Three-hour experiment with drowsy drivers shows new results

Many drivers don’t realize how sleepy they are while driving, according to a new AAA research.

In the AAA experiment, participants had to drive 150 miles on a simulated highway with a speed limit of 65 mph.

Drivers could take breaks every 20 minutes in simulated rest areas. 50% of study participants did not take breaks. Nearly 40% took one break and 11% took two breaks. Among those who took breaks, approximately 40% indicated that the reason for the break was feeling sleepy.

The experiment showed that:

• Participants both underestimated and overestimated their levels of sleepiness compared to how they really were.
• When drivers reported low perceived levels of sleepiness, objective assessment suggested that 75% of them experienced moderate or severe sleepiness.
• Participants rated their sleepiness as low 25% of the time when an objective score indicated high sleepiness.

Throughout the time, participants were generally aware that they were experiencing drowsiness. However, according to the study, their perceived level of sleepiness was only “moderately correlated” with objective measures of sleepiness.

“The experiment provides insight into how drowsiness affects decision making during long night trips,” the study says. “The results demonstrate the need to help drivers improve their assessment of their sleepiness levels, as well as the need to educate drivers about the importance of paying attention to early signs of sleepiness and the importance of taking rest stops before they become very sleepy.”