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Status Report, Vol. 38, No. 2 | February 8, 2003 Subscribe

DWI checkpoints work, CDC review shows

Conducting regular sobriety checkpoints can significantly reduce crashes that involve drivers who have consumed alcohol. This is the major finding of an international review by the Centers for Disease Control of 23 studies of checkpoints. The researchers found that checkpoints reduce "alcohol-related crashes and associated fatal and nonfatal injuries ... . Despite differences across studies in design, periods of observation, and outcome measures evaluated, the results were generally consistent in direction and size."

Sobriety checkpoints reduced the crashes involving alcohol by about 20 percent, the researchers found. They pointed to the effectiveness of checkpoints that were conducted at the city, state, and national levels. Checkpoints conducted on both urban and rural roads were effective, the CDC reported.

The researchers reviewed studies of two types of checkpoints — those involving random breath tests at which every driver passing through is tested and those at which police must have a reason to suspect a driver has been drinking to demand a breath test. Both types proved equally effective in reducing crashes involving drivers who had consumed alcohol.

"Checkpoints are primarily about deterrence, and both kinds of checkpoints increase the perception among drivers that arrest is likely if they drive while impaired. The result is that drivers aren't as likely to drink and drive in the first place, and alcohol-related crashes are reduced," Institute chief scientist Allan Williams points out. "Checkpoints counter a driver's belief that he or she can drive well enough after drinking to avoid being apprehended. Seeing a checkpoint in progress or going through one reinforces in drivers' minds that enforcement has been stepped up and arrest is likely."

There's a perception in some quarters that checkpoints are less effective than other enforcement strategies because they don't yield as many arrests. "But this is missing the point. The main purpose is to deter alcohol-impaired drivers, and checkpoints do this very well," Williams says.

No recent progress on impaired driving

The percentage of fatally injured drivers who were impaired by alcohol has held steady in recent years. That's one of the trends visible in the latest crash death statistics.

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