Sleep Driving Defense Has Its Limits

By Robyn Hagan Cain on November 08, 2012 | Last updated on March 21, 2019

Sleep driving is a scary phenomenon, and it's becoming more common. More than 60 million Americans take prescription sleep aids, according to an ABC News report this year.

Sleep driving, however, isn't a defense to driving under the influence when a defendant voluntarily takes Ambien.

Terry Mathson was arrested for felony driving under the influence in 2008. As Mathson was a repeat offender, he was also slapped with charges for being a habitual traffic offender, driving with a suspended or revoked license, and driving a vehicle that was not equipped with a functioning ignition interlock device while his driving privilege was restricted.

On the night he was stopped, Mathson initially denied having consumed any alcohol or drugs but, upon further questioning, told Rocklin Police Officer Jeff Kolaskey that he had taken Vicodin pills -- prescribed for a back problem -- earlier that day. During the interview, he never mentioned having taken Ambien or zolpidem.

Kolaskey observed that Mathson had droopy, watery and glassy eyes, slow, slurred speech and a dry mouth. Although his verbal responses made sense, Mathson's speech was slurred and he was uneasy standing unassisted. Kolaskey, based on his observations, arrested Mathson for driving under the influence of drugs.

A blood test, administered nearly two hours after the stop, showed that Mathson had .13 milligrams per liter of zolpidem -- commonly known by the brand name Ambien -- in his system.

Mathson's defense? He wasn't criminally liable for DUI because he was sleep driving and, therefore, unconscious during the incident.

Prior to trial, Mathson filed in limine motions requesting standard or modified jury instructions on unconsciousness and involuntary intoxication, so the jury could determine whether he knew or had reason to anticipate that taking prescription Ambien could cause sleep driving.

The prosecutor filed a motion to exclude evidence of unconsciousness on the grounds that voluntary intoxication is not a defense to driving under the influence, and involuntary intoxication is not at issue where defendant intentionally took Ambien after having engaged in ambulatory behavior while asleep on prior occasions.

The court ultimately gave its own modified instructions on unconsciousness and involuntary intoxication. Mathson was convicted.

Mathson appealed, claiming that the trial court's modified instructions on unconsciousness, voluntary intoxication, and involuntary intoxication were erroneous. Though the appellate court found that the instruction on unconsciousness was flawed, it affirmed Mathson's conviction because the error was harmless.

With or without modified jury instructions, drivers under the influence of sleeping medications can find themselves in trouble. If you take DUI defense cases, you may want to look for a drug expert who can weigh in on sleep driving cases.

Related Resources:

Copied to clipboard