The “Buzzed” Driver: Drunk Enough to Matter?

By Dirk Hanson 06/22/11

Recent study argues for near-zero tolerance in blood-alcohol levels for drivers.

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One might be too many.
Photo via thinkstockphotos

Do you believe in statistics? We here at The Fix like to see the math, even if we’re not remotely equipped to do the math. However, it’s a habit that puts us in the way of a lot of bad news. Case in point: A just-published study in the journal Addiction, by sociologists at the University of California, San Diego, which lays out the numbers pertaining to traffic accidents and alcohol. As a society, we think we know what we’re doing when it comes to drunk driving—we’ve set a firm limit of 0.08% blood-alcohol content (BAC), and that settles it.

Except that 0.08% is a magic number—we might as well have pulled it out of a hat, according to David Phillips and Kimberly M. Brewer, co-authors of the study. Germany has settled on 0.05%. Does that mean Germans, overall, are safer on the highways than Americans? And what to make of Sweden, where officers of the law will pull you over and take you to jail if you test at 0.02%, a percentage which is just about exactly one drink shy of being a requirement for total abstinence behind the wheel? (A number of other countries are experimenting with the 0.02% standard as well.)

We’ll let the study authors deliver the unfortunate news: “Accident severity increases significantly even when the driver is merely ‘buzzed,’ a finding that persists after standardization for various confounding factors.” It doesn’t matter, they say, if it’s the weekend, or summer, or a particular day, or a particular month—the statistics are grimly the same. “The severity of life-threatening motor vehicle accidents increases significantly at blood alcohol concentrations (BACs) far lower than the currently US limit of 0.08%,” they write. Thanks a lot, killjoys.

The study is robustly based on crunching the data in the Fatality Analysis Reporting System (FARS), which covers fatal car accidents in the U.S. from 1994 to 2008. That’s a total of about 1.5 million deaths, by the way. “Accidents are 36.6 percent more severe even when alcohol was barely detectable in a driver’s blood,” according to Phillips. Even at a BAC of 0.01, there were more serious injuries than at 0.00. This is astonishing, if it proves true in further studies. The sociologists believe that the answer is threefold: Buzzed drivers “are more likely to speed, more likely to be improperly seat-belted and more likely to drive the striking vehicle,” all of which tend to result in more severe collisions. Naturally, Phillips advocates lowering the legal limit in America.

What this study claims is that there is no safe level of alcohol in the blood, when it comes to operating a motor vehicle. Statistically, you are always at elevated risk of serious accidents if any amount of alcohol is detectable in your blood. That’s a depressing thought, whether you are a driver, a passenger, or a pedestrian. Or will we just push these findings into the ditch, and drive on?

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Dirk Hanson, MA, is a freelance science writer and the author of The Chemical Carousel: What Science Tells Us About Beating Addiction. He is also the author of The New Alchemists: Silicon Valley and the Microelectronics Revolution. He has worked as a business and science reporter for numerous magazines and trade publications including Wired, Scientific American, The Dana Foundation and more. He currently edits the Addiction Inbox blog. Email: [email protected]