Marijuana and DUI: What to know before you get behind the wheel

Marijuana and DUI: What to know before you get behind the wheel

"A few years back, they were a rarity; but it's really started to increase over the past couple years since we've had the passage of medical marijuana laws here in Nevada." DUI attorney John Stephenson said he's seeing more DUI cases involving marijuana than ever before.

Many people are familiar with the laws regarding driving under the influence of alcohol; but when it comes to pot, Stephenson said, "A lot of times, people just don't know what the law is."

Nevada law states the legal limit for drivers is 2 nanograms of marijuana per milliliter of blood (2 ng/mL). The legislature dictates that amount, as well as the legal limits for other controlled substances.

It's important to note that under current Nevada law, the legal limit only applies to people with medical marijuana prescriptions. Any one else caught driving under the influence of cannabis could lose their license and/or face misdemeanor charges.

The legal limit for driving under the influence of cocaine or heroin is 50 ng/mL. For amphetamines, the limit is 100 ng/mL. Again, this is compared to 2 ng/mL of marijuana.

How do nanograms translate to the amount of time a marijuana user should wait to drive? Stephenson said there isn't a clear answer. "You just don't know. Everybody's body processes marijuana differently."

In fact, no one seems to have a definitive answer about how long is safe to wait before getting behind the wheel. Nevada Highway Patrol Sgt. Eddie Bowers said, "It's too hard to pin own how much (marijuana) is going to make you DUI."

Bowers is one of many law enforcement officials already prepared to test drivers who may be driving under the influence of cannabis. He is among at least 20 other NHP officers across Nevada who use a machine called the Draeger Drug Test 5000. Officers keep the portable device in their patrol cars to test oral fluid samples for seven different kinds of drugs.

Within eight minutes, Bowers said the simple test can detect methamphetamine, amphetamine, benzodiazepines, cocaine, cannabis, methadone and opiates.

He said, "They hold [the cartridge] under their tongue for about a minute to a minute and a half... They hand it back to the officer and then the officer just merely places it inside the machine and starts the test."

The Draeger does not tell officers how much of a substance is in your system, but rather shows a positive or negative result. Bowers said he Draeger won't detect trace amounts of marijuana. He said if someone consumed cannabis two weeks prior to the test, it would not come back positive.

Unlike a breathalyzer test, drivers are not required to submit at oral fluid test in the state of Nevada. Bowers said, "Somebody can say, 'no I'd rather not do that test' under no penalty." However, an officer still has the right to arrest a driver suspected of operating a motor vehicle under the influence.

"No one piece of the puzzle is the catalyst of somebody being arrested for DUI," Bowers said. "Not a preliminary breath test. Not a field sobriety test. Not the fact that they were driving poorly. It really is a totality of circumstances made up of many phases of detection."

After testing in the field, officers will likely take a suspect to a nearby facility to submit a blood or urine sample. Those tests will show if a suspect is above the 2 ng/mL limit for marijuana and the results are admissible evidence in court.

While you are allowed to refuse an oral fluid test, refusing to take a blood test carries an immediate penalty. Bowers said, "The DMV will revoke their driver's license for one full year."

Other law enforcement agencies are preparing for the potential passage of Question 2 as well. The Washoe County Sheriff's Office is sending its deputies through specialized training to better detect signs of driving under the influence.

Lt. Eric Spratley with the sheriff's office said, "Our officers are trained to look for indicators of impairment that start from an immediate traffic violation or some sort of roadway indicator such as not maintaining a lane, rolling through a stop sign, speeding, and in cases of marijuana, sometimes it's driving too slow."

Although there is no official guideline about how long you should wait to drive after using marijuana, the officials who spoke with News 4-Fox 11 all agreed on one thing: just like drinking alcohol, drivers should smoke responsibly.

DUI Attorney John Stephenson said, "If you feel at all intoxicated or you've smoked within the last two to three hours, don't drive. Just don't take the chance. It's not worth it."


This is one story in a series about the potential legalization of recreational marijuana. In the next installment, Olivia DeGennaro will look into how cannabis affects a user's health, compared to tobacco and alcohol. WATCH her story next Wednesday, July 13, 2016, on News 4 at 5 p.m.

Is there something you want to know about Question 2 or recreational marijuana? Connect with Olivia on Facebook or Twitter to submit your story ideas.

RELATED STORY: Question 2: How could recreational marijuana affect Nevada's economy?

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