You may be safer calling a cab than relying on your friends after a night of drinking, new research suggests. Roughly 40 percent of designated drivers still imbibe when they go out, many to a level that would impair them behind the wheel, a new study finds.
To study the habits of designated drivers, researchers at the University of Florida in Gainesville went out into the field, spending six nights surveying bar-goers in an unnamed college town in the Southeast.
All told, the researchers interviewed and gave alcohol breath tests to 1,071 people, including 165 self-identified designated drivers, as they left bars between 10:00 p.m. and 2:30 a.m. Most participants in the study were white male college students.
The researchers found that 40 percent of the designated drivers had been drinking. What's more, 18 percent had blood alcohol levels of 0.05 percent or higher and 17 percent were between 0.02 and 0.049 percent.
Researchers say that driving skills start to diminish when a person's blood alcohol level hits 0.02 percent. By 0.05 percent, impairment is more obvious. Many other developed countries, such as Denmark, Finland and Greece, use a 0.05 blood-alcohol level as their cutoff mark for driving.
Last month, the U.S. National Transportation Safety Board recommended that states lower the cutoff for impaired driving from a blood-alcohol content of 0.08 to 0.05 percent. That could make driving illegal after one drink for a 120-pound woman and after two drinks for a 160-pound man, according to the Associated Press.
Study researcher Adam Barry, a University of Florida assistant professor of health education, suspects that designated drivers may think they are OK to get behind the wheel as long as they don't feel drunk. But a self-evaluation of sobriety is tricky, and the buzz is an inept measuring stick, because driving skills are already impaired before that feeling sinks in, Barry said.
Other factors can coalesce to make driving home more dangerous for designated drivers, such as a carload of distracting drunken passengers and dark nighttime driving conditions, Barry added. "If you're going to be a designated driver, you should abstain from alcohol use completely," he said in a statement.
The research is detailed in the July issue of the Journal of Studies on Alcohol and Drugs.
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