Police patrols for alcohol-related crashes: more rigorous evaluation needed

Driving vehicles after drinking alcohol is common, and has been shown to increase the risk of car crashes.1 There is a strong community perception that increased police patrols are effective in reducing dangerous driving practices such as drink–driving. A recently published review on the Cochrane Database of Systematic Reviews has examined the effectiveness of police patrols for reducing crashes and crash-related injuries.2

Police patrols were the main intervention examined in the review, and were defined as an increase in the number of officers or in the frequency and duration of patrols, with the intention of identifying impaired drivers via behavioral cues. Most included studies (91%) assessed increased patrols in combination with other programs such as media campaigns or special training for police officers. Therefore, it was generally not possible to evaluate the independent effect of each element of the intervention.

As the interventions were implemented in the community, studies designed to evaluate effectiveness at a community level were included in the review. Study designs included randomized trials, interrupted time series, and controlled before-and-after studies. The authors found many methodological problems with the …