While recent California legislative reforms grant jurisdictions greater flexibility to lower speed limits, evidence suggests that reductions in posted speed limits alone are insufficient to meaningfully reduce crash severity. This research brief examines how speed limit reductions, when paired with infrastructure design, enforcement strategies, and contextual land-use planning, can more effectively lower FSI outcomes. Aligned with the Safe System Approach, the countermeasure layers of roadway geometry, lighting, bicycle-specific infrastructure, and enforcement shape driver behavior and...
In the US, speed limit setting (SLS) procedures have historically relied on driver-behavior-based methods, such as the 85th percentile speed, which are considered objective and allow for consistent application. However, this approach has notable shortcomings, including drivers’ tendency to underestimate their speeds, speed creep, and insufficient consideration of vulnerable road users, which may conflict with the Safe System Approach and Vision Zero initiatives endorsed by the USDOT (US Department of Transportation). In contrast, context-sensitive approaches, which classify roads...
UC Berkeley SafeTREC has released the California Traffic Safety Survey 2025. The study was led by Ewald & Wasserman Research Consultants (E&W) and conducted on behalf of the California Office of Traffic Safety (OTS) and SafeTREC. The California Traffic Safety Survey has been conducted annually since 2010, and this year's survey was conducted...
UC Berkeley SafeTREC is excited to share an update and refresh to our Safe System Approach toolkit, including new strategies, easier navigation, and more!
There’s a statistic that sticks in the minds of many who work on traffic safety issues: The U.S., among wealthy nations, has the highest rate of road traffic fatalities. People in the U.S. are nearly three times more likely to die in a car crash than people in Australia, and six times more likely than in Sweden.
For Julia Griswold, this troubling fact should be front of mind for everyone, whether they are drivers, cyclists, pedestrians or transportation planners. Griswold runs UC Berkeley’s...
Want to implement lower speed limits in your community? Watch the SafeTREC, Caltrans, and Rock Miller, PE "Toolkit for Safe Speed Limit webinar" SafeTREC to learn how to get started.
This Toolkit does not constitute a standard, specification, or regulation. This Toolkit is not intended to replace the existing Caltrans mandatory or advisory standards and is not intended to be a substitute for engineering knowledge, experience or judgment. This Toolkit promotes better access to helpful information and concepts from various agencies and organizations. UC Berkeley and Caltrans acknowledge the existence of other practices and provide this Toolkit for reference and direction for those responsible for making professional engineering or other design...
