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Are Roadside Cannabis Breathalyzer Tests Around the Corner?

The trend toward marijuana legalization collides with the decades-old road safety push.

Photo Credit: Shutterstock.com/ zstock


Tens of millions of drivers face the prospect of a breathalyzer test for weed in the coming years in the U.S. as the trend toward medical marijuana legalization and outright adult-use legalization collides with another trend: the decades-old push to make the roads safer.

The much-feared breathalyzer for weed isn’t going to rely on breathing, however, it’s going to use spit. And when combined with unjust, new “zero tolerance” laws, futuristic roadside THC tests promise to pick up where the old fashioned drug war left off.

Road Carnage

Roughly 33,561 people died in traffic collisions in America in 2012, and doctors admitted about 2.3 million adults into emergency rooms for traffic-related accidents in 2009, the CDC reports.  Traffic collisions are the leading cause of death for U.S. teens, and this is after a decades-long campaign to bring the number of injuries and deaths down.

That campaign has been successful. Traffic fatalities are at historic lows, arguably through the use of tough seatbelt laws and drunk driving laws combined with checkpoints and saturation patrols around holidays.

Driving Under the Influence investigations begin with such checkpoints, or a roadside stop for an infraction of some kind. If an officer suspects DUI, he or she will administer a motor skills test, and in the case of alcohol, an alcohol detection screening commonly dubbed a ‘breathalyzer’.

The portable handheld device gives officers a basic idea of a person’s blood alcohol content and anything over .08 is a “per se” DUI, meaning it doesn’t matter if you don’t feel or act drunk, legally you are considered drunk. Failing a breathalyzer test will lead to your arrest and urine or blood testing back at the station, which is used in a defendant’s trial, notes California attorney Omar Figueroa.

For weed, things are different. In California, it’s illegal to drive high on any drug, but there is no “per se” limit set for weed. (Scientifically, the amount of marijuana compounds in a person’s system does not correlate to impairment.) So if an officer thinks you’re high, they can give you a skills test, but there’s no breathalyzer stage to back up what an officer suspects. Drivers suspected of a marijuana DUI have to be cuffed and taken in for a urine or blood draw, which takes time and money, so it’s often reserved for serious injury collisions.

But many think that’s about to change.

Sudden Gasps

In August, Baltimore research Sarah Himes published a study in the Journal of Breath Research that caught fire. She collected exhaled breath from 24 smokers and non-smokers using breath pads and tested them for THC, the main active ingredient in marijuana. Sure enough, she could tell who had just smoked a joint and who hadn’t.

“Breath may offer an alternative matrix for testing for recent driving under the influence of cannabis, but is limited to a short detection time (0.5-2 h),” the paper concludes.

Huffington Post, Mother Jones and others jumped on the story, despite that fact that the science behind testing breath for THC goes back to at least 1982. The method is also totally impractical in the field, where untrained officers need to rapidly assay the presence and concentration of pot in a driver’s system.

A company called SenseAbuse also made waves in 2013 after the press billed it as a breathalyzer for marijuana. Again, subjects had to exhale into a cartridge which had to be sent off to a lab for analysis. That can take weeks, so it’s not a real breathalyzer.

Some Cheek