Just One Drink Could put Older Drivers at Risk

A single serving of wine may be enough to make drivers 55 or older a dangerous threat on the road, a study suggests.

Sara Jo Nixon, a professor in the departments of psychiatry and psychology at the University of Florida, and doctoral candidate Alfredo Sklar tested how drinking legally non-intoxicating levels of alcohol, less than 0.08 percent of total blood alcohol, affects the driving skills of two age groups: 36 people ages 25 to 35 and 36 people ages 55 to 70.

The researchers found that although neither age group imbibed enough alcohol to put them over the legal driving limit, just one drink could impair the driving abilities of older drivers.

Both groups began by completing a driving task sober. The task took the drivers down a simulated 3 miles country road, with driving sounds, a steering wheel, gas, brake pedals, and even side windows, to closely mimic a real driving scene. The drivers occasionally encountered oncoming cars but did not face any other distractions.

On a following day, the groups were further separated into even smaller groups. The first took a placebo while the second group's drink was strong enough to produce a 0.04 percent breath alcohol level. The third group's drink produced a breath alcohol level of 0.065. Participants then completed the same driving task they had previously performed sober. Researchers took note of the drivers' ability to maintain constant speed, remain in the center of their lane, and how quickly they adjusted their steering wheel.

The researchers found that in younger adults the alcohol consumption had no measured effect on their driving abilities, whatsoever. However, Nixon warned that the laboratory setting was simplified and that the absence of effects in the laboratory setting does not mean that young adult drivers' driving wouldn't be affected in normal real world conditions.

For the older drivers, the small, legal levels of intoxication affected their driving.

Based on the study findings published in the journal Psychopharmacology, the researchers hint that it may be time to reassess legal blood alcohol levels for all drivers.