zone safety research are then presented. The synthesis of the literature suggests that the presence of a work zone is likely to increase the crash rate. Crashes are not uniformly distributed within work zones and rear-end crashes are the most prevalent type of crashes in work zones. There was no across-the-board agreement among numerous papers reviewed on the relationship between work zone crashes and other factors such as time, weather, victim severity, traffic control devices, and facility types. Moreover, both work zone crash frequency and severity models still rely on relatively simple modeling techniques and approaches. In addition, work zone data limitations have caused a number of challenges in analyzing and modeling work zone safety. Additional efforts on data collection, developing a systematic data analysis framework, and using more advanced modeling approaches are suggested as future research tasks.

Evaluation of non-freeway rumble strips - phase II.

DOT National Transportation Integrated Search

2015-03-01

MDOTs rumble strip program for two-lane high speed rural highways was initiated in 2008 and : continued through 2010. This program included implementation of centerline rumble strips (CLRS) : on nearly 5,400 miles of two-lane high speed roads that...

Using detector data to identify and examine crashes and incidents on freeways.

DOT National Transportation Integrated Search

2010-09-01

Traffic incidents, such as crashes and vehicular breakdowns, result in reductions in roadway capacity and : are the primary cause of non-recurrent congestion in urban areas. In addition to contributing to : congestion and delay, incidents adversely a...

Using detector data to identify and examine crashes and incidents on freeways

DOT National Transportation Integrated Search

2010-09-01

Traffic incidents, such as crashes and vehicular breakdowns, result in reductions in roadway capacity and are the primary cause of non-recurrent congestion in urban areas. In addition to contributing to congestion and delay, incidents adversely affec...

The Recreational Pilot Practical Test Standard for Powered Parachute

DOT National Transportation Integrated Search

1997-06-01

The I-4 Surveillance and Motorist Information System (SMIS) in the Orlando metropolitan area is Florida's largest existing Freeway Management System (FMS). This system was initially installed in 1991 (Phase I) to help support the TravTek ITS Operatio...

Evaluating the benefits of dynamic message signs on Missouri's rural corridors.

DOT National Transportation Integrated Search

2011-12-01

Dynamic message signs (DMSs) are traffic control devices that provide real-time traveler information and are used for traffic warning, regulation, routing and management. DMSs on freeways in rural areas in southeast Missouri were evaluated. First, mo...

Performance analysis of Virginia's safety service patrol programs : a case study approach.

DOT National Transportation Integrated Search

2006-01-01

Many state departments of transportation (DOTs) operate safety service patrols (SSPs) as part of their incident management programs. The primary objectives of SSPs are to minimize the duration of freeway incidents, restore full capacity of the freewa...

DIVERT (during incidents vehicles exit to reduce time) : evaluation report

DOT National Transportation Integrated Search

1998-09-01

The goal of DIVERT is to provide management strategies during periods of freeway incidents by routing diverted traffic over city surface arterials in a planned, coordinated manner. Several detailed findings of the evaluation of this project are inclu...

Quantifying the impact of large percent trucks proportion on rural freeways.

DOT National Transportation Integrated Search

2014-02-01

The trucking industry continues to contribute significantly to the economy of the United States. : The surface transportation system has been a critical component for the movement of goods and : services by the trucking industry across the country. R...

ITS impacts assessment for Seattle MMDI evaluation : modeling methodology and results

DOT National Transportation Integrated Search

1999-01-01

This document presents a modeling analysis of Intelligent Transportation Systems (ITS) impacts from the SmartTrek program in Seattle, Washington. This report describes the methodology of the study and presents the finding for a mixed freeway/arterial...

Roadway network productivity assessment : system-wide analysis under variant travel demand

DOT National Transportation Integrated Search

2008-11-01

The analysis documented in this report examines the hypothesis that the system-wide productivity of a metropolitan freeway system in peak periods is higher in moderate travel demand conditions than in excessive travel demand conditions. The approach ...

Perspective View, Landsat Overlay Pasadena, California

NASA Image and Video Library

2000-02-21

This image shows a perspective view of the area around Pasadena, California, just north of Los Angeles. The cluster of hills surrounded by freeways on the left is the Verdugo Hills, which lie between the San Gabriel Valley and the San Fernando Valley.

Applying systems engineering principles to the development of transportation communication standards.

DOT National Transportation Integrated Search

2011-04-22

Using traffic control devices and communications equipment to monitor and control arterials and freeways has brought with it new challenges and a demand for new skills to the transportation industry. Some of the challenges include integrating informa...

Information on estimating local government highway bonds

DOT National Transportation Integrated Search

1973-06-01

The theory of traffic flow following a lane blockage on a multi-lane freeway has been developed. Numerical results have been obtained and are presented both for the steady state case where the traffic density remains constant and the non-steady state...

Assessing Feasibility of Priority Operations on Highways

DOT National Transportation Integrated Search

1973-05-01

This study was carried out as part of the BALANCE bus-priority-system evaluation. The objective of this study was to estimate the improvement in freeway passenger flow resulting from the reservation of priority lanes for buses and carpools. These est...

Direct, Operational Field Test Evaluation, Human Factors

DOT National Transportation Integrated Search

1998-08-01

IN THIS EXPERIMENT, 32 LICENSED DRIVERS (16 YOUNG, 16 OLD) DROVE ON AN EXPRESSWAY. ON EACH TRIAL (96 PER SUBJECT), 1 TO 3 TRAFFIC MESSAGES CONTAINING 6 TO 14 ITEMS WERE PRESENTED. (L-94 EASTBOUND AT SOUTHFIELD FREEWAY, CONTINUING CONSTRUCTION, RIGHT ...

Evaluating Environmental Impact of Traffic Congestion in Real Time Based on Sparse Mobile Crowd-sourced Data

DOT National Transportation Integrated Search

2018-02-02

Traffic congestion at arterial intersections and freeway bottlenecks degrades the air quality and threatens the public health. Conventionally, air pollutants are monitored by sparsely-distributed Quality Assurance Air Monitoring Sites. Sparse mobile ...

Improving truck and speed data using paired video and single-loop sensors

DOT National Transportation Integrated Search

2006-12-01

Real-time speed and truck data are important inputs for modern freeway traffic control and : management systems. However, these data are not directly measurable by single-loop detectors. : Although dual-loop detectors provide speeds and classified ve...

Guidelines for reducing wrong-way crashes on freeways.

DOT National Transportation Integrated Search

2014-05-01

Each year, hundreds of fatal wrong-way driving (WWD) crashes occur across the United States, and thousands : of injuries are reported in traffic crashes caused by wrong-way drivers. Although WWD crashes have been a : concern since the advent of acces...

Development of a statewide online system for traffic data quality control and sharing.

DOT National Transportation Integrated Search

2009-12-01

The Washington State Department of Transportation (WSDOT) operates thousands of Inductive Loop : Detectors (ILDs) on the freeways and highways of Washington State. The collection and disbursement of : this data is handled at the regional level, which...

Dynamic mobility applications policy analysis : policy and institutional issues for intelligent network flow optimization (INFLO).

DOT National Transportation Integrated Search

2014-12-01

The report documents policy considerations for the Intelligent Network Flow Optimization (INFLO) connected vehicle applications bundle. INFLO aims to optimize network flow on freeways and arterials by informing motorists of existing and impendi...

Project #8, Task 2 - Travel Information Services (TIS), Definition Of Goals For The I-95 Corridor

DOT National Transportation Integrated Search

1995-01-23

CONTINUED FROM DOCUMENT NUMBER 6303 : RESEARCH AND DEVELOPMENT OR R&D, ELECTRONIC PAYMENT SYSTEMS, AUTOMATED FARE COLLECTION, EMERGENCY MANAGEMENT SERVICES OR EMS, FREEWAY MANAGEMENT SYSTEMS, INCIDENT MANAGEMENT/INCIDENT DETECTION : THE L-95 CORRI...

Suggested Procedures For Evaluating The Effectiveness Of Freeway Hov Facilities

DOT National Transportation Integrated Search

1991-02-01

THIS REPORT PRESENTS THE RESULTS OF THE STATE-OF-THE-ART REVIEW OF EVALUATION PRACTICES USED WITH DIFFERENT HIGH-OCCUPANCY VEHICLE (HOV) LANE PROJECTS IN NORTH AMERICA. BASED ON THIS REVIEW, SUGGESTED PROCEDURES ARE OUTLINED FOR CONDUCTING BEFORE-AND...

Development of decision support systems for real-time freeway traffic routing : volume II.

DOT National Transportation Integrated Search

1998-01-01

Real-time traffic flow routing is a promising approach to alleviating congestion. Existing approaches to developing real-time routing strategies, however, have limitations. This study explored the potential for using case-based reasoning (CBR), an em...

An investigation of older driver freeway needs and capabilities : summary report

DOT National Transportation Integrated Search

1998-11-01

Limited-access highways and the Interstate highway system have been largely responsible for greatly increasing the mobility and safety enjoyed by the American driving population. However, as the driving population ages, it is not known if the require...

Evaluation of freeway motorist assist : staff summary, February 2010.

DOT National Transportation Integrated Search

2010-02-01

This research document builds on the previous Return on Investment (ROI) Study of Motorist Assist (1994) that evaluated the St. Louis Motor Assist program to establish and update current benefits of this program. The following is a summary of finding...

Development of guidelines for cable median barrier systems in Texas.

DOT National Transportation Integrated Search

2009-12-01

Since 2003, the Texas Department of Transportation (TxDOT) has embarked on an aggressive campaign to install : median barriers to prevent cross-median crashes on freeway facilities statewide. In the few years prior to 2003, : virtually all fatalities...

Highway planning and operations for the Dallas district : freeway system plan methodology : summary

DOT National Transportation Integrated Search

1997-11-01

The System Planning Methodology was developed jointly by the Texas Department of Transportation (TxDOT), North Central Texas Council of Governments (NCTCOG), Dallas Area Rapid Transit (DART), and Texas Transportation Institute (TTI) as a transportati...

Identifying chronic errors at freeway loop detectors- splashover, pulse breakup, and sensitivity settings.

DOT National Transportation Integrated Search

2011-03-01

Traffic Management applications such as ramp metering, incident detection, travel time prediction, and vehicle : classification greatly depend on the accuracy of data collected from inductive loop detectors, but these data are : prone to various erro...

HOV Project Case Studies, History and Institutional Arrangements

DOT National Transportation Integrated Search

1990-12-01

The Texas Transportation Institute (TTI), a part of The Texas A&M University : System, is conducting an assessment of high-occupancy vehicle (HOV) projects : located either on freeways or in separate rights-of-way in North America. The : three-year r...

Technology scan of future traveler information systems and applications in Georgia.

DOT National Transportation Integrated Search

2013-10-01

Statewide traveler information provided in Georgia through its NaviGAtor/5-1-1 system is : primarily based on Intelligent Transportation Systems (ITS) related to freeway traffic : management. The purpose of this study is to evaluate traveler informat...

Simulation analysis of route diversion strategies for freeway incident management : final report.

DOT National Transportation Integrated Search

1995-02-01

The purpose of this project was to investigate whether simulation models could : be used as decision aids for defining traffic diversion strategies for effective : incident management. A methodology was developed for using such a model to : determine...

Environmental Assessment of the City of El Cerrito, CA: Creek, Trash and Air Quality Analysis

NASA Astrophysics Data System (ADS)

Moore, A.; Ilan, A.

2015-12-01

The City of El Cerrito, CA is located within Western Contra Costa County and adjacent to the San Francisco Bay. Local land-uses that affect its overall public and environmental health include major freeways, railways, and commercial and industrial zones. In an effort to assess the overall health of the local environment, students at Korematsu Middle School conducted a comprehensive analysis that included street litter auditing, water monitoring of Cerritos Creek and air quality measurements made along local streets. In 2014 the City of El Cerrito adopted a long-term trash plan that included strategies for reducing trash loads of local stormwater sewer systems. This plan called for load reduction of 70% by July 1, 2017 and 100% by July 1, 2022. To evaluate the effectiveness of the trash plan, our team quantified and scored trash concentration levels at two locations—one in a residential neighborhood and the other in a commercial zone. We also monitored water quality at nearby Cerritos Creek to investigate the impacts that each area's trash concentrations had on water quality. We also monitored particulate matter (PM) concentration levels in air within these locations to determine whether or not differences exist between residential and commercial areas. Preliminary analysis of litter data suggests that the Long Term Trash Plan has thus far been effective in reducing concentrations of street litter along San Pablo Avenue, which is located within a major commercial zone, but has been inadequate in reducing trash in nearby parks. Water quality results indicate that Cerritos Creek contains waters that are quite healthy with respect to Ammonia and Nitrate concentration levels (i.e., very low values for every sample collected). However, elevated concentration levels of Phosphates were detected in every sample collected. Air quality data surprisingly revealed that extremely high PM concentration levels occur in air surrounding a residential park in El Cerrito.

LITERATURE FORENSICS: NAVIGATING THROUGH FLOTSAM, JETSAM, AND LAGAN

EPA Science Inventory

Intimidation and bewilderment are but two feelings scientists often confront when facing the ever- expanding universe of the published scientific literature. With the birth of any hypothesis, all fantasies of a one-way freeway for a scientific endeavor evaporate when the journey ...

Review of literature and practices for incident management programs : technical report.

DOT National Transportation Integrated Search

2016-06-01

The project team examined project evaluations, best practice summaries, and synthesis documents, and derived a summary of key elements of programs to speed the time to find and clear stalled vehicles and crashes from freeway shoulders and main lanes....

Brooks Grease Service, Inc. - Clean Water Act Public Notice

EPA Pesticide Factsheets

The EPA is providing notice of a proposed Administrative Penalty Assessment against Forterra Concrete Products, Inc., a business located at 511 E. John Carpenter Freeway, Irving, TX, 75062, for alleged violations at its facility located at 23600 W. 40th St

Development and testing of incident detection algorithms. Vol. 2, research methodology and detailed results.

DOT National Transportation Integrated Search

1976-04-01

The development and testing of incident detection algorithms was based on Los Angeles and Minneapolis freeway surveillance data. Algorithms considered were based on times series and pattern recognition techniques. Attention was given to the effects o...

User-friendly traffic incident management (TIM) program benefit-cost estimation tool, Version 1.2

DOT National Transportation Integrated Search

2016-01-01

Traffic incidents contribute significantly to the deterioration of the level of service of both freeways and arterials. Traffic Incident Management (TIM) programs have been introduced worldwide with the aim of mitigating the impact of traffic inciden...

Photocopy of photograph (original negative in possession of LSA Associates, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Photocopy of photograph (original negative in possession of LSA Associates, Irvine, California) Dana Privett, Photographer, August 1982 WEST (REAR), LOOKING EAST - Irvine Ranch Agricultural Headquarters, Boyd Tenant House, Southeast of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

Photocopy of photograph (original negative in possession of LSA Associates, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Photocopy of photograph (original negative in possession of LSA Associates, Irvine, California) Dana Privett, Photographer, August 1982 EAST (FRONT), LOOKING WEST - Irvine Ranch Agricultural Headquarters, Boyd Tenant House, Southeast of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

Improved guidelines for estimating the Highway safety manual calibration factors.

DOT National Transportation Integrated Search

2016-01-01

Crash prediction models can be used to predict the number of crashes and evaluate roadway safety. Part C of the first edition of the Highway Safety Manual (HSM) provides safety performance functions (SPFs). The HSM addendum that includes freeway and ...

Mobility and safety impacts of winter storm events in a freeway environment.

DOT National Transportation Integrated Search

2000-02-01

Several factors influence a driver's decision to travel, choice of vehicle speed, and the safety of a particular trip. These factors include, among others, the trip purpose, time of day, traffic volumes, weather and roadway conditions, and the range ...

Analysis of driver merging behavior at lane drops on freeways.

DOT National Transportation Integrated Search

2013-12-01

Lane changing assistance systems advise drivers on safe gaps for making mandatory lane changes at lane drops. In this : study, such a system was developed using a Bayes classifier and a decision tree to model lane changes. Detailed vehicle : trajecto...

Storm water monitoring along loop 202 and Salt River.

DOT National Transportation Integrated Search

2010-10-01

A comprehensive research program for the characterization of storm water runoff from an Arizona : highway was conducted from January through December 2007. The study area covered a portion of : the Loop 202 freeway west of Mesa Drive to a retention b...

Examination of fundamental traffic characteristics and implications to ITS

DOT National Transportation Integrated Search

1998-01-01

The purpose of this paper is to study and analyze the essential traffic characteristics of a 5.4-mile stretch of I-64-40 located within the St. Louis metropolitan area. The freeway experiences heavy congestion during peak periods attributed to factor...

Cable median barriers : a cost-effective means to save lives : research spotlight.

DOT National Transportation Integrated Search

2014-10-01

Median-crossover crashes are among the most hazardous events that : can occur on freeways, often leading to serious injury or death. In recent : years, high-tension cable median barriers have emerged as a cost-effective alternative to conventional ba...

Evaluation of adjacent AC and CRC pavement lanes : final report.

DOT National Transportation Integrated Search

1995-02-01

On some of Oregon's highways, particularly on the interstate freeways in Eastern Oregon, most of the heavy trucks travel in the outside lane (right lane). With this kind of truck traffic pattern, the right lane experiences significantly higher axle l...

Performance of alternative diamond interchange forms : Volume II--guidelines for selecting alternative diamond interchanges.

DOT National Transportation Integrated Search

2017-01-01

Service interchanges connect freeways to arterial roads and are the backbone of the U.S. road network. Improving the operations of service interchanges is possible by applying one of several new solutions: diverging diamond, single point interchanges...

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...

Effect of freeway level of service and driver education on truck driver stress : phase 1.

DOT National Transportation Integrated Search

2012-08-01

This research primarily deals with truck driver stress and its nature, stressors, and their mutual relationship. During the : study, the different demands of driving that are related to roads, vehicle, traffic conditions, driver predisposition to : s...

Potential of procedural knowledge to enhance advanced traveler information systems

DOT National Transportation Integrated Search

1997-01-01

The closure of a portion of the Santa Monica Freeway following the 1994 Northridge earthquake afforded the opportunity to study the behavior of motorists as they found their way around the collapsed bridges along alternate and detour routes. In this ...

Evaluating the impacts of proposed speed limit increases in Michigan : research spotlight.

DOT National Transportation Integrated Search

2014-07-01

Recent proposed speed limit legislation led MDOT to evaluate the : states current speed limit policies and potential alternatives. Currently, : Michigan freeways have a maximum speed limit of 70 mph for passenger : vehicles and 60 mph for trucks a...

15. LIGHTING DETAIL ON WAVERLY DRIVE OVERCROSSING HYPERION BOULEVARD. LAMPS ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

15. LIGHTING DETAIL ON WAVERLY DRIVE OVERCROSSING HYPERION BOULEVARD. LAMPS ALSO SEEN IN CA-272-13. LOOKING EAST/SOUTHEAST. - Glendale-Hyperion Viaduct, Spanning Golden State Freeway (I-5) & Los Angeles River at Glendale Boulevard, Los Angeles, Los Angeles County, CA

Innovative methods for calculation of freeway travel time using limited data : executive summary report.

DOT National Transportation Integrated Search

2008-08-01

ODOTs policy for Dynamic Message Sign : utilization requires travel time(s) to be displayed as : a default message. The current method of : calculating travel time involves a workstation : operator estimating the travel time based upon : observati...

Forterra Concrete Products, Inc. - Clean Water Act Public Notice

EPA Pesticide Factsheets

The EPA is providing notice of a proposed Administrative Penalty Assessment against Forterra Concrete Products, Inc., a business located at 511 E. John Carpenter Freeway, Irving, TX, 75062, for alleged violations at its facility located at 23600 W. 40th St

Systems engineering management plan : Dallas Integrated Corridor Management (ICM) demonstration project.

DOT National Transportation Integrated Search

2010-12-01

The purpose of the Dallas ICM System is to implement a multi-modal operations decision support tool enabled by real-time data pertaining to the operation of freeways, arterials, and public transit. The system will be shared between information system...

Assessment of vehicle performance in harsh environments using LSU driving simulator and numerical simulations.

DOT National Transportation Integrated Search

2015-12-01

With the economic booming development of coastal areas, the importance of the traffic planning becomes : obvious not only in a hurricane evacuation but also in the daily transportation. Vehicle performance on the : freeway during harsh environments i...

Guidance for effective use of pylons for lane separation on preferential lanes and freeway ramps.

DOT National Transportation Integrated Search

2013-05-01

Flexible pylons are gaining popularity as traffic channelizing devices in a variety of applications. The : flexible pylons are less rigid (as compared to concrete barriers) enabling easier access for emergency : vehicles and provide more positive con...

Evaluation of the effectiveness of ATM messages used during incidents : final report.

DOT National Transportation Integrated Search

2016-01-01

This project investigated the use of Intelligent Lane Control Signs based Active Traffic Management for : Incident Management on a heavily traveled urban freeway. The subject of the research was the ILCS : system on I-94 westbound in downtown Minneap...

Integrated corridor management initiative : demonstration phase evaluation, San Diego decision support system analysis test plan.

DOT National Transportation Integrated Search

2000-01-01

This report demonstrates the benefits and potential pitfalls of deploying and operating an integrated freeway and arterial management system. In particular, it discusses the lessons learned about the Medical Center Corridor (MCC) Project deployed in ...

Evaluation of ground mounted diagrammatic entrance ramp approach signs : executive summary.

DOT National Transportation Integrated Search

2000-10-01

The effectiveness of ground mounted diagrammatic signs in the context of urban : multi-lane arterials leading to a freeway was evaluated. This type of guide sign provides : much needed information well in advance of the interchange entrance, thus giv...

23 CFR 625.2 - Policy.

Code of Federal Regulations, 2010 CFR

2010-04-01

... § 625.2 Policy. (a) Plans and specifications for proposed National Highway System (NHS) projects shall..., restoration, and rehabilitation (RRR) projects, other than those on the Interstate system and other freeways..., bridges, the roadside, and appurtenances to a condition of structural or functional adequacy. (c) An...

Camera positioning and calibration techniques for integrating traffic surveillance video systems with machine-vision vehicle detection devices.

DOT National Transportation Integrated Search

2002-12-01

The Virginia Department of Transportation, like many other transportation agencies, has invested significantly in extensive closed circuit television (CCTV) systems to monitor freeways in urban areas. Although these systems have proven very effective...

Application of Bluetooth technology to rural freeway speed data collection ; executive summary report.

DOT National Transportation Integrated Search

2012-10-01

The Ohio Department of Transportation (ODOT) currently employs a network of side fire speed radar devices to measure travel speeds and travel times on their interstate network. While these devices measure the instantaneous spot speed, segment level s...

A comparison of freeway median crash frequency, severity, and barrier strike outcomes by median barrier type.

PubMed

Russo, Brendan J; Savolainen, Peter T

2018-08-01

Median-crossover crashes are among the most hazardous events that can occur on freeways, often resulting in severe or fatal injuries. The primary countermeasure to reduce the occurrence of such crashes is the installation of a median barrier. When installation of a median barrier is warranted, transportation agencies are faced with the decision among various alternatives including concrete barriers, beam guardrail, or high-tension cable barriers. Each barrier type differs in terms of its deflection characteristics upon impact, the required installation and maintenance costs, and the roadway characteristics (e.g., median width) where installation would be feasible. This study involved an investigation of barrier performance through an in-depth analysis of crash frequency and severity data from freeway segments where high-tension cable, thrie-beam, and concrete median barriers were installed. A comprehensive manual review of crash reports was conducted to identify crashes in which a vehicle left the roadway and encroached into the median. This review also involved an examination of crash outcomes when a barrier strike occurred, which included vehicle containment, penetration, or re-direction onto the travel lanes. The manual review of crash reports provided critical supplementary information through narratives and diagrams not normally available through standard fields on police crash report forms. Statistical models were estimated to identify factors that affect the frequency, severity, and outcomes of median-related crashes, with particular emphases on differences between segments with varying median barrier types. Several roadway-, traffic-, and environmental-related characteristics were found to affect these metrics, with results varying across the different barrier types. The results of this study provide transportation agencies with important guidance as to the in-service performance of various types of median barrier. Copyright © 2018 Elsevier Ltd. All rights reserved.

A dynamic feedback-control toll pricing methodology : a case study on Interstate 95 managed lanes.

DOT National Transportation Integrated Search

2013-06-01

Recently, congestion pricing emerged as a cost-effective and efficient strategy to mitigate the congestion problem on freeways. This study develops a feedback-control based dynamic toll approach to formulate and solve for optimal tolls. The study com...

Identification and evaluation of the cost-effectiveness of highway design features to reduce nonrecurrent congestion.

DOT National Transportation Integrated Search

2014-01-01

This research report presents the findings on the identification and evaluation of the use of highway geometric design features on freeways to reduce nonrecurrent congestion and improve travel time reliability. General guidance is provided on the ran...

Empirical observation of the impact of traffic oscillations on freeway safety : final report, OTREC-RR-10-13, September 2010.

DOT National Transportation Integrated Search

2010-09-01

Traffic oscillations are typical features of congested traffic flow that are characterized by recurring decelerations : followed by accelerations (stop-and-go driving). The negative environmental impacts of these oscillations are widely : accepted, b...

Bringing smart transport to Texans : ensuring the benefits of a connected and autonomous transport system in Texas--final report.

DOT National Transportation Integrated Search

2016-11-01

Link to appendices is included. : This project develops and demonstrates a variety of smart-transport technologies, policies, and practices for : highways and freeways using connected autonomous vehicles (CAVs), smartphones, roadside equipment, and r...

The Tire Noise Performance of Nevada Highway Pavements: On-Board Sound Intensity (OBSI) Measurement

DOT National Transportation Integrated Search

2008-06-01

On Board Sound Intensity measurements were conducted on freeway segments in the vicinity of Las Vegas and Reno, Nevada in an effort to document the tire-pavement noise levels of existing pavements. Tested pavements included Portland Cement Concrete (...

Effects of Raising Speed Limits on Motor Vehicle Emissions

DOT National Transportation Integrated Search

1997-03-01

In 1974 the Federal government introduced a national speed limit of 55 miles per hour (mph) in response to the Arab oil embargo and subsequent energy crisis. This limit was raised to 65 mph for rural interstate freeways in 1987. In November of 1995, ...

Copy Photograph (original negative in possession of LSA Associates, Irvine, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Copy Photograph (original negative in possession of LSA Associates, Irvine, California) Rebecca Conard, Photographer, January 1989 STORAGE SHED, WEST (FRONT), LOOKING EAST - Irvine Ranch Agricultural Headquarters, Boyd Tenant House, Southeast of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

Photocopy of photograph (original negative in possession of LSA Associates, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Photocopy of photograph (original negative in possession of LSA Associates, Irvine, California) Rebecca Conard, Photographer, January 1989 NORTH SIDE, FROM (REAR) LOOKING SOUTHEAST - Irvine Ranch Agricultural Headquarters, Boyd Tenant House, Southeast of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

Photocopy of photograph (original negative in possession of LSA Associates, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Photocopy of photograph (original negative in possession of LSA Associates, Irvine, California) Rebecca Conard, Photographer, January 1989 SOUTH SIDE AND YARD, FACING NORTHEAST - Irvine Ranch Agricultural Headquarters, Boyd Tenant House, Southeast of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

Photocopy of photograph (original negative in possession of LSA Associates, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Photocopy of photograph (original negative in possession of LSA Associates, Irvine, California) Rebecca Conard, Photographer, January 1989 WINDOW DETAIL, NORTH SIDE, LOOKING SOUTH - Irvine Ranch Agricultural Headquarters, Boyd Tenant House, Southeast of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

Field evaluation of unlighted overhead guide signs using older drivers : executive summary report.

DOT National Transportation Integrated Search

2003-08-01

Problem: In the preceding Unlighted Overhead Guide : Sign Feasibility Study, it was determined that : the lighting of overhead guide signs on : freeways could be eliminated if white : microprismatic Type VII or Type IX legends : were used on green be...

I-40 trucking operations and safety analyses and strategic planning initiatives.

DOT National Transportation Integrated Search

2010-04-01

Interstate 40 composes a major link of this system. This highway is a major eastwest : freeway that spans a length of 2,559 miles. Interstate 40 originates near I- : 15 in Barstow, California and then passes through Arizona, New Mexico, Texas, : Okla...

Evaluating the impacts of speed limit policy alternatives.

DOT National Transportation Integrated Search

2014-07-01

As of June 2014, Michigan is one of eight states with a differential speed limit in place on its rural : freeways, which sets a maximum speed of 70 mph for passenger vehicles and 60 mph for trucks and : buses. In select urban environments, these spee...

New Jersey I-80 and I-287 HOV lane case study

DOT National Transportation Integrated Search

2000-07-01

This report documents the New Jersey I-80 and I-287 high-occupancy vehicle (HOV) lane case study. Information is presented on planning, implementing, operating, and redesignating the HOV lanes on the two freeways. The operation of the lanes is compar...

An evaluation of the benefits of the Alabama service and assistance patrol : final report.

DOT National Transportation Integrated Search

2009-12-01

The Alabama Service and Assistance Patrol (A.S.A.P.) is a freeway service patrol operated by : the Alabama Department of Transportation (ALDOT) in the Birmingham region of Alabama. : This patrol of service vehicles travels continuously on approximate...

Managed lane travelers : do they pay for travel as they claimed they would?

DOT National Transportation Integrated Search

2011-05-01

This study examined if travelers are paying for travel on managed lanes (MLs) as they indicated that they : would in a 2008 survey. To achieve the objectives, an Internet-based stated preference (SP) survey of : Houstons Katy Freeway travelers was...

Optimal placement of point detectors on Virginia's freeways : case studies of Northern Virginia and Richmond.

DOT National Transportation Integrated Search

2008-01-01

In Virginia, point detectors in the Northern Virginia and Hampton Roads regions are placed at approximately 1/2 mile spacing. This density is a product of early requirements for incident detection that have proven ineffective and perhaps unnecessary....

Validation and augmentation of Inrix arterial travel time data using independent sources : [research summary].

DOT National Transportation Integrated Search

2015-02-01

Although the freeway travel time data has been validated extensively in recent : years, the quality of arterial travel time data is not well known. This project : presents a comprehensive validation scheme for arterial travel time data based : on GPS...

Performance measures to characterize directional corridor travel time delay based on probe vehicle data : final report.

DOT National Transportation Integrated Search

2015-10-01

Anonymous probe vehicle data are currently being collected on roadways throughout the United States. These data are being incorporated into local and statewide mobility reports to measure the performance of freeways and arterial systems. Predefined s...

Real time estimation of arterial travel time and operational measures through integration of real time fixed sensor data and simulation.

DOT National Transportation Integrated Search

2012-02-01

A wide variety of advanced technological tools have been implemented throughout Georgias : transportation network to increase its efficiency. These systems are credited with reducing or : maintaining freeway congestion levels in light of increasin...

Evaluation of ground mounted diagrammatic entrance ramp approach signs : research implementation plan.

DOT National Transportation Integrated Search

2006-04-26

STATEMENT OF NEED: The effectiveness of ground mounted diagrammatic signs in the context of urban multi-lane arterials leading to a : freeway are to be evaluated. This type of guide sign provides much needed information well in advance of the : inter...

Comparing countermeasures for mitigating wrong-way entries onto limited access facilities.

DOT National Transportation Integrated Search

2017-03-01

Wrong-way crashes are a major cause for safety concerns along freeways and limited-access facilities. Although wrong-way crashes account for a relatively small portion of total crashes, the impact between two cars crashing into each other at high spe...

Socio-economic effect of seismic retrofit implemented on bridges in the Los Angeles highway network.

DOT National Transportation Integrated Search

2008-12-01

This research studied socio-economic effect of the seismic retrofit implemented on bridges in Los Angeles Area : Freeway Network. Firstly, advanced FE (Finite Element) modeling and nonlinear time history analysis are carried out to : evaluate the sei...

ARC-1932-A88-0284-2

NASA Image and Video Library

1932-05-10

USS AKRON at Moffett Field, Mr. & Mrs. Charles T. Johnson of San Jose and their daughter Ruth. It was possible for the public to park on the shoulder of Bayshore Freeway and walk out on the field to inspect the 'AKRON'. No fences or security guards!

Centerline rumble strips on rural highways shown to cut crashes by half : research spotlight.

DOT National Transportation Integrated Search

2015-03-01

In 2008, Michigan launched a major systemwide installation of both : centerline and shoulder rumble strips on 5,400 miles of its rural, : non-freeway highway system. This unprecedented initiative was : accomplished during a three-year period ending i...

A case study : the Las Vegas Freeway and Arterial Management System : use of a systems manager contractor to procure ITS

DOT National Transportation Integrated Search

2000-03-01

Procurement of Intelligent Transportation System (ITS) projects using Federal-aid funds can present challenges that are not typically observed in traditional transportation projects. Many roadway improvement projects involve the two-step "Design-Bid-...

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...

Big I (I-40/I-25) reconstruction & ITS infrastructure.

DOT National Transportation Integrated Search

2010-04-20

The New Mexico Department of Transportation (NMDOT) rebuilt the Big I interchange in Albuquerque to make it safer and more efficient and to provide better access. The Big I is where the Coronado Interstate (I-40) and the Pan American Freeway (I-25) i...

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...

Development of active traffic management strategies for Minnesota freeway corridors : final report.

DOT National Transportation Integrated Search

2015-06-01

In this study, the effectiveness of the I-35W variable advisory speed limit system on the improvement of the traffic : flow was evaluated with the real traffic data. The analysis results indicate there was significant reduction in the : average maxim...

Guidelines for the use of pavement marking symbols at freeway interchanges : final report.

DOT National Transportation Integrated Search

2010-03-01

Pavement marking technology has advanced to allow for the use of large multi-color symbols to be placed on : the pavement as a means of providing drivers with another source of information from which they can make : good driving decisions. This proje...

Guidelines On The Selection And Design Of Messages For Changeable Message Signs

DOT National Transportation Integrated Search

1992-06-01

THIS REPORT PRESENTS GUIDELINES ON THE DESIGN OF CHANGEABLE MESSAGE SIGN (CMS) MESSAGES FOR USE IN FREEWAY CORRIDORS FOR INCIDENT MANAGEMENT AND ROUTE DIVERSION. IT IS A COMPANION TO REPORT NO. FHWA/TX-92/1232-9, WHICH IS A PRIMER ON THE CHARACTERIST...

Concept of operations and policy implications for unmanned aircraft systems use for traffic incident management (UAS-TIM) : final report.

DOT National Transportation Integrated Search

2017-03-01

Texas freeways experience considerable traffic congestionsome from high traffic volumes and some from traffic incidents, both minor (e.g., crashes, stalls, and road debris) and major (e.g., vehicle rollovers, chemical spills, flooding, and hurrica...

Project #8, Task 1 - Travel Information Services (TIS), Inventory Of Traveler Information Services And Commercial Opportunities In The I-95 Corridor

DOT National Transportation Integrated Search

1995-12-01

CONTINUED FROM DOCUMENT NUMBER 6303 : RESEARCH AND DEVELOPMENT OR R&D, ELECTRONIC PAYMENT SYSTEMS, AUTOMATED FARE COLLECTION, EMERGENCY MANAGEMENT SERVICES OR EMS, FREEWAY MANAGEMENT SYSTEMS, INCIDENT MANAGEMENT/INCIDENT DETECTION : THE L-95 CORRI...

Costs and benefits of strategic acquisition of limited access right-of-way at freeway interchange areas

DOT National Transportation Integrated Search

2004-11-01

The purpose of this research is to assess the cost effectiveness of purchasing additional limited access right-of-way at the time of construction in lieu of retrofitting interchange areas after functional failure. The findings indicate that the long ...

Photocopy of photograph (original negative in possession of LSA Associates, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Photocopy of photograph (original negative in possession of LSA Associates, Irvine, California) Beth Padon, photographer, 1985 WEST (REAR) IN RELATION TO GARAGE, LOOKING NORTH - Irvine Ranch Agricultural Headquarters, Boyd Tenant House, Southeast of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

Photocopy of photograph (original negative in possession of LSA Associates, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Photocopy of photograph (original negative in possession of LSA Associates, Irvine, California) Rebecca Conard, Photographer, January 1989 EAST (FRONT) AND NORTH SIDE, LOOKING SOUTHWEST - Irvine Ranch Agricultural Headquarters, Boyd Tenant House, Southeast of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

State of the practice for shoulder and center line rumble strip implementation on non-freeway facilities.

DOT National Transportation Integrated Search

2017-03-01

Center line rumble strips (CLRSs) and shoulder rumble strips (SRSs) are proven countermeasures for reducing roadway departure crashes, including head-on and run-off-road crashes. The objectives of this project were twofold. The first objective was to...

An assessment of high-occupancy vehicle facilities (HOV) in North America : executive report

DOT National Transportation Integrated Search

This executive report provides an overall summary of the major elements of the assessment of high-occupancy vehicle (HOV) lane projects located either on freeways or in separate rights-of-way in North America. The report includes a discussion of the ...

Heavy Metal.

ERIC Educational Resources Information Center

Black, Susan

2001-01-01

The Centers for Disease Control and Prevention (CDC) estimate that more than 1 million children ages 5 and under are afflicted with unsafe amounts of lead. Schools can be a source of lead poisoning. Other sources include playgrounds near freeways, playground equipment, contaminated soil, and technology rooms with lead-bearing supplies. Sidebars…

Houston managed lanes case study : the evolution of the Houston HOV system

DOT National Transportation Integrated Search

2003-09-01

A nine-mile contraflow High Occupancy Vehicle (HOV) lane on the I-45 North Freeway in Houston, Texas was implemented as a demonstration project in 1979. This demonstration borrowed an off-peak direction traffic lane for use by buses and vanpools in t...

78 FR 68135 - Environmental Impact Statement: Los Angeles County, California

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-13

... part of 2014. FOR FURTHER INFORMATION CONTACT: Tami Podesta, California Department of Transportation... no access control. SR-138 Northwest Corridor Improvement Project proposes to improve the highway as a freeway, expressway with access control and/or traffic system/multi- modal facility. The SR-138 currently...

Development of a Traffic Management Decision Support Tool for Freeway Incident Traffic Management (FITM) Plan Deployment

DOT National Transportation Integrated Search

2017-12-01

Traffic incidents have long been recognized as the main contributor to congestion in highway networks. Thus, contending with non-recurrent congestion has been a priority task for most highway agencies over the past decades. Under most incident scenar...

Intelligent Transportation Systems, The National Architecture, A Framework For Integrated Transportation Into The 21St Century

DOT National Transportation Integrated Search

1985-08-01

The primary objective of this study was to determine if freeway lighting can be reduced or eliminated during nighttime periods when traffic volume is much lower than design capacity without causing significant reductions in the ability of drivers to ...

The Columbus metropolitan freeway management system (CMFMS) effectiveness study : part 2, the after study, research implementation plan.

DOT National Transportation Integrated Search

2006-08-01

STATEMENT OF NEED: The increasing number of ITS systems deployed around the nation is creating a need to determine the benefits of : these systems; thus, justifying their cost expenditures. The Ohio Department of Transportation, in conjunction with :...

Field evaluation of unlighted overhead guide signs using older drivers : research implementation plan.

DOT National Transportation Integrated Search

2006-04-01

STATEMENT OF NEED: In the preceding Unlighted Overhead Guide Sign Feasibility Study, it was determined that the lighting of overhead : guide signs on freeways could be eliminated if white micro-prismatic Type VII or Type IX legends were used on : gre...

Development of a Traffic Management Decision Support Tool for Freeway Incident Traffic Management (FITM) Plan Deployment : Research Summary

DOT National Transportation Integrated Search

2017-12-01

In designing an effective traffic management plan for non-recurrent congestion, it is critical for responsible highway agencies to have some vital information, such as estimated incident duration, resulting traffic queues, and the expected delays. Ov...

Highway median impacts on wildlife movement and mortality : state of the practice survey and gap analysis.

DOT National Transportation Integrated Search

2006-10-01

Highway median barriers are used to separate lanes of traffic and enhance motorist safety on freeways and multi-lane interstate highways. : Median barriers of all types have the potential to impede animal movements across highways. Barriers may also ...

I-95/I-395 HOV restriction study : volume 1 : summary report

DOT National Transportation Integrated Search

1999-02-01

The I-95/I-395 High Occupancy Vehicle (HOV) facility is a reversible two-lane freeway, about 27 miles long, between the southern terminus at Dumfries near Route 234 and the northern terminus between Route 27 and Eads Street in Arlington. Beyond this ...

Contextual oblique view of north side and east rear, view ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Contextual oblique view of north side and east rear, view to southwest from Franklin Street showing partially cleared freeway right-of-way, and line of mature deodar cedar trees along North Fulton Avenue - Ira H. Brooks House, 350 North Fulton Avenue, Fresno, Fresno County, CA

Real-time information dissemination requirements for Illinois per new federal rule.

DOT National Transportation Integrated Search

2015-02-01

Travelers on U.S. freeways could now be better-informed than ever before, because of a new federal legislation. : The Final Rule 23 CFR 511 has mandated that after November 8, 2014, states provide real-time traveler data : along all limited-access ro...

Evaluation of freeway motorist assist program : final report, September 30, 2009.

DOT National Transportation Integrated Search

2010-02-01

This evaluation of the Motorist Assist (MA) program in St. Louis estimated that MA has an annual benefit-cost ratio (B/C) of 38.25:1 using 2009 dollars. This estimate was based on nationally accepted AASHTO methodology and was based on 1082 secondary...

Effects of changing HOV lane occupancy requirements : El Monte busway case study

DOT National Transportation Integrated Search

2002-06-01

In 1999, the California Legislature passed Senate Bill 63, which lowered the vehicle-occupancy requirement on the El Monte Busway on the San Bernardino (I-10) Freeway from three persons per vehicle (3+) to two persons per vehicle (2+) full time. The ...

Development of prototype decision support systems for real-time freeway traffic routing. Volume I.

DOT National Transportation Integrated Search

1998-01-01

For a traffic management system (TMS) to improve traffic flow, TMS operators must develop effective routing strategies based on the data collected by the system. The purpose of this research was to build prototype decision support systems (DSS) for t...

Safety and operational performance evaluation of four types of exit ramps on Florida's freeways (final report).

DOT National Transportation Integrated Search

2010-12-01

This project mainly focuses on exit ramp performance analysis of safety and operations. In addition, issues of advance guide sign for exit ramp are also mentioned. : Safety analysis evaluates safety performances of different exit ramps used in Florid...

Seat-belt wearing and driving behavior: an instrumented-vehicle study.

PubMed

Janssen, W

1994-04-01

Less-than-expected fatality reductions after seat-belt legislation has been introduced in a jurisdiction may be explained in terms of selective recruitment of parts of the driving population and/or behavioral adaptation by beginning belt users. The present investigation has compared the relative merits of these two hypotheses at the level of individual driver behavior. In the initial study the driving behavior of groups of habitual wearers and nonwearers of the belt was compared. Nonwearers made two trips, one with the belt on and one without the belt. Habitual wearers drove belted only. The main part of the experiment was a 105 km freeway route. Two additional tasks of a somewhat more critical nature, a double lane-change manoeuvre and the performance of a braking manoeuvre in front of a fixed obstacle, were performed after the freeway trips. Factor analysis on 39 variables describing driving behavior on the road and during the additional tasks resulted in five factors. One of these, the factor describing the distribution of driving speed on the freeway, differentiated between nonwearers and wearers (thus yielding support for the selective recruitment hypothesis) as well as between wearing and not wearing the belt by the same drivers (thus yielding support for the behavioral adaptation hypothesis). In the follow-up study the original wearers and nonwearers were assigned to one of four experimental treatments: (i) the promise by the experimenter of a considerable incentive for not having a culpable motor vehicle accident over a period of a year. Half the habitual wearer subjects were assigned to this condition. The expectation was that this group would become more careful in their driving; (ii) a control group, consisting of the remaining habitual wearers; (iii) the agreement between the experimenter and the subject that the latter would buckle up in everyday driving for the year to come--half the habitual nonwearer subjects were assigned to this condition; (iv) a control group to the previous treatment, consisting of the remaining habitual nonwearers. All subjects returned for repeat measurements, consisting of the freeway trips plus additional tasks, three times over the next year. The main result was that beginning wearers (group iii) showed signs of continuing behavioral adaptation, in the form of increased speed and increased propensity for close following, as well as several minor effects. The "incentive" group (group i), however, did not change driving behavior in the expected sense, i.e. in the safe direction.

Improving work zone safety through speed management.

DOT National Transportation Integrated Search

2013-06-01

Safety hazards are increased in highway work zones as the dynamics of a work zone introduce a constantly changing : environment with varying levels of risk. Excessive speeding through work and maintenance zones is a common occurrence : which elevates...

Resources on work zone safety and mobility performance monitoring and measurement.

DOT National Transportation Integrated Search

2013-01-01

Work zone performance measures are metrics that help quantify how work zones impact travelers, residents, businesses, and workers. Some performance measures describe how an individual work zone impacts these audiences; other performance measures desc...

Improving the effectiveness of smart work zone technologies.

DOT National Transportation Integrated Search

2016-11-01

This project evaluates the effectiveness of sensor network systems for work zone traffic estimation. The comparative analysis is : performed on a work zone modeled in microsimulation and calibrated with field data from two Illinois work zones. Realis...

Chapter A. The Loma Prieta, California, Earthquake of October 17, 1989 - Strong Ground Motion

USGS Publications Warehouse

Borcherdt, Roger D.

1994-01-01

Strong ground motion generated by the Loma Prieta, Calif., earthquake (MS~7.1) of October 17, 1989, resulted in at least 63 deaths, more than 3,757 injuries, and damage estimated to exceed $5.9 billion. Strong ground motion severely damaged critical lifelines (freeway overpasses, bridges, and pipelines), caused severe damage to poorly constructed buildings, and induced a significant number of ground failures associated with liquefaction and landsliding. It also caused a significant proportion of the damage and loss of life at distances as far as 100 km from the epicenter. Consequently, understanding the characteristics of the strong ground motion associated with the earthquake is fundamental to understanding the earthquake's devastating impact on society. The papers assembled in this chapter address this problem. Damage to vulnerable structures from the earthquake varied substantially with the distance from the causative fault and the type of underlying geologic deposits. Most of the damage and loss of life occurred in areas underlain by 'soft soil'. Quantifying these effects is important for understanding the tragic concentrations of damage in such areas as Santa Cruz and the Marina and Embarcadero Districts of San Francisco, and the failures of the San Francisco-Oakland Bay Bridge and the Interstate Highway 880 overpass. Most importantly, understanding these effects is a necessary prerequisite for improving mitigation measures for larger earthquakes likely to occur much closer to densely urbanized areas in the San Francisco Bay region. The earthquake generated an especially important data set for understanding variations in the severity of strong ground motion. Instrumental strong-motion recordings were obtained at 131 sites located from about 6 to 175 km from the rupture zone. This set of recordings, the largest yet collected for an event of this size, was obtained from sites on various geologic deposits, including a unique set on 'soft soil' deposits (artificial fill and bay mud). These exceptional ground-motion data are used by the authors of the papers in this chapter to infer radiation characteristics of the earthquake source, identify dominant propagation characteristics of the Earth?s crust, quantify amplification characteristics of near-surface geologic deposits, develop general amplification factors for site-dependent building-code provisions, and revise earthquake-hazard assessments for the San Francisco Bay region. Interpretations of additional data recorded in well-instrumented buildings, dams, and freeway overpasses are provided in other chapters of this report.

Evaluation of work zone speed limits : an objective and subjective analysis of work zones in Missouri.

DOT National Transportation Integrated Search

2011-02-01

This study objectively and subjectively examined speed characteristics and driver compliance with the posted speed limit : in Missouri work zones. The objective evaluation collected vehicle speeds from four work zones with different : configurations ...

Idea Project Final Report, A Sequential Hypothesis Testing-Based Decision-Making System For Freeway Incident Response

DOT National Transportation Integrated Search

1995-10-01

THIS INVESTIGATION WAS COMPLETED AS PART OF THE ITS-IDEA PROGRAM WHICH IS ONE OF THREE IDEA PROGRAMS MANAGED BY THE TRANSPORTATION RESEARCH BOARD (TRB) TO FOSTER INNOVATIONS IN SURFACE TRANSPORTATION. IT FOCUSES ON PRODUCTS AND RESULT FOR THE DEVELOP...

Phase II : operational and safety-based analyses of varied toll lane configurations.

DOT National Transportation Integrated Search

2016-08-01

The Puerto Rico Dynamic Toll Lane (DTL) is a 6.44 mi (10.4 km) reversible facility within a stretch of freeway PR-22 that operates a congestion pricing system; the first of its kind in the Commonwealth of Puerto Rico. This managed lane system is shar...

Differential Effects of Particulate Matter Upwind and Downwind of an Urban Freeway in an Allergic Mouse Model

EPA Science Inventory

Near-road exposure to air pollutants has been associated with decreased lung function and other adverse health effects in susceptible populations. This study was designed to investigate whether different types of near-road particulate matter (PM) contribute to exacerbation of all...

The environmental psychology of shopping: assessing the value of trees

Treesearch

Kathleen L. Wolf

2007-01-01

A multi-study research program has investigated how consumers respond to trees in various business settings in cities and towns. Some studies focused on central business districts, others tested perceptions along freeways and arterials. Results are remarkably consistent. Trees not only positively affect judgments of visual quality but,...

View of substructure of Sixth Street Bridge overcrossing of Los ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View of substructure of Sixth Street Bridge overcrossing of Los Angeles River. Looking west. Note dark hole at lower with is access ramp to river channel seen in HAER CA-176-56 - Sixth Street Bridge, Spanning 101 Freeway at Sixth Street, Los Angeles, Los Angeles County, CA

New York State Department of Transportation, Lower Hudson Valley, Region 8 : intelligent transportation systems early deployment planning study

DOT National Transportation Integrated Search

1998-11-01

The purpose of this study is to provide the framework for future implementation of Intelligent Transportation Systems (ITS) in the Lower Hudson Valley area. The focus of the planning study is the regional freeway system, major arterial routes and the...

U.S. Border Crossings with Canada and Mexico - Port Facilities, Inventory and Constraints. Volume 1.

DOT National Transportation Integrated Search

2000-09-01

This report summarizes the New Jersey I-80 and I-287 high-occupancy vehicle (HOV) lane case study. Information on planning, implementing, operating, and redesignating the HOV lanes on the two freeways is presented. The factors that appear to have inf...

Development of criteria and guidelines for installing, operating, and removing TxDOT ramp control signals.

DOT National Transportation Integrated Search

2009-05-01

The Texas Department of Transportation (TxDOT) uses ramp control signals (also called ramp meters or : flow signals) to control the rate at which vehicles enter the freeway. This helps TxDOT (1) promote a more : consistent and uniform flow of traffic...

Integration of off-ramp and arterial signal controls to minimize the recurrent congestion on the I-495 Capital Beltway.

DOT National Transportation Integrated Search

2010-11-01

This study developed an integrated control model to contend with the impact of off-ramp queue spillback on both the freeway and arterials within the interchange control boundaries. The entire control system consists of two levels that compute the opt...

RHODES-ITMS Tempe field test project : implementation and field testing of RHODES, a real-time traffic adaptive control system

DOT National Transportation Integrated Search

2001-09-01

RHODES is a traffic-adaptive signal control system that optimally controls the traffic that is observed in real time. The RHODES-ITMS Program is the application of the RHODES strategy for the two intersections of a freeway-arterial diamond interchang...

Recommendations for placement of cable median barriers on 6:1 and 4:1 sloped medians with horizontal curvatures.

DOT National Transportation Integrated Search

2012-09-01

This report summarizes the research efforts of using finite element modeling and simulations to evaluate the performance of generic lowtension : cable median barriers (CMBs) on four-lane and six-lane freeways with a 46-foot median, horizontal curvatu...

Development of a queue warning system utilizing ATM infrastructure system development and field-testing : final report.

DOT National Transportation Integrated Search

2017-06-13

MnDOT has already deployed an extensive infrastructure for Active Traffic Management (ATM) on I-35W and I-94 with plans to expand on other segments of the Twin Cities freeway network. The ATM system includes intelligent lane control signals (ILCS) sp...

Simulation-based decision-making tool for adaptive traffic signal control on Tarrytown Road in the City of White Plains.

DOT National Transportation Integrated Search

2013-01-01

Transportation corridors are vital for our region and even the nations economy and quality of life. A corridor is usually a complicated system that may span multi-jurisdictions, contains multiple modes, include both freeways and local arterials, a...

San Antonio's medical center corridor : lessons learned from the Metropolitan Model Deployment Initiative : reducing delay through integrated freeway and arterial management

DOT National Transportation Integrated Search

1997-04-01

This report presents the results of research on procurement-related legal and non-technical issues which may be constraining the deployment of Intelligent Transportation Systems (ITS). The reports focus is on State and local procurement practices ...

A comparison of freeway and parallel major arterial corridors : a study of safety patterns in the Denver metropolitan area.

DOT National Transportation Integrated Search

2015-11-01

Observations and initial examination of ADT and peak-hour volume data on Denver regional arterials suggests questions as : to if and why they are happening, and what the implications are on corridor travel and accident patterns? This proposed : resea...

Network origin-destination demand estimation using limited link traffic counts : strategic deployment of vehicle detectors through an integrated corridor management framework.

DOT National Transportation Integrated Search

2009-10-15

In typical road traffic corridors, freeway systems are generally well-equipped with traffic surveillance systems such as vehicle detector (VD) and/or closed circuit television (CCTV) systems in order to gather timely traffic information for traffic c...

Buyers Guide: Communications Software--Overview; Ratings Digest; Reviews; Benchmarks.

ERIC Educational Resources Information Center

Lockwood, Russ; And Others

1988-01-01

Contains articles which review communications software. Includes "Crosstalk Mark 4,""ProComm,""Freeway Advanced,""Windows InTalk,""Relay Silver," and "Smartcom III." Compares in terms of text proprietary, MCI upload, Test ASCII, Spreadsheet Proprietary, Text XMODEM, Spreadsheet XMODEM, MCI Download, Documentation, Support and Service, ease of use,…

Evaluating the appropriate level of service for Michigan rest areas and welcome centers considering safety and economic factors : executive summary.

DOT National Transportation Integrated Search

2012-04-30

The Michigan Department of Transportation (MDOT) currently operates and maintains : 81 rest areas, including 14 welcome centers, along freeways and other major roadways. Public : rest areas in Michigan serve a broad range of travelers, including vaca...

Executive report : effects of changing HOV lane occupancy requirements : El Monte busway case study.

DOT National Transportation Integrated Search

2002-09-01

In 1999, the California Legislature passed Senate Bill 63, which lowered the vehicle-occupancy requirement on the El Monte Busway on the San Bernardino (I-10) Freeway from three persons per vehicle (3+) to two persons per vehicle (2+) full time. The ...

Comparison of dual-phase and static changeable message signs to convey airline information on interstate freeways.

DOT National Transportation Integrated Search

2010-01-01

The authors used a fully interactive PC-based STISIM driving simulator to compare dual-phase Changeable Message Signs (CMSs) and static CMSs. The participants were 120 licensed drivers from three age groups: 18-24, 32-47, and 55-65 years of age. They...

Structural equation models of VMT growth in US urbanised areas.

USGS Publications Warehouse

Ewing, Reid; Hamidi, Shima; Gallivan, Frank; Nelson, Arthur C.; Grace, James B.

2014-01-01

Vehicle miles travelled (VMT) is a primary performance indicator for land use and transportation, bringing with it both positive and negative externalities. This study updates and refines previous work on VMT in urbanised areas, using recent data, additional metrics and structural equation modelling (SEM). In a cross-sectional model for 2010, population, income and freeway capacity are positively related to VMT, while gasoline prices, development density and transit service levels are negatively related. Findings of the cross-sectional model are generally confirmed in a more tightly controlled longitudinal study of changes in VMT between 2000 and 2010, the first model of its kind. The cross-sectional and longitudinal models together, plus the transportation literature generally, give us a basis for generalising across studies to arrive at elasticity values of VMT with respect to different urban variables.

Evaluation Of Traffic Control Devices For Rural High-Speed Maintenance Work Zones

DOT National Transportation Integrated Search

2000-10-01

This report documents the first year activities of a two-year project in which various work zone traffic control devices, treatments, and practices were implemented and evaluated. The focus was on rural high-speed work zones. Nine work zones were stu...

Work zone intrusion alert technologies : assessment and practical guidance : final report.

DOT National Transportation Integrated Search

2017-06-01

A work zone intrusion alert technology is a type of safety system that is used in a roadway work zone to alert field workers and secure time for them to escape when errant vehicles intrude into the work zone. Although such technologies have potential...

23 CFR 630.1006 - Work zone safety and mobility policy.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 23 Highways 1 2011-04-01 2011-04-01 false Work zone safety and mobility policy. 630.1006 Section 630.1006 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS PRECONSTRUCTION PROCEDURES Work Zone Safety and Mobility § 630.1006 Work zone safety and mobility...