(RxWiki News) Designated driver does not mean "the most sober person in the group," but for many people that has been the case. Designated driver really means "the sober person in the group."
In a recent study, researchers tested the breath alcohol levels of designated drivers leaving bars in college areas after 10:00 PM.
The results of the study showed that many of the designated drivers had been drinking and many were near or over the legal limit for driving.
"Use a sober designated driver."
Adam Barry, PhD, assistant professor of health education and behavior at the University of Florida in Gainesville, led an investigation into drinking among designated drivers.
In the US, drivers must have a blood alcohol content (BAC) of less than 0.08 percent to legally drive a vehicle.
Previous studies have shown slight driving impairment can happen in people with 0.02 percent BAC and moderate driving impairment can happen in people with 0.05 percent BAC.
For this study, the researchers interviewed 1,071 people as they were exiting bars or restaurants near a southeastern college. Each interview lasted for 3 to 5 minutes between 10:00 PM and 2:30 AM on Friday and Saturday nights in six different areas.
After the interviews, each designated driver allowed the researchers to obtain a breathalyzer sample to test for breath alcohol content.
Overall, 65 percent of the designated drivers were college students.
On average, non-designated drivers had a breath alcohol content of 0.04 percent and designated drivers had a breath alcohol content of 0.02 percent.
The researchers found that approximately 40 percent of designated drivers consumed some amount of alcohol that evening.
Of the 165 designated drivers, 65 percent did not drink any alcohol that evening, 17 percent consumed some alcohol and 18 percent had a breath alcohol content above 0.05 percent.
The majority (70 percent) of the designated drivers who had breath alcohol content levels above 0.05 percent were male and 45 percent were college students.
"Designated drivers who consume alcohol (regardless of level) or are selected because they are deemed 'least intoxicated' place both themselves and their passengers at greater risk for injury," wrote the study authors.
This study will be published in the July issue of the Journal of Studies on Alcohol and Drugs.
The National Institutes of Health Clinical and Translational Science Awards provided funding for this project. No conflicts of interest were declared.