Report

Given the multiple factors involved in police stop and enforcement decisions, it is beneficial for agencies to identify and better understand trends and patterns to enhance their ability to interact with the public safely and fairly. The Pennsylvania State Police (PSP) renewed their traffic stop data collection effort in 2021. This report documents the findings from statistical analyses of data collected by PSP troopers during all member-initiated traffic stops in 2022. The PSP data collection effort is one of the most comprehensive in the country and includes data fields related to stop characteristics, reason(s) for the stop, driver characteristics, enforcement outcomes, vehicle characteristics, and characteristics of the trooper who made the stop.

In this report, we discuss the results of our analyses of post-stop outcomes (e.g., warnings, citations, arrests, and discretionary searches). The findings show that legal variables are the strongest predictors of all post-stop outcomes. Once other driver, vehicle, and situational characteristics are considered, there are no detectable substantive racial/ethnic differences in warnings, citations, and arrests. Discretionary searches are the only post-stop outcome with statistically significant and substantively small or moderate findings of racial and ethnic disparities that are not explained with available measures. More than half of all discretionary searches result in the seizure of contraband.

Informed by the traffic stop data analyses, NPI research team provides four broad recommendations designed to improve data collection, further examine the patterns and trends in traffic stop enforcement, identify opportunities to enhance training, and strengthen accountability.