By Emily Owens and Emily Hope Anderson

We analyze 2.3 million stops made by the California Highway Patrol (CHP) in 2022 to better understand who is being stopped (or helped in non-enforcement stops), if there are racial and ethnic disparities in who is being stopped, and suggest possible strategies the CHP could use to reduce unwarranted disparities in stops while also promoting public safety. KEY FINDINGS: 1. As compared to 2019, there were fewer enforcement and non-enforcement stops made by the CHP in 2022. This is likely driven by changes in the number of California drivers and their behavior or by the number of CHP Officers, rather than a reduction in CHP enforcement effort. 2. The overall size of Black-White and Hispanic-White disparities in stop rates, benchmarked to non-enforcement stops, is about the same as it was in 2019. This is true both state-wide, and within individual CHP Divisions. 3. In 2022, CHP Officers were more likely to stop Black or Hispanic people for moving violations than White people. A Veil of Darkness test also suggests the potential presence of bias in stops for moving violations. 4. In 2022, 21% of the traffic enforcement stops made by the CHP were for non-moving violations. These stops for non-moving violations led to 35% of all serious contraband seizures by CHP Officers and 12% of DUI arrests. Officers are more likely to discover serious narcotics in searches following non-moving violations than in searches following moving violations. 5. Black-White and Hispanic-White disparities in stop rates for non-moving violations made a small contribution to overall disparities in stops rates. If the CHP did not make any stops for non-moving violations in 2022, Black-White disparities in stop rates would have been 2.9% lower, and Hispanic-White disparities would have been 2.2% lower.  RECOMMENDATIONS: 1. The CHP should consider further investigation into the quantity and specific type of contraband seized when conducting searches; this information is currently not included in RIPA data. This would allow for a more formal cost-benefit analysis of making stops for non-moving violations. 2. The CHP may want to consider increased use of technology in making stops for moving violations. Statistical tests suggest that stops made where speed information is gathered by radar, lidar, or airplane, are less likely to involve nonWhite drivers than stops made when a CHP Officer collects speed information by driving alongside or behind the potentially speeding car.   

Berkeley: California Policy Lab, 2024. 56p.