Evidence-Based Policing Matrix
Neighborhood – Josi et al. (2000)
Josi D. A., Donahue M. E., & Magnus, R. (2000). Conducting blue light specials or drilling holes in the sky: Are increased traffic stops better than routine patrol in taking a bite out of crime? Police Practice and Research, 1, 477-507.
Location in the Matrix; Methodological Rigor; Outcome:
Neighborhood, Focused, Proactive; Moderately Rigorous; Mixed findings
What police practice or strategy was examined?
The study assesses the impact of aggressive traffic enforcement on crime. For a period of 6 months, patrol officers in Savannah, GA increased traffic contacts by a minimum of 100% in experimental target areas. Aggressive enforcement focused on all possible violations of traffic laws, including speeding, seat belt violations, DUIs, and invalid licenses and registrations.
How was the intervention evaluated?
Aggressive enforcement (i.e., more traffic stops) in four experimental reporting districts was compared to routine enforcement in four control reporting districts. The size of these reporting districts varied from 10 to 20 blocks. Monitoring the number
of traffic stops per month in both areas permitted the research staff to compare the frequency of stops in the treatment areas before, during, and at the conclusion of the study. The dependent variables for this study consisted of selected Part I and selected Part II offenses (separated and aggregated).
What were the key findings?
The results for this study are mixed. In the aggregate, Part I offenses showed downward trends in the 4 experimental areas, accounted for by statistically significant drops in larceny and burglary. Part II offenses declined in each of the treatment areas but failed to show statistically significant decreases. Disaggregated Part II offenses indicated a statistically significant drop in simple assaults. Declines, however, also occurred for the control areas, where larceny also declined significantly.
What were the implications for law enforcement?
While the findings show some evidence that targeted traffic enforcement can reduce crime, the results are not conclusive.
Where can I find more information about this intervention, similar types of intervention, or related studies?