UC ITS Research Reports
Available online at: https://escholarship.org/uc/item/5hg5m6sm
Grembek, Offer, Katherine Chen, Brian D. Taylor, Yu Hong Hwang, Dillon T. Fitch, Sonia Anthoine, Bingchu Chen, Salvador Grover (2020) Research Synthesis for the California Zero Traffic Fatalities Task Force. Institute of Transportation Studies, University of California, Davis, Research Report UCD-ITS-RR-20-58
This research synthesis consists of a set of white papers that jointly provide a review of research on the current practice for setting speed limits and future opportunities to improve roadway safety. This synthesis was developed to inform the work of the Zero Traffic Fatalities Task Force, which was formed in 2019 by the California State Transportation Agency in response to California Assembly Bill 2363 (Friedman). The statutory goal of the Task Force is to develop a structured, coordinated process for early engagement of all parties to develop policies to reduce traffic fatalities to zero. This report addresses the following critical issues related to the work of the Task Force: (i) the relationship between traffic speed and safety; (ii) lack of empirical justification for continuing to use the 85th percentile rule; (iii) why we need to reconsider current speed limit setting practices; (iv) promising alternatives to current methods of setting speed limits; and (v) improving road designs to increase road user safety.
Keywords: Vision Zero, 85th percentile speed, highway safety, speed limits, safety engineering, crash risk forecasting, traffic crashes, highway design