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How long will THC remain in your system? Debate continues as more states legalize recreational pot

Marijuana Boom Oklahoma
Posted at 9:50 PM, Feb 15, 2021
and last updated 2021-02-16 00:33:59-05

PHOENIX — As marijuana increasingly becomes 'mainstream,' doctors, lawyers, and even lawmakers are still struggling to define how much is too much when it comes to impairing your judgment behind the wheel of a car.

With recreational marijuana sales starting last month, Arizona law enforcement agencies are preparing to see an influx of stoned drivers on roads and highways. According to numbers ABC15 has obtained from the Governor's Office of Highway Safety, that disturbing trend has already begun. Data shows an increase in the number of DUI's involving marijuana and other drugs on state roads.

So, how long should you wait after smoking or ingesting cannabis to drive? It's the million-dollar question yet to be defined by law in Arizona. Multiple experts ABC15 spoke to have an opinion, but none agreed.

Adam Cogswell, who works in the medical marijuana industry, said he had heard it's okay to drive 14 hours later, but he learned the hard way that marijuana was still in his blood after two DUI convictions in the last few years.

He was on his way to work at a dispensary when he received one of those violations. In body camera footage of one of Cogswell's arrests, Mesa police pulled him over for not coming to a complete stop at a stop sign. When the officer walks up to the vehicle, you hear him commenting on Cogswell's demeanor.

"You're shaking like crazy", the officer says to Cogswell.

In an interview with ABC15, Cogswell admitted he was shaking because he was extremely nervous. He had been pulled over and arrested for DUI by the same police officer, and he says he feels like he is being targeted because of his job in the medical marijuana industry.

Cogswell also admits he had consumed cannabis before the stop but said it was 14 hours before the traffic stop.

"I had an edible to help me fall asleep and I smoked a joint before I went to bed," said Cogswell.

Cogswell was also nervous because he was aware that even a trace amount of THC in his blood could mean another DUI charge. THC is the compound in cannabis that provides the 'high.'

"I had marijuana in my blood", said Cogswell, after getting his blood test results back from the police investigation weeks later.
Medical experts ABC15 spoke to said THC could build up in your system.

"If you are a regular user, someone who is using consistently, it is probably going to stay in your system a little bit longer," said Christina Orellana, a therapist at the Scottsdale Recovery Center.

But when it came to at what point it should constitute driving impaired, nobody seemed to have a solid answer.

"You have instances where it can stay in your blood for more than 30 days post-use," said personal injury attorney Marc Lamber with the Fennemore Craig law firm.

"What I've been telling people just based off of my experience is that they shouldn't drive within 12 hours of smoking," said criminal defense attorney Russ Richelsoph with the Davis Miles McGuire Gardner law firm.

ABC15 also took that question to a DUI officer, certified in drug recognition, and trained as an instructor to teach others how to become a drug recognition expert. George Chwe, with the Mesa Police Department, also oversees all DUI programs in the state through the Governor's Office of Highway Safety.

"So, if that person consumed marijuana within 24 hours, they can be impaired," said Officer Chwe.

He said the state has been tracking the numbers, and in 2020 almost 50% of all DUI citations were issued to drivers on drugs other than alcohol.

"As far as marijuana is concerned, about 68% of all the drug cases, [not just] DUI's that we deal with contain marijuana," he added.

With marijuana now legal for recreational use, Chwe said law enforcement agencies anticipate seeing those numbers increase.

Now more than three months since Arizona voters approved the legalization of cannabis for recreational use, the challenge facing law enforcement agencies and users remains that DUI laws have not been updated to define how high is too high. Unlike alcohol, where the legal limit is set at 0.08 blood alcohol level, there is no limit set for marijuana in Arizona or many other states that have legalized recreational pot.

"There is no set level of nanograms of THC that is deemed 'impaired' in the scientific community," said Chwe.

Colorado finally set a limit of 5 nanograms of THC per milliliter of blood after a fiery debate. That standard came three years after the state first legalized cannabis.

Experts say the lack of definition on what constitutes a level of THC to become impaired is due to the comparative lack of research on cannabis and its effect on the human body, especially when compared to alcohol. Those kinds of studies have begun, but are still in progress.

Law enforcement agencies also say the technology to measure THC is not as advanced as what is available to measure alcohol. Some states are using so-called 'marijuana breathalyzers,' but the accuracy of those devices is still in question. In Mesa, Chwe said officers use a 'Drager test' that screens for drugs present in a saliva sample, but it is used only for informational purposes and not for an arrest.

"That is still not something that they are allowing into court as of now," said Officer Chwe.

ABC15 reached out to multiple law enforcement agencies to find out how they plan to test impaired drivers for marijuana use right now. Mesa, to Phoenix, and the state Department of Public Safety, all pointed to standard field sobriety tests designed to measure for alcohol impairment as their go-to for now.

"A walk and turn, one-leg stand, a finger to nose test," said Officer Chwe of the various types of field sobriety tests already in use. Even though the tests were designed for alcohol impairment, Chwe explained that the purpose of the tests was to determine if a driver could multi-task by having them perform more than one thing at a time.

"They are divided attention tests, so we want to see what their concentration looks like because driving as you know is a divided attention task," said Officer Chwe.

But Adam Cogswell, the medical marijuana employee, said no matter how you fared in those tests if THC was found in your blood, you were doomed.

"You may look sober, you may act sober, you may be able to pass the field sobriety test but if they pull your blood and there is any sort of trace of marijuana in it, it is a DUI in the state," said Cogswell.

He said he planned to move out of Arizona as he could not risk getting a third DUI.

"It's three strikes and you're out. I can't do that to my family," he said.

He said he wants to leave with a warning for all cannabis users: the state may have given you permission to use the drug, but when it came to driving, the DUI laws were strict.

"I feel like you're a sitting duck. I was humiliated, I felt set up. I felt like my state gave me permission to use a product, at the same time by punishing me for using that product. The last thing I want to do is to have to go to prison for years over something the state has given me permission to use," said Cogswell.

Chwe said many police agencies are now training officers to specifically recognize the signs of marijuana impairment. Mesa also hoped to launch an educational campaign for the public, warning them of the dangers of driving while under the influence of marijuana.

Lamber, who had represented many family members of DUI crashes in court, said the message here was simple.

"Don't get behind the wheel if you've used marijuana. You can impact a life, forever," said Lamber.

But the million-dollar question remains. Does the presence of THC in your blood mean you are 'impaired' to the slightest degree? Cogswell said he feared this was a very subjective question, that would be defined by officers who pulled someone over for any traffic violation.