Data from four merge locations in northern California and Toronto, Canada unveil a notable feature of driver turn taking. We have observed that queued vehicles from the on-ramp and freeway traffic streams enter a congested merge in some (nearly) fixed ratio, independent of the merge outflow. Drivers in competing traffic streams thus enter the merge by adopting some definite turn-taking behavior and this behavior is not influenced by the severity of the exogenous flow restriction from downstream. The findings validate part of an existing theory of merging traffic and should be considered when developing any new such theories.

Freeway service patrol (FSP) is an incident management measure designed to assist disabled vehicles along congested freeway segments and reduce congestion through quick detection, response, and removal of accidents and other incidents on freeways. A two-year demonstration project has been proposed to extend FSP service to big-rigs and other heavy vehicles along the I-710 freeway. The report describes the work performed and the findings from the preliminary evaluation of the proposed I-710 Big-rig FSP demonstration project. The results show that the proposed FSP big-rig project will be cost-effective. Next steps in the ongoing research include detailed evaluation of the effectiveness of the FSP service based on field measurements throughout the two-year demonstration, and development of operational procedures for implementing big-rig FSP service to other freeway routes.

The Bay Area Incident Response System (BAIRS) is an integrated Web and GIS based incident tracking system that provides tools to improve California’s Department of Transportation (Caltrans) incident management capabilities. Currently, BAIRS aids District 4 Maintenance respond to and track over 33,000 incidents per year throughout the San Francisco Bay area.

The report presents the findings from the evaluation of the BAIRS system based on field data on incidents and traffic conditions. Through the implementation of BAIRS, incident response and clearance times were reduced by about 15%. Incident related delays were reduced by 210,000 vehicles-hours annually. The estimated BAIRS benefit-cost ratio is 5:1 based on the incident delay savings. Other benefits that are not reflected in the benefit-cost ratio include reduced fuel consumption and mobile emissions, and improved safety and access for emergency response vehicles.