The goal of this study was to provide a better understanding of the impacts of route guidance on urban arterials and networks controlled by traffic signals. Control and timing strategies to handle diverted traffic from the freeways to surface streets were developed and tested through simulation on real-life networks. These strategies showed that for a small number of diverted vehicles, optimal timing plans for favoring the diverted routes improved the performance of diverted traffic without significant adverse impacts to the rest of the network.

This report describes the enhancements to the video data collection of the Berkeley Highway Laboratory (BHL), a unique surveillance system on a section of I-80 freeway in the city of Emeryville. We also present the development of advanced machine vision algorithms to process the video data to generate vehicle trajectories. A pilot application of the BHL system produced trajectories of over 4700 vehicles. This is the largest dataset of vehicle trajectories on extended freeway segments. In addition, algorithms and software were developed for data analysis and visualization.

This report presents the findings from the evaluation of a statewide initiative to retime traffic signals to produce more energy-efficient traffic flow: California's FuelEfficient Traffic Signal Management (FETSIM) Program. During the 11 years of the Program, over 160 cities and counties have retimed a total of 12,245 signals under grants from the FETSIM Program, in 334 projects. Improved timings have reduced vehicular delays by 14 percent in project areas; stops have been decre~sed by 13 percent. Overall travel times through these systems have dropped by 7 percent and fuel consumption has been cut by 8 percent. The reduction in fuel expenditures alone has produced annual savings of $85.1 million for California motorists--more than 5 times the total cost of the FETSIM Program. Reduced vehicular wear and tear and faster travel times added as much as $189.3 million annually in user benefits. Other benefits include reduction of air pollution emissions, traffic safety improvements, and better operating conditions for public transit vehicles. The Program also strengthened the capabilities of local traffic engineering staff, and has built better data bases for future traffic studies in participating communities.

The FETSIM Program was carefully designed to off er local agencies the tools, know-how and financial assistance necessary for improving the timing of traffic signal systems. Grants have been awarded for all aspects of retiming, including the costs of data collection, development of timing plans, implementation and field evaluation. Training and technical assistance in advanced methods for achieving optimal signal timing has been provided to the staff and consultants of the participating agencies. A number of research and development activities in support of the Program have produced improved analysis tools for traffic signal management that are used by practicing engineers nationwide.

The FETSIM Program has served as a model for several statewide signal management programs across the country. It has received recognition as a major success, not only in California but nationally. In 1985, the California Energy Commission and the California Department of Transportation received the Institute of Transportation Engineers' Transportation Energy Conservation Award for the Program.

The report describes the findings of a study to develop a simulation testbed for the Santa Monica freeway corridor. The study created one of the largest freeway corridor networks coded for the CORSIM microscopic simulation model. The coded network consists of about 10 miles of I-10 freeway and a surface street network with 75 signalized intersections. The results from the simulation experiments indicate that several CORSIM model parameters need to be adjusted in order to accurately simulate freeway facilities for California conditions. The calibrated CORSIM model produced reasonable and consistent results for freeway lane drops, merging areas and weaving sections. Similar results were obtained from the limited experiments with the INTEGRATION simulation model. Recommendations are provided for developing a comprehensive simulation testbed for the study area including data collection requirements, model application, model calibration and validation and analysis of alternative ATMIS strategies.

This report discusses the major factors which influence the benefits from transit priority. It reviews existing control strategies that have been implemented in signal controlled networks. A number of control strategies to improve transit performance are proposed along with an analysis technique to evaluate their effectiveness. The strategies were tested on a major arterial. Recommendations are given, based on the results.

The Freeway Service Patrol (FSP) is an incident management program implemented by Caltrans, the California Highway Patrol and local partner agencies to quickly detect and assist disabled vehicles and reduce non-recurring congestion along the freeway during peak commute hours.  The first FSP program was piloted in Los Angeles and was later expanded to other regions by state legislation in 1991.  As of June 2020, there were sixteen participating FSP Programs operating in California, deploying 305 tow trucks and covering over 1,900 (centerline) miles of congested California freeways.

The purpose of this research project was to evaluate the effectiveness of the Caltrans FSP program in reducing incident durations and removal of other obstructions that directly contribute to freeway congestion for Caltrans fiscal year 2020-2021.  The project provides valuable information to agencies managing the FSP program so that resources are distributed within the various statewide FSP operations in the most efficient and cost-effective manner possible.  The tools used and the operational performance measures provided by this research effort will significantly contribute on the ongoing agencies’ efforts to improve the efficiency and effectiveness of the FSP program.

A number of adaptive control algorithms have been developed in the US and overseas. However, the practical implementation of adaptive control is limited especially in California. There is a need to develop adaptive control algorithms, evaluate their performance through a field test, and develop a deployment plan for possible Statewide application. The objectives of the study are identify and select the most promising of existing adaptive control algorithms, develop improved algorithm(s) as appropriate, conduct field tests on real-world arterials, and develop recommendations for deployment of adaptive control.

This report describes the work performed in the first phase of the research conducted under PATH Task Order 5322. It summarizes the findings from the literature review and presents the study methodology. A section of the Pacific Coast Highway in the city of Lomita was selected as the test site for evaluation of adaptive signal control strategies. A methodology was developed to develop a time-varying origin-destination (OD) matrix from the system loop detector data at the site. The calibrated OD matrix was applied to a microscopic representation of the site created in PARAMICS. Finally, a plug-in for simulating signal control in PARAMICS was written. It simulates non-adaptive strategies such as pretimed, isolated actuated, coordinated actuated, traffic responsive, and critical intersection control, as well as adaptive strategies such as RHODES and TUC.

The Freeway Service Patrol (FSP) is an incident management program implemented by Caltrans, the California Highway Patrol and local partner agencies to quickly detect and assist disabled vehicles and reduce non-recurring congestion along the freeway during peak commute hours. The first FSP program was piloted in Los Angeles, and was later expanded to other regions by state legislation in 1991. As of June 2007, there were thirteen participating FSP Programs operating in California, deploying over 350 tow trucks and covering over 1,650 (center-line) miles of congested California freeways.

The purpose of this research project was to evaluate the effectiveness of the Caltrans FSP program in reducing incident durations and removal of other obstructions that directly contribute to freeway congestion for Caltrans fiscal year 2006-2007. The project provides valuable information to agencies managing the FSP program so that resources are distributed within the various statewide FSP operations in the most efficient and cost-effective manner possible. The tools used and the operational performance measures provided by this research effort will significantly contribute on the ongoing agencies’ efforts to improve the efficiency and effectiveness of the FSP program.

The Freeway Service Patrol (FSP) is an incident management program implemented by Caltrans, the California Highway Patrol and local partner agencies to quickly detect and assist disabled vehicles and reduce non-recurring congestion along the freeway during peak commute hours.  The first FSP program was piloted in Los Angeles, and was later expanded to other regions by state legislation in 1991.  As of June 2012, there were fourteen participating FSP Programs operating in California, deploying over 350 tow trucks and covering over 1,750 (center-line) miles of congested California freeways.

The purpose of this research project was to evaluate the effectiveness of the Caltrans FSP program in reducing incident durations and removal of other obstructions that directly contribute to freeway congestion for Caltrans fiscal year 2011-2012.  The project provides valuable information to agencies managing the FSP program so that resources are distributed within the various statewide FSP operations in the most efficient and cost-effective manner possible.  The tools used and the operational performance measures provided by this research effort will significantly contribute on the ongoing agencies’ efforts to improve the efficiency and effectiveness of the FSP program.

Weaving sections are common design elements on freeway facilities such as near ramps and freeway to-freeway connectors. When the traffic demands exceed the capacity at weaving areas congestion may occur, which affects the operation of the entire freeway section. Traffic operational problems also may exist at weaving areas even when traffic demands are less than capacity because of the complexity of vehicle interactions, resulting in poor level of service (LOS) and potential safety problems. Existing procedures for the design and analysis of freeway weaving sections have several shortcomings, and their practical application often produces inconsistent results.

This report describes the work performed under PATH Task Order 6304. The objective of the study was to evaluate the existing weaving analysis procedures to determine under which conditions the “best available” tools are most effective. The HCM2000, Leisch and Level D methods were evaluated using field data from 36 weaving sections for a total of 189 data points of speeds and volumes. A weaving performance matrix was developed to assist in determining which method to be used for a given mix of design and operational characteristics in a weaving section.