There’s no Breathalyzer for pot. Police in Maryland struggle with determining impairment

Changes to Maryland’s marijuana laws continue to raise questions — and challenges — for police trying to enforce laws against driving under the influence.

During a meeting with members of the Montgomery County Council’s Public Safety Committee, Montgomery County police officer Jayme Derbyshire told council members, “as far as admissibility goes, really, what we have are validated tests for alcohol impairment, and that’s essentially” it.

Derbyshire was asked about what kind of tests for impairment would stand up in court.

There’s no single test for impairment from cannabis use like the Breathalyzer, which is used to determine alcohol intoxication in Maryland.

Some states, such as Alabama, allow results from “oral fluid” drug tests, which use saliva samples, to be used to show impairment from cannabis. While the Montgomery County Police Department has bought some of those test kits, Derbyshire told the panel proving impairment “would still be very dependent on an officer’s observations,” but she said it would “at least help us with regards to the presence of that particular drug.”

There are also questions about just how high is too high to constitute being impaired.

Derbyshire said police in Montgomery County have made used of a “green lab,” where volunteers come in and ingest cannabis under controlled conditions at the department’s training academy.

She said, in national research, tests do show that “cannabis is impairing to the point where people can’t operate a motor vehicle safely,” but she said the maximum percentage of THC concentration used in those tests is 14%. Subjects in the Montgomery County police green labs are told to bring the cannabis products they would typically consume.

“Their average is about 68% THC content, so a lot higher,” she said.

One of the advantages to conducting the training, said Derbyshire, is that it’s “very helpful” as a community engagement tool.

“The cannabis community is not one that we often interact with on positive terms, and this has really kind of done wonders to bring us together and foster understanding” on why impaired driving while under the influence of cannabis “is such a danger,” she said.

The Marijuana Policy Project, an organization committed to legalizing cannabis, has written on its website that it supports “impairment-based drugged driving laws,” but said, “as recent peer-reviewed scientific studies demonstrate, there is no substance to the argument that removing penalties for adults who responsibly consume marijuana makes our roads less safe.”

Kate Ryan

As a member of the award-winning WTOP News, Kate is focused on state and local government. Her focus has always been on how decisions made in a council chamber or state house affect your house. She's also covered breaking news, education and more.

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