The blood-alcohol limit in the U.S. is 0.08% — a cutoff that implies that any blood-alcohol content south of 0.08% is safe, or at least not illegal.
But a new study published in the journal Addiction suggests that there is no such thing as a safe BAC, and that driving after consuming even a small amount of alcohol — just one beer, for instance — is associated with incapacitating injury and death.
The safety of “buzzed” driving has been on the minds of the public recently, in light of the death of MTV’s Jackass star Ryan Dunn, 34, who crashed his car on a highway in Chester County, Pa., at high speed, also killing his passenger, Zachary Hartwell, 30. Hours before the crash, Dunn posted a photo on his Twitter account showing him drinking. The manager of a local bar, Barnaby’s of America, told the Philadelphia Inquirer that Dunn had been in late that night with friends, but didn’t seem drunk when he left.
It’s unknown whether or how much alcohol played a role in Dunn’s crash. But the new study by two demographers at the University of California, San Diego, found that drivers who consumed even a single drink before getting behind the wheel were more likely than sober drivers to get into car crashes; those accidents were also on average more severe than those involving sober drivers.
David Phillips and Kimberly M. Brewer of UCSD’s sociology department looked at accident and injury data from the Fatality Analysis Reporting System database, which tracks every car accident in the U.S. involving at least one fatality; between 1994 and 2008, those accidents involved 1,495,667 people. The researchers used FARS because it includes drivers’ BAC and logs car crashes occurring in all U.S. counties, at all times of day, every day of the week.
The researchers focused on the association between drivers’ BAC and the severity of car crashes. By definition, accidents included in FARS are severe and the researchers were not able to examine injuries that occurred in non non-fatal accidents. Instead, they calculated the ratio of severe to non-severe injuries in FARS crashes and compared that to drivers’ BAC.
What the authors found was that the severity ratio increased significantly even when drivers were merely buzzed. A BAC of just 0.01% — about the equivalent of one light beer for a 180-lb. man over the course of two hours — was associated with accidents that were 37% more severe than those involving completely sober drivers.
Car crashes involving a driver with a BAC of 0.01% resulted in 4.33 severe injuries for every minor injury; in crashes involving sober drivers, there were an average 3.17 severe injuries for every minor injury.
Why do buzzed drivers have more dangerous accidents? In large part because they are more likely to speed, less likely to wear a seat belt and more likely to be driving the “striking vehicle,” compared with sober drivers, the study found.
