Why Driving and Sleep Drugs Don't Mix

Aug. 14, 2012 — -- "I feel a little bit zombie-like, I have to admit."

On Tuesday's World News broadcast, correspondent Lisa Stark demonstrates the dangers of driving after taking sleeping medication. She traveled to the University of Iowa, home of the most advanced driving simulator in the country, to reproduce the experience of driving while under the influence of such medication.

Before the trial, she demonstrates abilities of a good driver within the simulator.

"You did fine in your test run," Omar Ahmad, director of operations for the National Advanced Driving Simulator tells her. "You were alert, you were paying attention, you were able to track, you were fairly well within the speed limit, your eye movements were consistent with someone who's alert, scanning the traffic around them as you should be."

Stark then takes a sleeping pill and undergoes another series of driving simulations. The first, at 30 minutes, demonstrates the effects during the medication's onset. Its effects are already noticeable.

"Lisa is now driving in the passing lane at a velocity of about 53 miles per hour in a 70 mph speed zone," reported Ahmad, in the control room at the time. "This is very dangerous."

"And now she's stopped blinking… She's really just zoned out," said Susan T. Chrysler, the simulator's director of research.

"Am I on the wrong side of the road?" Stark is heard asking. During this session she weaves along the interstate and occasionally veers onto the shoulder of the road. She runs at least one red light.

She undergoes another session at 90 minutes – at the drug's peak time of effect – during which time she nearly swerves into a truck. She narrowly misses one parked vehicle, but hits another. She falls asleep the minute the car is stopped. Asked to walk in a straight line, she is unsuccessful.

"I didn't feel that I was in control and I felt that I couldn't take in all the information on the roads and the car," says Stark. "I should not have been driving in that position."

Her last drive takes place four hours after taking the drug. Although her response times are improved, she continues to have seconds of zoning out, called "micro-sleeps."

"I think we can pretty safely say that we would recommend that she not drive a vehicle even at this point," said Ahmad. "Her reaction is indicative of somebody who's still somewhat impaired. "

Although the term "sleep driving" has been used to describe impaired driving due to misuse or abuse of sedative drugs like sleeping pills, the term technically refers only to cases when individuals drive while actually asleep or not fully conscious – much like sleep walking. These individuals typically drive in an impaired or unsafe manner.

First reported in 1996, sleep driving falls under the category of "complex behaviors" that can be side effects of certain sleeping pills. Other reported complex behaviors include sleep eating, sleep sex and sleep violence.

Such complex behaviors, however, are actually quite rare. In a review from 1992-2006 reports, researchers found a total of only 14 reports of sleep driving.