Developing a Safe System Approach to Setting Speed Limits

Developing a Safe System Approach to Setting Speed Limits

Research Team

Offer Grembek
University of California, Berkeley

Funding Organization

California Department of Transportation (Caltrans). Task Number: 3896


Transportation professionals and policy makers in California are confronting a growing problem: increases in road traffic fatalities, injuries, and crashes despite a commitment to safety. In California, nearly 3,600 people die each year in traffic crashes and more than 13,000 people are severely injured. Collectively, these traffic crashes cost California over $53.5 billion, and speeding-related fatalities continue to represent a large portion of California’s total traffic fatalities. Recent research has demonstrated that speed increases crash risk in two ways: it increases the likelihood of being involved in a crash and it increases the severity of injuries sustained by all road users in a crash. 

In California, the relationship between speed and crash involvement has prompted calls from local governments to change the way that speed limits are set. In response, the Legislature passed Assembly Bill 2363, which directed the California State Transportation Agency (CalSTA) to convene a Zero Traffic Fatalities Task Force (ZTFTF) comprised of experts from across the state to brainstorm, evaluate, and recommend alternatives to the current speed-limit-setting methodology. 

This research project represents the first step towards developing a Safe Systems approach to setting speed limits, per CalSTA’s recommendation. The Safe Systems approach is used in other countries, most notably Sweden, the Netherlands, and Australia, and has been studied extensively. But it has yet to be implemented in North America. Changing how California establishes speed limits will be a significant undertaking that will require funding, time, and expertise to facilitate strategic decision and policy-making.