Taking a taxi might be safer after all: Nearly 40% of designated drivers have guzzled down alcohol and most have blood-alcohol levels high enough to impair their driving, according to new research by the University of Florida.

A group of researchers interviewed and breath-tested over 1,000 bar-goers in the downtown bar and restaurant district of a major university town in the Southeast.

They found that of the designated drivers who had ingested alcohol, 50% documented a blood-alcohol level over .05% – the recently recommended new level for driving under the influence.

Adam Barry, an assistant professor of health education and behavior at UF, said:

“If you look at how people choose their designated drivers, oftentimes they’re chosen by who is least drunk or who has successfully driven intoxicated in the past — successful meaning got home in one piece … that’s disconcerting.”

The investigators recruited bar patrons as they exited bars between 10 p.m. and 2:30 a.m. among six Friday nights before home football games in the fall season of 2011. The mean age of the 1,071 people who consented to be tested was 28 years. The majority of them were white male college students – 10% were Hispanic, 6% were Asian, and 4% were African-American.

Participants completed a 3-5 minute interview regarding demographic data and alcohol-related behaviors, followed by the testing of their blood-alcohol content using a hand-held breath-testing instrument.

The findings, published in the Journal of the Studies on Alcohol and Drugs, revealed that non-driving patrons had notably higher levels than the designated drivers, however 35% of the 165 self-identified designated drivers had been drinking alcohol.

Of the drivers tested, 17% had blood-alcohol levels between .02 and .049%, while 18% were at .05% or higher.

Just last month, the National Transportation Safety Board recommended all 50 states take on a blood-alcohol content cutoff at 0.05 compared with the 0.08 standard currently used to qualify as drunken driving. Additionally, the American Medical Association made the same recommendation in the 80’s.

Possible factors that could lead to designated drivers drinking include group dynamics and the belief that one or two drinks will not impair driving skills.

Previous studies suggest that designated drivers might drink because the group did not choose a driver before starting to drink. Barry also believes that it is difficult for anyone to correctly assess their own sobriety.

Barry explained, “That’s the insidious nature of alcohol — when you feel buzzed, you’re drunk.”

The research points out that there is no universal definition of a designated driver. Although other researchers in the U.S. say that drivers should completely abstain, other researchers from around the world think they can drink as long as their blood-alcohol level is under the legal limit.

The limit in the U.S. is much higher than in most other nations. At .08%, it is one of the highest legal limits of any developed country.

Countries such as Denmark, Greece, and Finland use the .05 level; Sweden and Russia are at .02; and Japan has a zero percent tolerance.

In 2010, a report by SAMHSA (Substance Abuse and Mental Health Services Administration), suggested that 30 million Americans have admitted to driving while drunk. Figures showed that 13.2% of Americans aged 16 or over have driven under the influence of alcohol and 4.3% did so while intoxicated with illegal drugs during a 12 month period.

Written by Kelly Fitzgerald