Volume 1, number 2

Sleeping at the wheel is criminal

Driving while tired caused between 41% and 54% of highway accidents in the United States, resulting in annual costs of 29 to 38 billion dollars. For Pierre Thiffault, whose doctoral thesis in psychology at Université de Montréal deals with factors predisposing drivers to hypovigilance, the matter is especially serious, because we don't pay enough attention to it. "We don't measure the state of fatigue as we can do with alcohol in the blood," he says. "But fatigue causes real carnage on the roads."

People who drive motor vehicles for a living are particularly at risk. "Truckers risk their lives as well as others' lives when they are behind the wheel," says the researcher. "In my thesis, I wondered if there could be a way to predict who, in a given population, might be likely to have problems of vigilance when driving."
As with any activity requiring attention, driving a car reveals a lot about our personality. "My hypothesis was that people who look for thrills and are more extroverted will have a tendency to fall asleep during prolonged driving sessions on roads that pose few challenges to the driver."

Experimentation was conducted at the Driving Simulation Laboratory under the direction of Jacques Bergeron, a professor in the Department of Psychology at Université de Montréal. Twice during a period of 40 minutes, 56 men took turns in a Honda Civic whose motor had electronic devices and a coating of wires instead of a piston. On the screen in front of them a road was displayed, which they had to follow without falling asleep. Only small gusts of wind forced them off their path. Vigilance was measured by sensors capable of recording up to 50 slight movements of the wheel per second.

In addition to providing conclusive evidence on endogenous factors of vigilance (the extroverted and thrill-seeking drivers are less vigilant on long distances than introverts who are not so hooked on thrills), the experiment showed that exogenous factors could reduce the risk of accidents due to fatigue. For example, a road lined with trees or lamp posts of the same size spaced at equal distances is more dangerous than a road with the same elements placed at random.

Researcher : Pierre Thiffault
Phone : (514) 343-6111, ext. 4610
Director : Jacques Bergeron, Department of psychology, 343-5811