Sobriety Checkpoints, Police Patrols May Not Reduce Drunk Driving Incidents

• Oct 11, 2008

Although communities commonly use sobriety checkpoints and increased police patrols to detect drivers under the influence of alcohol, a new review by the Colorado Injury Control Research Center and the Colorado School of Public Health reports there is not enough evidence to say definitively that these efforts to cut down the number of accidents and deaths from drunk driving.

"Increased police patrols might be effective, but we do not yet have enough evidence to prove that they are," said Cynthia Goss, lead reviewer.

The aim of the systematic review--which is titled "Increased police patrols for preventing alcohol-impaired driving" and was published in the current issue of The Cochrane Library, a publication of The Cochrane Collaboration--was to determine whether high-visibility efforts that target alcohol-impaired driving, such as increased police patrols, have any effect on injuries and car crashes. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing trials on a topic.

Alcohol-impaired driving is a common problem worldwide, according to the reviewers. They cite a U.S. survey in which 4.5 percent of adults reported having driven while impaired at least once in the last 12 months.

According to the Mothers Against Drunk Driving (MADD) Web site, In 2006, nearly 16,000 people in the United States died in alcohol-related traffic crashes.

The reviewers evaluated 32 studies, most conducted in the United States. In a majority of the studies, the specific intent of police interventions was to reduce driving under the influence (DUI). Some others aimed to reduce DUI and other traffic violations, such as speeding. Twenty-four of the 32 studies reported how often the increased police patrols occurred. This ranged from daily in seven studies, four to six days a week in four studies, to less frequently (holidays or sporadically) in seven studies. The average duration of the increased patrol intervention was 15 months.

Although most of the studies found that increased police patrols reduced traffic crashes and deaths, the reviewers concluded that the decreases might have been due to chance alone because of the small size of the studies, and that the weak or unclear quality of the studies means that their results might be unreliable or biased.

"Study quality cannot be separated from study results. A poor quality study can make the intervention look better--or worse--than it really is," Goss said. "We recommend that better quality studies be done because our review suggests that increased police patrols are promising as a way to reduce alcohol-impaired driving."

In contrast, MADD officials said that there already is proof that sobriety checkpoints indeed curb those who drive under the influence.

"Federal research from the Centers for Disease Control and Prevention shows that sobriety checkpoints reduce alcohol-related crashes and fatalities by up to 24 percent," said Laura Dean-Mooney, MADD national president. "Checkpoints are one of the most effective tools we have to deter drunk driving."