A new trend is appearing in traffic violations across the country.
Police pull over drivers that seem to be driving drunk.
Laura Liddicoat is the supervisor for the Forensic Toxicology Program here in Wisconsin.
"The people appeared as though they were extremely intoxicated with alcohol, also had memory problems, but that the officers were completely baffled when alcohol was not involved because it was the drug Ambien."
Liddicoat says over the last 5 to 10 years, the sleeping aid Ambien has become one of the top 20 drugs found in an arrested driver's system.
In some cases, there are reports of sleep driving - a person waking in the middle of the night after taking Ambien, driving their car and claiming no memory of the incident.
"The brain is literally partly awake and partly asleep ... awake enough to perform very complex behaviors but not awake enough to monitor what's going on," says Dr. Mark Mahowald of the University of Minnesota Medical school.
But many experts, including Liddicoat, think a majority of the incidents come from taking the drug incorrectly, either mixing it with alcohol, or taking more than the recommended amount.
"But as far as the cases we've seen, the levels are indicative of misuse of the drug because Ambien is actually quickly eliminated from the blood. If taken as directed after 8 hours of sleep it will be gone from the blood stream."
Still others warn this may become a convenient defense for drivers caught by police.
Reports of people driving after taking Ambien are still rare.
Last year, doctors wrote 26 million prescriptions for Ambien.
Less than 100 users reported any sort of problem to the FDA.