Article Summary
An AAA Foundation study examining six cities found mixed and inconsistent results when police-motorist interactions declined, with some jurisdictions experiencing increased serious and speed-related crashes while others showed no significant safety changes, suggesting that reduced police stops do not have a uniform effect on traffic safety outcomes.
- Study Sites: AAA Foundation analyzed traffic data from six cities: Nashville, Philadelphia, and Minneapolis (major declines in police stops) and Charlotte, Chicago, and Saint Paul (smaller declines)
- Mixed Crash Results: Minneapolis and Philadelphia showed significant increases in fatal, serious injury and speed-related crashes, while Nashville reported no major increases despite substantial reductions in police stops
- No Consistent Pattern: The three cities with fewer changes in traffic stops also showed inconsistent outcomes, with some experiencing increased serious crashes while reporting decreased overall police-reported crashes
- Confounding Factors: Results could not be entirely separated from other factors including the COVID-19 pandemic, limiting the study's ability to draw conclusive causal relationships
- Key Finding: In some case-study cities, increases in serious and speed-related crashes coincided with reductions in police-motorist interactions, but the relationship remains unclear and jurisdiction-specific
The AAA Foundation for Traffic Safety has released a new study examining the effects of reduced police-motorist interactions on key traffic safety outcomes, showing an inconsistent relationship between police–motorist stops and safety outcomes.
Jurisdictions have increasingly adopted policies that limit traffic stop interactions between law enforcement and motorists, and while the AAA Foundation noted that deprioritizing pretextual stops is usually associated with an increased focus on public safety, existing studies on the impact of policy change on safety outcomes are limited, with available data suggesting that policies reducing police–motorist interactions do not have a negative effect on public safety.
According to the AAA Foundation, selected jurisdictions for the study included Nashville, TN; Philadelphia, PA; and Minneapolis, MN, for their substantial and continuous decline in police-motorist interactions and Charlotte, NC; Chicago, IL; and Saint Paul, MN, for their lesser change in traffic stops.
Data from each site were collected on crashes of various severity and analyzed using models that accounted for patterns such as seasonal cycles and long-term trends, among other factors.
The study results indicated that two of the three jurisdictions with the larger, more sustained decline in police-motorist interactions had increased crashes, particularly more severe or speed-related ones.
Minneapolis demonstrated significant rises in fatal and serious injury crashes and known-injury crashes. In addition, the results also suggested a possible significant increase in speed-related crashes.
Philadelphia demonstrated significant increases in fatal and serious injury crashes and speed-related crashes; however, the jurisdiction also had slight reductions in known-injury and total police-reported crashes.
Traffic patterns in Nashville did not report significant increases in fatal and serious injury, known-injury, or speed-related crashes, although data showed a small increase in total police-reported crashes. Of these three sites, Nashville was the only jurisdiction whose entire study period pre-dated the COVID-19 pandemic, noted the report.
Furthermore, the three other jurisdictions with fewer changes in traffic stops also did not demonstrate a consistent pattern of crash outcomes.
In Charlotte, traffic patterns showed a small but statistically significant increase in speed-related crashes in addition to a small but statistically significant decrease in police-reported crashes. Traffic patterns in Chicago demonstrated a significant increase in fatal and serious injury crashes with a decrease in all police-reported crashes, while Saint Paul also had a significant increase in fatal and serious injury crashes, but a statistically significant decrease in known injury crashes and speed-related crashes, the report summarized.
The AAA Foundation also noted that results could not be entirely separated from other occurring factors, including the COVID-19 pandemic. As such, the study's mixed results could not conclusively demonstrate that reductions in police–motorist interactions affect crash rates. Yet, the AAA Foundation concluded that the results suggest that, in some case-study cities, increases in more serious and speed-related crashes coincided with the reductions in police–motorist interactions.
The full report can be downloaded and read here.
