Researchers from the University of Florida have tested the extent to which alcohol impairs the driving abilities of different age groups using a computer simulation and have discovered that just one drink may impair the driving abilities of older people.
The team tested two groups comprising people aged 25 to 35 and people aged 55 to 70.
The participants' driving abilities were measured in a task that had them drive down a simulated winding 3-mile stretch of country road. Three computer monitors mimicked the windshield and side windows of a car, and a stereo played accompanying sounds.
The drivers controlled their simulated vehicle. Although the drivers would occasionally encounter another car as part of the simulation, there were no other distractions.
"These simulations have been used a lot in looking at older adults, and they have been used at looking how alcohol affects the driving of younger adults, but no one's ever looked at the combination of aging drivers and alcohol," said Alfredo Sklar, Co-Author of the study.
In the first test, the participants drove the simulated journey completely sober. The researchers recorded how rapidly the drivers adjusted their steering wheel, and their ability to stay in the centre of their lane and maintain a constant speed. In the next test, several days later, the participants were separated into groups.
Two groups were given an alcoholic drink strong enough to register breath alcohol levels of 0.04% and 0.065% respectively. A third group was given a placebo drink "misted with a negligible amount" of alcohol.
The participants then repeated the driving task.
In the younger group, the researchers were surprised to find that the alcohol had no measurable difference on their driving skills at all. But the driving of the older participants was adversely affected.
This study is the latest in a body of research from Professor Sara Nixon and her team examining how even moderate amounts of alcohol can affect older adults.
How much the results of these simulations, which were conducted in a laboratory, might apply to a real-life setting is debatable, though.
The researchers warn that just because there was no measurable difference in the performance of the younger drivers, it does not mean that these findings would apply to driving a real car after drinking alcohol. Professor Nixon points out that the laboratory task was much more simplified than real-world driving.
Also, the extent to which alcohol differently affects age groups is still being evaluated by the researchers. Further results are expected from the team on other simulations, which involve driving through a small town and a city populated with pedestrians and law-breaking motorists, among other obstacles.
Another component of the experiment that has yet to be analysed involved collecting electrophysiological data from the participants' brains. The data was collected using electrodes in caps that the subjects wore while driving through the simulation.
The findings of the study were published in the Psychopharmacology journal.