It’s a problem that lots of states have struggled with in recent years as the nation has moved to marijuana legalization and pot usage has spiked.
How can police tell if someone is driving under the influence of cannabis?
Though possession of small amounts of marijuana is legal in Virginia, driving while intoxicated — including under the influence of pot — remains a serious crime in the Old Dominion, punishable by up to a year behind bars.
But the means to test drivers for impairment isn’t readily available for the state’s law enforcement agencies.
This month, the Virginia Crime Commission — an arm of the General Assembly tasked with studying issues of criminal law and making recommendations — discussed some potential steps police and sheriff’s offices can use to crack down on driving while high. The commission is expected to meet Dec. 5 to draft their proposals for the legislative session that begins in January.
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One thing under consideration at the commission’s Nov. 16 meeting: changing state law to allow roadside screening devices in which officers and deputies can have a driver swab his or her cheek in order to gather saliva to test for marijuana and other drugs.
For alcohol, Breathalyzer tests and blood draws can determine whether driver’s blood alcohol content is at or over the legal limit, 0.08, at the time it is taken. But there’s no similar accepted intoxication point for pot.
THC — the psychoactive chemical component of marijuana — typically remains active in the bloodstream for between four and six hours. But it’s nearly impossible to tell exactly within that time frame when the user consumed the drug.
That makes it difficult for police officers to know whether a driver was high at the time of a traffic stop — or, say, three hours earlier.
Virginia officials said the “oral fluid tests” under consideration to detect marijuana intoxication are similar to a “preliminary breath test” — a roadside test for alcohol. The test results, while not admissible in court, can help determine when the cannabis was consumed, and can be combined with other factors to get probable cause for extensive blood testing.
“You swab the inside of someone’s mouth, and you get a positive or negative and it just gives you some indicators,” Virginia Crime Commission Executive Director Kristen Howard told the Daily Press and Virginian-Pilot. “It’s designed to hone in on the recentness of use — how many hours ago you used this drug.”
Another possibility being discussed: training more police officers and sheriff’s deputies statewide to become “drug recognition experts.” Those are specialized officers who are called in to evaluate whether someone is high behind the wheel.
A Virginia State Police official, 1st Sgt. Dominic Sottile, told the commission the state and local agencies currently have 58 drug recognition experts. But he said he would like to have at least 100.
“He is who I’m calling when I don’t know what I’m seeing on the side of the road,” Sottile said. Sometimes officers might think they are dealing with an alcohol case, he said, but “30 minutes later a second drug might kick in.”
The Virginia General Assembly legalized marijuana in 2021. That meant people can use the drug in their private homes, and can grow up to four plants at home for their personal use. Using marijuana in public became a civil penalty punishable by a $25 fine.
But neither drivers nor passengers on Virginia’s roadways can legally use the drug in a car. And it remains a Class 1 misdemeanor — punishable by up to a year behind bars — to drive under the influence of pot.
Under Virginia law, it’s against the law to drive with a blood alcohol concentration of .08% or “while such person is under the influence of any narcotic drug.”
They also can’t drive under the influence of “any other self-administered intoxicant or drug of whatsoever nature, or any combination of such drugs, to a degree which impairs his ability to drive.”
There’s been a concern that driving while high will increase with marijuana legalization. Some of the more significant opposition to legalization in 2021 came from the American Automobile Association and other groups that voiced concern that the change would make roadways more dangerous.
A recent state survey by the Cannabis Control Authority indicates a lax attitude among many in Virginia, with a substantial number of respondents indicating that driving after using pot is OK.
For example, the survey found 11% of respondents said they’ve driven at least once a month after using marijuana. Moreover, nearly a third of respondents believe people “tend to drive slower and more cautiously and are safer drivers” after using pot.
Just 26% of respondents think it’s “extremely” dangerous to drive after smoking marijuana — compared to 49% of people who say the same for someone who’s had three alcoholic drinks in a two-hour period.
Dr. James Hutchings, the toxicology program manager for the Virginia Department of Forensic Science, had a different take, saying THC can significantly impair drivers.
“When you think about driving, you have to think about what are all the necessary requirements for safe driving,” he said. “You think about coordination, the effects on your muscles and nerves, being able to hold yourself up and steer, your reaction time — how fast are you able to respond to an outside stimulus.”
THC, he said, can also affect anticipation, judgment, attention, risk-taking, maintaining a safe distance “and your ability to stay on task as you’re driving along the long straight highway.”
But it’s been difficult for Virginia law enforcement to arrest people for driving while impaired on marijuana. Because of how long THC stays in the body — and because different people may be impacted differently — “there’s not a specific concentration that corresponds to, ‘This person is impaired,’” Hutchings said.
“The science doesn’t support setting a specific value,” he said. “To say that ‘This person at this number is definitively impaired,’ we would not be able to support that scientifically.”
Still, the Virginia Association of Commonwealth’s Attorneys is asking the legislature to come up with a certain blood level of active THC above which driving in Virginia would be illegal.
“The fact that marijuana is legal shouldn’t change someone’s ability to endanger other people on the road,” Deputy Williamsburg-James City County Commonwealth’s Attorney Cathy Black told the lawmakers. “So we would suggest erring on the side of caution.”
People shouldn’t be allowed on the road, Black asserted, if they have “active psychoactive drugs” in their system.
She suggested a legal threshold of .002 milligrams of THC per liter of blood. About 75% of the samples that police submit to the state lab in marijuana impairment cases result in concentrations at that level or higher, Hutchings said.
But Black’s suggestion got pushback from Sen. John Edwards, D-Roanoke, the Crime Commission’s chairman, who said a certain THC level in the blood is arbitrary because it cannot determine how a driver was actually influenced by the drug.
“If you’re in a wreck or something, maybe some judge could decide that,” Edwards said. “But I think you have to show that your driving has been impaired.”
Statistics cited at the Nov. 16 meeting show about a third of fatal car crashes in Virginia included an impaired driver. But there’s no good data provided in terms of how many DUIs stem from drug usage rather than alcohol.
Under current practice, the Department of Forensic Science doesn’t test for drugs unless someone has a blood alcohol content of less than .10. That should begin to change in early 2023, when the Department of Forensic Science will test all samples in impaired driver cases for drugs.