Even slight consumption of alcohol causes physiological
stress and impairs the driver's ability to keep the vehicle
centered in the lane, according to a study at Ben-Gurion
University.
The study tested drivers' physiological condition and gauged
driving proficiency and the driver's ability to maintain
driving proficiency despite paying a "physiological toll" --
changes in nervous system activity that cause a decrease or
increase in levels of mental stress and alertness.
The study focused on evaluating physiological stress in
performing driving tasks and the correlation between
physiological stress, performance indexes and the driver's
feeling on roads with varying levels of complexity (straight
roads versus curvy roads). The researchers also assessed
these categories when the subject was under the influence of
alcohol as well as the efficacy of energy drinks in delaying
fatigue among drivers.
The experiments were carried out in a laboratory where the
front part of a family car was attached to a driving
simulator and the surroundings were laid out to mimic natural
driving conditions. The computerized simulator controlled the
feel of the steering wheel, brake pedal, gas pedal and
driving scenarios programmed for various experiments.
The results revealed a dramatic decrease in heart-rate
variation while driving compared to resting. The ability to
maintain driving proficiency over time despite the difference
in driving demands was manifested in differences in
physiological stress.
"Veering from the center of the lane was found to be
sensitive to both levels of alcohol," said Dr. Adi Ronen.
"Veering under conditions of steering-wheel vibration was
found to be sensitive to high levels of alcohol alone whereas
speed changes were not found to be sensitive to the two
levels of alcohol. Variations in heart rate were found to be
sensitive to differences in mental stress between driving and
resting in the control experiment, sensitivity that
disappears following alcohol consumption. The subjects were
found to be less alert in the driving phase only after
drinking a large amount of alcohol in comparison with the
control experiment."
