California crash data is collected by several public agencies. Understanding these sources helps you interpret trends accurately and avoid drawing conclusions the data can't support.
SWITRS
The Statewide Integrated Traffic Records System (SWITRS), maintained by the CHP, collects collision reports from law enforcement agencies statewide. It is the foundational dataset for California collision research.
UC Berkeley SafeTREC / TIMS
The Transportation Injury Mapping System (TIMS), developed by UC Berkeley SafeTREC, maps and visualizes SWITRS data for research and public use. It is widely used to study geographic and temporal patterns in California collisions.
California Office of Traffic Safety
OTS publishes statewide safety priorities and performance metrics, helping frame where California focuses its safety efforts.
NHTSA
The National Highway Traffic Safety Administration provides national fatality data through FARS (Fatality Analysis Reporting System), useful for comparing California to national trends.
Interpreting the data
Counts alone can mislead. Trends are best understood alongside exposure data (vehicle miles traveled, population, and license counts). Reporting lags also mean recent years may be incomplete. Treat initial figures as preliminary.
