Drunk Driving: Even a Trace of Alcohol Is Dangerous on the Road, Says Study

Study shows drivers dangerous at 1/8 legal drinking level.

ByABC News
June 21, 2011, 5:56 PM

— -- Everybody knows drunk drivers are killers. But here's a startling finding by researchers at the University of California, San Diego:

Even a trace of alcohol, just enough to give a driver a "buzz," greatly increases the chances that the driver will be involved in an accident causing serious injuries and fatalities.

So how much is a trace? Anyone driving in the United States with a blood alcohol concentration of .08 percent is violating the law and considered drunk enough to be dangerous. But this study of nearly 1.5 million fatal accidents indicates that even .01 percent blood alcohol concentration is enough to increase the odds of a deadly accident. For many adults, that's less than half a beer.

"Accident severity increases significantly even when the driver is merely 'buzzed,'" according to the study, published in the current issue of the journal Addiction. The research, conducted by sociologists David Phillips and Kimberly M. Brewer, is based on federal statistics for fatal automotive accidents from 1994 through 2008.

The researchers were "initially startled" by their own findings, Phillips said during a telephone interview, "but then we discovered that people with such a low level of alcohol were behaving differently from sober drivers."

The authors said they believe this is the first study to use more than a decade of evidence from all U.S. counties and for all times of the day and all days of the week. They also believe their results are so conclusive that the legal limit should be lowered.

The U.S. limit of .08 percent is much more permissive than many countries. Some, including Brazil and Russia, have zero tolerance, so a driver in those countries is violating the law if he or she has even sipped a small glass of beer. Sweden, China, and Puerto Rico set the limit at .02 percent, and Japan outlaws drivers with .03 percent. Most countries fall between the United States and Brazil, setting the limit at around .05 percent.

The devastation caused by drunk drivers is well known in this country, and need not be repeated here, but the finding that even a small amount of alcohol increases the chances of a fatal accident is indeed sobering.

"Accidents are 36.6 percent more severe even when alcohol was barely detectable in a driver's blood," Phillips said in releasing the study. That begins at the .01 level, which is so low it would be difficult to detect short of a blood test, and increases steadily as the percentage rises.

Why would that little alcohol have such a deadly effect? The study, based on federal statistics collected after fatal accidents, reveals that "buzzed" drivers, as Phillips puts it, are more likely to speed, more likely to hit another vehicle, and less likely to be wearing a seat belt.

The findings are indeed startling, and in contrast with laboratory studies indicating that lack of coordination and impaired judgment begin to set in at two to three times the level required for a "buzz." But those studies are based on controlled experiments, not extensive records of real accidents.

Among the findings:

What it all adds up to, according to the researchers, is that alcohol, in any amount, is unsafe for drivers.