George, turning, now, to a graphic demonstration of what can happen when you take ambien and go driving hours later. It's the most popular sleeping pill in the u.S. It's been in the news because of... See More
George, turning, now, to a graphic demonstration of what can happen when you take ambien and go driving hours later. It's the most popular sleeping pill in the u.S. It's been in the news because of the kerry kennedy case. Lisa stark got behind the wheel to test out the dangers of driving on ambien or other sleeping pills. Reporter: It's been in the headlines before. And now again. This time, kerry kennedy, the daughter of robert kennedy. Last month after a hit and run, kennedy told police she may have accidentally taken the generic version of ambien. I remember getting on the highway. And then, I have no memory. Reporter: This new jersey woman also had no memory of driving, after taking ambien with some wine. In texas, a woman on ambien and alcohol plowed into a family in their yard, seriously injuring a toddler. She got probation. With 60 million annual prescriptions for sleeping pills in the u.S., There's increasing concern. We wanted to see firsthand just how easy it can be to have a serious accident if you pop a sleeping pill and drive. I took ambien and 30 minutes later climbed into the nation's most sophisticated driving simulator, at the university of iowa. Ambien acts fast. I was weaving all over the road and nearly hit a pedestrian. What we're seeing right now is very dramatic. Lisa is driving. But her vehicle is all over her lane. Reporter: After a nap, I try again. This time, 90 minutes in. Maximum ambien stupor. I feel barely awake, making wild turns. Sideswiping a big-rig. If this was an interstate, we could have a disaster on our hands. Reporter: How did I drive? Terribly? Reporter: Seriously? I hit a car? I'm certainly unsteady on my feet. Legs don't work quite as well. Even after four hours, I dozed through a red light. Let's face it, I should be sleeping. And in fact, I am. Now, this could happen on any sleeping pill. And all of them have warnings to take the pill and get seven or eight hours of sleep. And make sure you are fully awake before you drive. And the developer of ambien says that pill is perfectly safe when taken as directed. Lisa, did you remember much? It didn't look like you did. I remembered about half of it. That was dramatic. Very scary stuff. We appreciate it.
This transcript has been automatically generated and may not be 100% accurate.