Research Team: Offer Grembek (lead), Katherine Chen, Dillon Fitch, Brian D. Taylor, and Yu Hong Hwang
UC Campus(es): UC Berkeley, UC Davis, UCLA
Problem Statement: While California’s transportation system serves to provide mobility, it can be developed under the framework of a safe system with a goal of eliminating severe and fatal injuries. Providing a safe transportation system is both a moral and economic imperative. The road safety toll in 2017 claimed the lives of 3,602 Californians. The corresponding total cost of crash-related deaths in California was estimated to be $4.48 billion in 2013 and growing. To develop a safe transportation system, it is necessary to effectively harness all of the core protective opportunities provided by the system. This includes the street design and operations, user behavior, vehicle design, protection systems, and emergency response. The common thread across these layers is speed. This is directly driven by the quadratic relationship between velocity and kinetic energy, and the necessity to provide safe and structured dispersion of kinetic energy at the onset of safety-critical events. The state has an opportunity to redefine the role of speed management as part of a safe system through the Zero Traffic Fatalities Task Force (ZTFTF) formed in response to AB 2363.
Project Description: This research synthesis consists of a set of white papers developed to inform the work of the Zero Traffic Fatalities Task Force. The Task Force was formed in 2019 by the California State Transportation Agency in response to California Assembly Bill 2363. This report addresses the following critical issues: the relationship between traffic speed and safety; lack of empirical justification for continuing to use the 85th percentile rule; why we need to reconsider current speed limit setting practices; promising alternatives to current methods of setting speed limits; and improving road designs to increase road user safety.