Jurisdiction – Beck et al. (2018)

Study Reference:

Beck, K. H., Fell, J. C., & Kerns, T. J. (2018). Evaluation of Maryland's state police impaired driving reduction effort (SPIDRE). Traffic Injury Prevention, 19(4), 339-344.

Location in the Matrix; Methodological Rigor; Outcome:

Jurisdictions, Focused, Proactive; Moderately Rigorous; No evidence of effect

What police practice or strategy was examined?

The study evaluated the State Police Impaired Driving Reduction Effort (SPIDRE) program. A team of seven Maryland State Police officers were selected and dedicated to this campaign to conduct high-intensity DUI enforcement in data-driven locations (hot spots) where DUI crashes had been more likely to occur. The enforcement efforts were accompanied by media announcements that promoted this enforcement effort. The program occurred in Baltimore County in May 2013 and again in September and October 2013. After those three months, the team was relocated to other counties for various periods of time ranging from 2 to 3 months.

How was the intervention evaluated?

Data on alcohol-related crashes, arrests, and adjudicative outcomes of those arrests along with public opinion and bar patron surveys were used to compare counties with and without the SPIDRE program. The evaluation period extended from 2010 to 2016 in monthly intervals. ARIMA time-series analyses were used to detect whether there was a significant change in trends over time.

What were the key findings?

There was no significant reduction in alcohol-related crashes as reported by the police associated with the SPIDRE program. The study also constructed a ratio of single-vehicle to multiple-vehicle crashes as a proxy for impaired-driving crashes to account for underreporting of impaired drivers by police. The authors found that the ratio decreased significantly in the SPIDRE counties but not in the non-SPIDRE counties, suggesting indirect evidence for a crash reduction effect. The non-SPIDRE counties also experienced a significant decrease in DUI arrests during the evaluation period compared to the SPIDRE counties. Further, the arrests made by the SPIDRE team resulted in a significantly higher rate of positive adjudicative outcomes than arrests made by non-SPIDRE officers in those counties where the SPIDRE team operated. There was no evidence that the public was more aware of DUI enforcement efforts in the SPIDRE counties than non-SPIDRE counties.

What were the implications for law enforcement?

The authors suggest that the program may have lacked sufficient duration and intensity to achieve a reduction in alcohol-impaired driving crashes. But the program may have prevented a downward trend in DUI arrests and achieved higher quality arrests resulting in more positive adjudicative outcomes. The authors suggest that the SPIDRE program should last for at least 9-12 consecutive months to be effective.

Where can I find more information about this intervention, similar types of intervention, or related studies?