Marijuana Roadside Breathalyzer: Is It on the Way — and Will It Work?

In 2013, Colorado passed a THC driving bill, which established a cannabis intoxication level of 5 nanograms per milliliter of blood.

The standard was controversial from the jump, in part because THC tends to react very differently depending upon who consumes it — and the substance lingers in one's system for far longer than does alcohol.

Moreover, determining whether a driver has exceeded the THC limit can't be determined as quickly as is possible when it comes to booze. A blood test is required, making roadside analysis impossible.

But that could be changing.

California-based Hounds Lab maintains that it's developed a marijuana breathalyzer — a claim that's been greeted with varying degrees of skepticism.


The firm's website, which uses the phrase "Detect to Protect," doesn't feature any images of the device, which is still in development, but it contains lots of hype about how it will work.

"Using cutting edge science and technology, Hound Labs, Inc. can detect and measure THC in breath," an excerpt from the site's "Our Science" section reads. "Using only one or two breaths, the patent-pending science and technology detects THC and through an extraction process, measures THC to levels well below 500 picograms. The Company’s scientific breakthrough was specifically developed to be miniaturized and is currently being optimized for a handheld device at a price practical for use by law enforcement at the roadside.

"Prior to the invention of The Hound™ technology it generally took dozens of breaths to gather enough THC to accurately detect it," the text continues. "And no hand-held device has been able to measure the actual levels of THC, which is critical to developing standards for breath that ultimately correlate with impairment. Since measuring THC in breath was not possible before Hound Labs, Inc.'s scientific breakthrough, law enforcement and employers relied on saliva, urine and blood tests. The critical failure of these methods is that they do not distinguish recent use from THC used last week. Research indicates that people are most impaired only within a couple of hours after smoking marijuana, not days later."


According to his bio, Hound Labs founder Dr. Mike Lynn is "a practicing emergency medicine physician and teacher at a premier trauma center in Oakland," as well as "a clinical faculty member at the University of California San Francisco" — and he's been making the media rounds of late, as evidenced by a recent appearance on Fox Business shared below.

However, a just-published analysis by the National Journal suggests that coming up with a workable pot breathalyzer will be mighty difficult.

Among the experts consulted by the Journal is Carl Hart, a pro­fess­or of psy­cho­logy and psy­chi­atry at Columbia Uni­versity who calls the concept "a dumb idea."

Why? "The chem­istry of al­co­hol is such that there is es­sen­tially no blood-brain bar­ri­er for al­co­hol, so what is in your lungs or blood is the same amount, typ­ic­ally, as what’s in your brain,” he tells the publication. “With marijuana or any oth­er drug, we can’t do that. We have no idea what’s in the brain based on some meas­ure in your mouth or in your lungs."

Also dubious is Jason Thomas, who's described as a former Denver detention officer and Marshal's deputy; he's the principal of Avalon Realty Advisors, a team of "commercial real estate and business consultants who specialize in the Medical and Recreational Marijuana industries." His view? "If you were to take some­body that is a heavy can­nabis user, they’re cer­tainly go­ing to have a much high­er test res­ult than someone who oc­ca­sion­ally uses it.... How do you quanti­fy that?”

Breathlyzer testing is set to take place this year in Oak­land and Berke­ley, and Lynn hopes a version of the gizmo will be ready for law-enforcement use by the end of 2016.

But presumably only if it works. Here's the aforementioned Fox Business interview with Lynn.