Impact of legal marijuana on driving in Maryland is tough to gauge, and enforcing impaired driving laws is complicated

BALTIMORE -- At the end of June, as many Marylanders eagerly anticipated buying recreational marijuana legally for the first time, Sgt. Thomas Morehouse was worried about the safety of Baltimore County’s roads.

Morehouse, a certified drug recognition expert for the Baltimore County Police Department, was concerned about residents lighting up and then getting behind the wheel after July 1.

“Every state that has legalized recreational cannabis has seen increases in fatal crashes, injury crashes, property damage crashes and other irresponsible driving because of impairment by cannabis, so I don’t expect Maryland to be any different,” Morehouse said in a June interview with The Baltimore Sun.

Several factors make it hard to gauge the impact of recreational weed on driving in Maryland so far.

A look at statewide crash data showed a small uptick in traffic crashes in July compared to previous years, according to the Maryland State Police. But enforcing traffic laws when it comes to cannabis consumption is complicated — there is no widely used breath test to detect it and experts say proving impairment from a blood test can be challenging.

Further, the number of arrests for driving while impaired with alcohol in July dwarfed the number of arrests for driving high in Baltimore City and the counties of Anne Arundel, Baltimore, Carroll and Harford, with only a handful of traffic arrests related to cannabis, according to law enforcement agency data.

“Just as people shouldn’t drink and drive, cannabis is no different: It is a psychoactive substance, and you shouldn’t get behind the wheel and potentially put yourself and others in danger,” said Chad Johnson, an assistant professor in pharmaceutical sciences at the University of Maryland, Baltimore in a July interview. “But ... identifying it, I think, will be a challenge.”

The Marijuana Policy Project, a marijuana advocacy group, says on its website there is no evidence that statewide legalization increases traffic fatalities and cites a study showing similar crash rates in states with and without legalization.

Preliminary state crash data from the Maryland State Police shows there were 88 more vehicle crashes during July than in the same month last year, a 1% increase. But there were fewer crashes this July than in the same month in 2019, 2020 and 2021.

In July, law enforcement agencies in Maryland made 806 DUI arrests and 338 arrests for driving under the influence of drugs, as captured through E-Tix software, slightly fewer in each category than in July 2022, according to state police data. The agency said it could not provide data on cannabis arrests specifically.

Neither Baltimore Police nor the Carroll County Sheriff’s Office arrested anyone for driving while impaired by cannabis in July, but six people in each jurisdiction were arrested for driving while under the influence of alcohol.

Baltimore County Police made 74 total DUI arrests in July, 67 of them for alcohol and four involving cannabis. Anne Arundel made a total of 47 DUI arrests, including 20 for driving while suspected of being impaired by drugs, although a police spokesperson said the department could not provide the number of specific cannabis arrests. In Harford County, there were 13 DUI arrests and two arrests for driving while impaired by cannabis.

State law does not allow cannabis users to smoke in vehicles or public places, but under new state law, police cannot use the odor of marijuana as the sole reason to make a stop or to search a vehicle.

Harford County Sheriff Jeffrey Gahler said officers who suspect someone of driving under the influence of alcohol can do a series of field sobriety tests and have them blow into a toximeter.

“You have a scientific instrument that tells you if you’re at a level of impairment or not,” he said. “No such instrument exists for cannabis, so you have to have the resources of a drug recognition expert.”

Drug recognition experts are officers or troopers who undergo specific training on recognizing the effects of various drugs on drivers. There are about 190 of them across Maryland, state police spokesperson Elena Russo said in June. Maryland’s first nine drug recognition experts were trained and certified in 1990. While a patrol officer or trooper can perform basic field sobriety tests, a drug recognition expert needs to get involved before police can request a blood sample.

“They’re specially trained to do a very systematic and standardized evaluation: a bunch of observations, divided attention tests, some medical things like pulse and blood pressure measurements, we’ll do some eye exams,” said Morehouse, one of 29 drug recognition experts in Baltimore County.

If an officer suspects drug impairment after such an evaluation, they can request that drivers submit to a blood test. Police can’t compel a driver to take a blood test unless a vehicle crash results in death or life-threatening injury to another person, but refusing the test comes with penalties like a suspended license.

In 2012, Carroll County Judge Michael M. Galloway granted a motion to exclude drug recognition expert testimony from 27 cases after hearing testimony from medical experts on a national certification program. Galloway wrote in his ruling that the program “is not generally accepted as valid and reliable in the relevant scientific community,” and that the protocol “failed to produce an accurate and reliable determination of whether a suspect is impaired by drugs.”

Owings Mills defense attorney Leonard Shapiro, who specializes in DUI/DWI cases, said he has never tried a case in which a Maryland judge allowed a drug recognition expert to express an opinion as an expert in court.

Even with a blood sample, measuring marijuana intoxication is “murky,” said Johnson, who is also the co-director of the University of Maryland’s graduate program in medical cannabis science and therapeutics.

“Right now, there’s not a very unified approach for how to do this and do this fairly,” Johnson said.

Blood testing, the best biological method for detecting marijuana intoxication, can measure levels of THC, the psychoactive component in marijuana, for about five hours after someone inhales marijuana or 22 hours after taking it orally, Johnson said. Blood tests also identify liver products called metabolites, which persist in the body for longer.

“The cannabis plant affects different people in different ways: Your sex, age, body weight and tolerance to cannabis play a big role,” Johnson said. “If we’re going to enforce this fairly, they need to establish an intoxication level.”

Colorado has set a limit of five nanograms of THC per milliliter of blood, which allows for a “permissible inference” that a driver is impaired but does not require a court to find them guilty, unlike a 0.08% blood alcohol level.

Some have pointed out that Marylanders participating in the illicit or medicinal markets have consumed marijuana and tried to drive long before July 1.

“The issue of dealing with impairment isn’t new for law enforcement; the concern is one of magnitude,” said Mat Swinburne, associate director for the Network of Public Health Law’s Eastern Region, housed at the University of Maryland Francis King Carey School of Law, in a June interview.

Marijuana legalization was praised as a victory for racial equity, but enforcement of possession and driving laws still leave open the opportunity for discriminatory policing.

“Like every state,” Swinburne said, “Maryland has issues with the inequitable enforcement of law against Black or African-American drivers.”

The Baltimore Sun reported in 2016 that statewide traffic data showed police stopped and searched black motorists in Maryland at higher rates than white drivers.

An American Civil Liberties Union report on data collected from 50 states between 2010 and 2018 found Black people were more likely to be arrested than white people for marijuana possession, even in states that had legalized marijuana. During 2020, the first year marijuana was legalized in Chicago, Chicago Police arrested three times the number of African-Americans for marijuana-related offenses than all other ethnicities combined, the Chicago Tribune reported.

“It’s a good policy from a racial justice standpoint, but there’s still the challenge of enforcement, and you can still have inequitable enforcement of a just policy,” Swinburne said. “These struggles that we see in other states, Maryland is probably going to have to deal with those same struggles because we have the same built-in problems with our system.”

________