With summer comes bon fires, beach parties, barbecues and music festivals, and with those types of events, alcohol sometimes comes too. The typical safety advice in these types of situations always starts with the same important tip: designate a sober driver so you and yours can get home safely when the festivities have ended. But is having a designated driver really a guarantee that your wheelman will be clearheaded at the evening’s conclusion? Far from it, according to a new study that finds that approximately 40% of so-called “designated drivers” actually end up drinking anyhow.

The study is particularly troubling considering the statistics from MADD, which state that 28 people die per day in the U.S. as a result of drunk driving crashes. Also, 300,000 incidents of drinking and driving occur daily.

Designated = Sober? Not So Fast

The study was conducted by researchers from the University of Florida in Gainesville, who examined bar patrons over the course of six different nights in a Southeastern college town. The study authors interacted with nearly 1,100 individuals, most of them male caucasian college students, giving them alcohol breathalyzer tests and interviewing them as they exited bars between the hours of 10:00 PM and 2:30 AM. Roughly 165 of the subjects interviewed described themselves as designated drivers for the evening.

The researchers gathered some surprising data:

• 17% of the “designated drivers” had a blood alcohol level between 0.02% and 0.049%.
• 18% of the “designated drivers” had a blood alcohol levelabove 0.05%.
• An additional 5% had at least some alcohol detected in their blood.

Legal Limits and Alcohol Impairment

Most states have a legal maximum blood alcohol content of 0.08% for drivers. However, the U.S. National Transportation Safety Board recently issued a recommendation stating that states should change the legal limit to 0.05% instead – about two drinks for a man weighing 160 pounds, or one drink for a woman weighing 120 pounds. Many European countries, such as Greece, Finland and Denmark, have already adopted the stricter policy.

According to researchers, drivers begin to lose their skills and coordination when their blood alcohol content reaches just 0.02%. Impairment becomes more severe and noticeable at 0.05%. However, even at the current U.S. legal limit of 0.08%, some drunk drivers appear sober until given field sobriety tests.

Buzzed Driving is Drunk Driving

Many self-proclaimed “designated drivers” may feel that they’re capable of driving just because they don’t feel outright drunk, believes Adam Berry, one of the lead researchers behind the study. However, Barry says that this isn’t an accurate test because alcohol impairs driving skills before it even creates the feeling of a “buzz.” In addition, the effects of alcohol take several minutes to kick in. A designated driver who finishes his or her only drink immediately before leaving the bar might not feel the effects of the alcohol until they’re five or more miles down the road.

Making matters worse are the facts that designated drivers are typically called upon at night, when visibility is low, and that passengers who require a designated driver can often be obnoxious and distracting. According to Barry, the only safe way to be a designated driver is to abstain from all intoxicants for the evening.

The Bottom Line

According to a new study by researchers at the University of Florida, up to 40% of self-identified “designated drivers” are actually too impaired to safely drive by the time they leave the bar. Nearly 20% had blood alcohol levels upwards of 0.05%, the legal limit in many European countries. However, the study results may have been slightly skewed as researchers only looked at bars and nightclubs in a single city with a largely homogenous subject pool.

The full text of the study is available online in the Journal of Studies on Alcohol and Drugs.