California Partners for Advanced Transportation Technology

This report documents the development of a preliminary specification for a transit bus frontal collision warning system, based on a system engineering approach. The research efforts included: 1) a literature review, 2) detailed analyses of the five-year safety records of a group of California transit properties to identify the causes of their safety problems, 3) an in-depth data collection and analysis from instrumented buses serving San Mateo County, CA, and 4) development and testing of three generations of transit bus frontal collision warning systems, incorporating enhancements to meet the needs identified by the bus drivers using the prototype systems. The analyses of the safety records and the combination of video and engineering data from the instrumented buses provide a uniquely rich pool of data for diagnosing transit bus safety challenges. The prototype warning systems incorporated innovations in signal processing to ensure that warnings are issued with high reliability and low rates of false alerts. Finally, the results of this work led to the definition of a preliminary specification for a frontal collision warning system for subsequent field testing.