How Police Officers Can Tell if You’re Driving High

Photo illustration of a girl smoking marijuana by @ashton via Flickr Commons

With the mainstreaming of marijuana since its legalization in 2016, law enforcement faces a quandary: how will police officers determine if someone is driving high?

Since January 1, 2018, adults ages 21 and over are able to buy marijuana for recreational use from licensed dispensaries – and much of what is for sale is easily consumed orally, leaving no tell-tale “pot smell.” On the same day, a new law went into effect that prevents smoking or ingesting marijuana while driving or being a passenger in a car – so how will police tell that drivers are high?

Since there is no legal threshold to mark marijuana impairment in California, officers are being trained to be drug recognition experts and conduct field sobriety tests, according to The Press Enterprise.

With pot-related DUI’s expected to rise in California, Investigator Weston Hadley of the Santa Ana Police Department Collision Investigation Unit said the assessment of an impaired driver typically begins with a traffic stop.

Hadley said that high drivers usually commit a traffic violation, which leads to officer contact. During the interaction, officers may notice symptoms of impairment, such as the distinct odor of marijuana. Officers will then question the driver, looking for signs of mental impairment or physical symptoms, according to Weston.

“Officers look for two distinct clues, first the reddening of the conjunctiva of the eye and second, they may look for the lack of ability to converge the eyes,” Hadley said.

If the officers detect signs of mental impairment, and objective signs of use, they will continue the investigation and initiate a formal DUI investigation; the officer will have the driver perform a series of balance and coordination tests that are used to detect impairment of the psychomotor skills, according to Hadley.

“The impairment of psychomotor skills provides the officers with visible evidence that the drug is affecting their nervous system,” Hadley said.

Based upon the totality of their observations, the officer will have to determine if they have probable cause to make an arrest, Hadley said.

When asked what technology officers have to detect marijuana intoxication, Hadley said
they have to rely on the quantitative testing of the arrestees blood which is analyzed by the Orange County Crime Lab.

“There are various companies beta-testing devices that provide qualitative drug results,” Hadley said. “They have not gained widespread use and acceptance.”

Photo of a a pipe with weed inside by @Mark via Flickr Commons.

Hadley said he has obtained multiple warrants to compel blood tests.

“My best estimate is 10-20% of arrests I have made require a warrant (since the McNeely Decision),” Hadley said.

While some users such as X claim they “drive better” high, recent studies have revealed drivers with THC in their blood were twice as likely to be involved in a fatal crash, according to The National Center for Biotechnology Information. Another study also revealed that those with high levels of THC in their system who were involved in car crashes are three to seven times more likely to be responsible for the incident than those who were not driving under the influence, according to National Institute on Drug abuse.

According to Doctor Richard Han, a board certified pediatrician who works at a free standing outpatient center in Phoenix, if someone drives high they may not notice details as well as they normally would.

“Being high, like under the influence of alcohol, or any other drug for that matter, can decrease reaction time, awareness and impair judgement,” Han said. “You may not see objects, notice pedestrians or gauge distances well, or judge speed and ability to change lanes, merge into traffic, etcetera.”

Someone’s degree of impairment also depends on how much they consume, Han said.

“Just like with medications, there will be a dose dependent relationship,” Han said. “For example, if one took just a few puffs, the high might only be enough to impair judgment a little, whereas if one smoked two joints, they might be barely awake.”

Photo illustration of medical marijuana cereal edibles by @Mark via Flickr Commons.

The level of driving impairment also depends on what you smoke, Han said.

“If you smoked something that was not just marijuana but say also laced with PCP (Phencyclidine– a drug used for mind altering effects), that would most certainly affect perception and distort vision, or even induce hallucinations,” Han said.

With the many different forms to smoke and consume cannabis, the only difference between smoking a joint versus eating an edible in terms of marijuana would be amount consumed and timing of effect, Han said.

“Inhaling a joint will cause a faster onset of effect and people tend to stop using it sooner since they feel it,” Han said. “Versus eating something and waiting for the delayed effect, which then sometimes causes people to eat more and more, and then get hit harder. The edible would probably affect a longer drive in terms of distance and timing since it would take longer to kick in and last longer as well.”

Interviews with Chapman students – all of whom insisted on anonymity – revealed that most have driven high at least once in their life or have gotten into a car with someone who was driving high.

A sophomore health science major said she has never driven high but has gotten into the car with someone who was driving under the influence.

“I’ve gotten in the car with someone who was driving high probably ten times, she was a very close friend who liked to smoke weed,” said the anonymous student. “I felt somewhat uncomfortable but we were so close I felt like I had to be comfortable with it since she said she drove high all the time.”

A freshman business major said she has driven high at least five times in her life and smokes daily.

“Sometimes I drive high because if I Uber my parents would question why I Ubered,” said the business major who was also disinclined to pay for a car service when she had her own wheels. She believed herself to be “a better driver when high because I know I have to be more alert while driving so I feel like I’m more aware of my surroundings.”

Yet, she concedes ingesting marijuana messes with her memory.

“One time I drove to In-N-Out (Burger) and I didn’t even remember driving there. The only way I remembered was seeing a video later that day on my phone that my friend took who was in the car with me,” said the anonymous student.

Some students such as freshman English major with an emphasis in creative writing realize the dangers of driving under the influence and has neither driven high or been a passenger in a car while someone was driving high.

“My sister got in a really bad car accident and was hit by a drunk driver,” said the anonymous student. “The doctors said they were surprised she survived, so ever since then I’ve been a little more cautious because I couldn’t imagine getting in the car and doing something like that to someone else.”

A sophomore environmental science major said she has gotten in the car while someone was driving under the influence.

“I have definitely gotten in the car when someone was driving high,” said the anonymous student. “I do this a couple times a year but I try to avoid it. Sometimes my friends and I are still kinda high but we all want to get food so we just decide to get in the car and go,” said the anonymous student.”

The anonymous student said she has driven high twice in her life but will no longer drive under the influence due to the risk of receiving a DUI.

“Many of my friends have gotten DUIs while driving high so I definitely won’t drive high again,” said the anonymous student.

Katie Whitman

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