Unsafe at any level: Very low blood alcohol content associated with causing car crashes

Even "minimally buzzed" drivers are more often to blame for fatal car crashes than the sober drivers they collide with, reports a University of California, San Diego study of accidents in the United States .

Led by UC San Diego sociologist David Phillips and published in the British Medical Journal group's Injury Prevention, the study examined 570,731 fatal collisions, from 1994 to 2011.

The researchers used the official U.S. Fatality Analysis Reporting System (FARS) database for the study, because it is nationally comprehensive and because it reports on (BAC) in increments of 0.01 percent. They focus particularly on "buzzed drivers," with BAC of 0.01 to 0.07 percent, and, within this group, the "minimally buzzed" (or BAC 0.01 percent).

Phillips and his co-authors find that drivers with BAC 0.01 percent – well below the U.S. legal limit of 0.08 – are 46 percent more likely to be officially and solely blamed by accident investigators than are the sober drivers they collide with.

The authors also find no "threshold effect" – "no sudden transition from blameless to blamed" at the legal limit for . Instead, blame increases steadily and smoothly from BAC 0.01to 0.24 percent.

Despite this evidence, "buzzed" drivers are often not punished more severely than their sober counterparts. In practice, Phillips said, police, judges and the public at large treat BAC 0.08 percent as "a sharp, definitive, meaningful boundary," and do not impose severe penalties on those below the legal limit. That needs to change, Phillips said. "The law should reflect what official accident investigators are seeing."

The researchers measured blame by looking at more than 50 driver factors coded in the FARS database, including such "unambiguous" factors as driving through a red light or driving on the wrong side of the road.

Many of the study's analyses take advantage of what the authors call "a natural experiment": two-vehicle collisions between a sober and a drinking driver. "Because the two drivers collide in exactly the same circumstances and at exactly the same time," they write, "this natural experiment automatically standardizes many potentially confounding variables," including weather and roadway conditions.

The findings are unequivocal, Phillips said. "We find no safe combination of drinking and driving – no point at which it is harmless to consume alcohol and get behind the wheel of a car," Phillips said. "Our data support both the National Highway Traffic Safety Administration's campaign that 'Buzzed driving is drunk driving' and the recommendation made by the National Transportation Safety Board, to reduce the legal limit to BAC 0.05 percent. In fact, our data provide support for yet greater reductions in the legal BAC."

Phillips noted that, although federal agencies recommend reducing the legal BAC limit below 0.08 percent, there has been very little research on the dangers of at very low levels of BAC. "We appear to be the first researchers to have provided nationwide evidence on traffic accidents caused by minimally buzzed drivers," he said.

More than 100 countries around the world have limits set at BAC 0.05 percent or below.

In calling on all 50 U.S. states to follow suit, NTSB Chairman Deborah A.P. Hersman said in a statement last spring: "Alcohol-impaired crashes are not accidents. They are crimes. They can – and should – be prevented. The tools exist. What is needed is the will."

Related Stories

Buzz kills: No amount of alcohol safe to drive

date Jun 20, 2011

In the United States, the blood-alcohol limit may be 0.08 percent, but no amount of alcohol seems to be safe for driving, according to a University of California, San Diego sociologist. A study led by David Phillips and published ...

US wants tougher drunk driving rule

date May 15, 2013

The US government wants states to crack down more on people driving under the influence of alcohol by lowering the permitted blood-alcohol limit.

Drunk driving can make holiday season deadly

date Dec 23, 2013

(HealthDay)—The holiday season is one of the most dangerous times of the year on U.S. roads. Between Thanksgiving and New Year's Eve, as many as 900 people nationwide could die in crashes caused by drunk ...

Designated drivers don't always abstain, study finds

date Jun 10, 2013

Maybe better call that cab, after all: A new University of Florida study found that 35 percent of designated drivers had quaffed alcohol and most had blood-alcohol levels high enough to impair their driving.

Recommended for you

Noise from fireworks threatens young ears

date Jul 03, 2015

(HealthDay)—The Fourth of July weekend is a time for celebrations and beautiful fireworks displays. But, parents do need to take steps to protect their children's ears from loud fireworks, a hearing expert ...

Many new teen drivers 'crash' in simulated driving task

date Jul 03, 2015

(HealthDay)—Around four in 10 newly licensed teen drivers "crashed" in a simulated driving test, suggesting that many adolescents lack the skills they need to stay safe on the road, according to a new study.

Insurer Aetna to buy Humana in $35B deal

date Jul 03, 2015

Aetna will spend about $35 billion to buy rival Humana and become the latest health insurer bulking up on government business as the industry adjusts to the federal health care overhaul.

Feeling impulsive or frustrated? Take a nap

date Jul 03, 2015

Taking a nap may be an effective strategy to counteract impulsive behavior and to boost tolerance for frustration, according to a University of Michigan study.

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.