Enter the marijuana breathalyzer

Officers from the Los Angeles Police Department conduct sobriety tests at a checkpoint in Hollywood over the Memorial Day weekend. 5/24/2014
Wikimedia Commons/Scott L.

One of law enforcement’s great frustrations with legal marijuana — and anti-legalizers’ perennial talking points — has been the absence of a reliable way of determining if someone has been driving while stoned.

A marijuana high (and therefore impairment) usually lasts two or three hours after a user smokes, and maybe a couple of hours longer if someone is using edibles.

The problem is that the traditional methods of testing for whether someone has been using marijuana — urine tests, hair tests and even blood tests — don’t account for how long THC has been in a drivers’ system (which can be for a month or more) and therefore don’t reveal if a driver was actually impaired when he or she was pulled over.

There is no marijuana breathalyzer that allows cops to administer the sort of instant roadside sobriety test typically used to measure impairment from alcohol.

That, however, may be about to change.

A couple of companies are developing breathalyzers for marijuana. One of them, Hound Labs, an Oakland, California-based start-up, has been field testing its device.

According to a list of answers to frequently asked questions posted on the company’s website, the Hound breathalyzer detects THC particles in a person’s breath in just minutes “and measures to very low levels — parts per trillion.”

“The reason this capability is so important is that THC stays in breath approximately two hours, which aligns with the actual window of impairment,” the company says.

The company also says its device can measure both smoked marijuana and edibles, a capability it calls “truly groundbreaking.”

“Up to now, we are aware of no instrument that could measure both types of use in breath,” it said.

What’s more, the device will be able to detect alcohol in addition to marijuana, which will make it easy for law enforcement to use.

Roadside sobriety testing is not the only market Hound Labs intends to pursue.

The company will also target employers wanting to use the device to measure whether workers are impaired on the job instead of whether employees may have smoked (legally) days or weeks earlier but are not impaired at work.

The company also intends to develop a consumer product that will let marijuana users measure their breath THC concentration.

“In stark contrast to alcohol,” the THC content of marijuana “is largely unregulated, so users generally cannot predict the amount of THC they have smoked,” the company says. “Imagine not knowing whether your 12-ounce drink is 4 percent alcohol (as in a beer) or 40 percent alcohol (as in a martini).

“We know now that it would be dangerous to consume an unknown amount of alcohol and simply guess whether you are too impaired to drive legally. Yet that is exactly what marijuana users must do because they can’t easily estimate their THC levels and are unable to accurately predict if they’re impaired,” the company says.

The THC content of most pot sold in Colorado is printed on the label, but the measure is not as accurate as the measure of alcohol content in booze; frequently the THC level is given as a spread — from 7 to 14 percent, for instance. It’s unlikely that THC content of smokable pot can be given more precisely any time soon, since it can vary dramatically from plant to plant and even bud to bud.

Hound Labs says its detection technology is proprietary and the website doesn’t contain a description of how it works.

However, another company developing a marijuana breathalyzer is somewhat more forthcoming. Cannabix Technologies of Vancouver, British Columbia, says it is developing a device “based upon high-field ion mobility and mass spectrometry.” The company has an “exclusive worldwide [patent] in the areas of breath analysis of controlled substances,” it says.

Just how reliable either company’s devices turn out remains to be seen. Devices that measure samples in parts-per-trillion in a roadside setting will have to prove they can be consistently accurate in difficult conditions, which may not be trivial.

Still, if an accurate way of measuring drivers’ pot impairment in near-real-time becomes available, it will deprive marijuana prohibitionists of one of their few remaining arguments against legalization. As they say at Anheuser-Busch, Dilly, Dilly. 

  • jontomas

    There’s something missing from this article………….

    It’s any indication or proof that marijuana consumption causes significant impairment or accidents. — That’s because it doesn’t.

    Marijuana is not alcohol. The preponderance of the research shows marijuana consumption is NOT a significant cause of auto accidents. In 2015, the Drug and Alcohol Crash Risk report, produced by the U.S. Department of Transportation’s National Highway Traffic Safety Administration, found that while drunken driving dramatically increased the risk of getting into an accident, there was no evidence that using marijuana heightened that risk.

    In fact, after adjusting for age, gender, race and alcohol use, the report found that drivers who had recently consumed marijuana were no more likely to crash than drivers who were not intoxicated at all.

    It’s a shame that because of hysterical propaganda and un-verified ASSUMPTIONS, people will be punished who are not creating any danger on the roads.

    Here’s hoping we wake up from this bit of Reefer Madness soon!

  • Michael Milburn

    The specter of carnage on the road following cannabis legalization is propaganda from prohibitionists. Cannabis is not being invented, just legalized–people have been driving stoned for decades. No one should drive impaired, but actual impairment should be measured, and the level of impairment from cannabis that is criminalized should be the same as the level of impairment for the .08 blood alcohol level. How to measure impairment? Read on!

    The breathalizers mentioned don’t measure impairment from edibles, and I have heard there is not enough THC in breath for these technologies to work. Instead, I have developed a new public health app that measures actual impairment–it is called DRUID (an acronym for “DRiving Under the Influence of Drugs”) available now in the App Store and in Google Play. DRUID measures reaction time, decision making, hand-eye coordination, time estimation and balance, and then statistically integrates hundreds of data points into an overall impairment score. DRUID takes just 2 minutes.

    Our website is http://www.druidapp.com

    DRUID allows cannabis users (or others who drink alcohol, use prescription drugs, etc.) to self-assess their own level of impairment and (hopefully) decide against driving if they are impaired. Prior to DRUID, there was no way for an individual to accurately assess their own level of impairment. DRUID also demonstrates that it is feasible to measure impairment reliably by the roadside, not just exposure to a drug. It could also be a way for cannabis users who have developed tolerance to show they are unimpaired.

    DRUID was featured on NPR’s All Things Considered: http://www.npr.org/2017/01/25/511595978/can-sobriety-tests-weed-out-drivers-whove-smoked-too-much-weed

    Also on television: http://sacramento.cbslocal.com/2017/02/28/science-lags-behind-marijuana-impairment-testing/

    And this past week on Spokane Public Radio: http://nwpr.org/post/progress-made-marijuana-intoxication-measurement-tool-0

    After obtaining my Ph.D. at Harvard, I have been a professor of psychology at UMass/Boston for the past 40 years, specializing in research methods, measurement and statistics.

    Michael Milburn, Professor
    Department of Psychology

    • jontomas

      So what tests have you done to show that “impairment” from marijuana as measured by DRUID equals actual impairment and accidents caused on the highway? – As the NHTSA research shows, there is no significant impairment or accidents from marijuana consumption.

      • Michael Milburn

        My argument is, as cannabis-impaired driving is criminalized, that actual impairment should be measured. And, the criminalized level of cannabis-impairment should be the same as the impairment resulting from a BAC=.08 level for alcohol. My suspicion is, that the impairment level from cannabis that most are comfortable at is much lower than the .08 level for alcohol. But we are conducting studies now to test that.

        • jontomas

          It seems you are still starting with the ASSUMPTION that marijuana causes significant impairment and accidents. – The preponderance of the research shows it does not. I fear your desire for sales may also taint your “conclusions.”

          Have you seen this excellent piece of video journalism? They actually tested drivers on a track at various levels of consumption. – Every driver tested did not want to continue driving after reaching a certain level of consumption. Only after being urged and told it would be safe on the track to do so, did they continue. — This holds true in normal driving also. – Judgement is not affected by marijuana as it is by alcohol. People choose NOT to drive if they have consumed too much.


          • Michael Milburn

            NORML of California is promoting DRUID on their website and is encouraging cannabis users to download it. Are you trashing them, too?

  • Klaus

    Keep the loonies on the path, keep the loonies on the grass !!!!!!

    • jontomas

      Thanks for showing the level of reason (sub-zero) of prohibitionists.