If you booze, you lose: Even small amount of alcohol affects driving skills

For most drinkers, knowing when to say when occurs a lot quicker than they think. A study by Texas A&M University’s Center for Alcohol and Drug Education Studies shows that even a small amount of alcohol – in many cases, as few as one or two beers – can seriously affect judgment and driving decisions.

The study’s bottom line: Even if you’ve consumed very little alcohol, your decision-making skills are hampered more than you realize and the results could be deadly considering that nationally, 38 percent of all traffic deaths involve alcohol. In Texas, the rate is a staggering 49 percent, which leads the nation.

In a study titled Analysis and Evaluation of the Effects of Varying Blood Alcohol Concentrations on Driving Abilities, Texas A&M researchers led by Dr. Maurice Dennis tested 19 men and women of various ages and ethnic backgrounds performing driving skills at different blood alcohol concentrations (BACs).

Dennis and his team measured blood alcohol concentration throughout the driving test. Impaired driving skills were expected by those drivers who had reached illegal BACs, but the surprising results came from drivers who had small amounts of alcohol in their systems.

“In Texas and 20 other states, the blood alcohol concentration level to be legally intoxicated is .08,” Dennis says. “But we found that persons who registered a .04 – one-half the amount it takes to be legally intoxicated – had significant impairment in their driving abilities.

“In a nutshell, what it means is you don’t have to be staggering, fall-down drunk to have driving problems if you’ve drinking. A very small amount can affect your driving ability and especially the decisions you make while driving. A person may think to himself or herself, ’I’ve only had a couple of beers so I can drive okay,’ but their judgment can be severely affected and they don’t even know it.”

The study will be published in the next issue of The Chronicle of the American Driver and Traffic Safety Education Association. Helping to administer the driving tests were representatives from the Texas Department of Public Safety

Dennis says it doesn’t take much alcohol for many people to reach that dangerous .04 level. For a 150-pound man, it can be reached in as little as 1-2 beers, or just one beer for a 120-pound woman.

“Our tests showed that at .04, again one-half the level of legal intoxication, drivers had trouble with such skills as skid control, crash simulation and other maneuvering tests through stationary cones,” Dennis adds.

The driving tests were conducted during daylight hours, Dennis said, where vision is sharper than nighttime driving. “And you have to remember that most people drink and drive at night and fatigue can further hamper driving skills,” he notes.

Dennis said the test results have been recorded on a 12-minute VHS tape and is available statewide for driver education courses and law enforcement agencies.

Dennis study was funded by the Texas Department of Transportation.

Contact: Keith Randall, Office of University Relations, (979) 845-4644.