This article by Dr. Lloyd Covens originally appeared in the West420 News Weekly newsletter.

Canada and California officials have made it clear: on the way to legalization, they both want reliable, repeatable tools for police to use in detecting cannabis impairment in drivers.

While a blood-level standard of 5 nanograms (ng/ml in whole blood) seems to be an easy baseline for law enforcement, much more reliable measurements are being advanced by saliva swabs, training on impaired driver behavior, and even a high-technology approach able to find tiny amounts of THC in air vapor.

In Canada, the Justice Minister Jody Wilson-Raybould introduced a bill giving cops the ability to collect a saliva (oral-fluid) sample after observing red eyes or smelling pot, or otherwise observing impaired driving.

A $1.6 million TV campaign will be targeted to young Canadians (age 16 to 24) telling them “consuming marijuana doubles your chance of a car accident,” and reminding the young drivers that cannabis often gives the user a false sense of safe awareness behind the wheel.

A separate EKOS Canadian report earlier this year reported 25% of drivers admitted being under an MJ influence, with 42% having smoked before getting behind the wheel by recent use. The poll also reported 42% of passengers in the 19 to 24 age bracket said their driver had used cannabis earlier that day.

In San Diego, local cops have been using the Drager 5000 portable unit since March. San Diego police will first observe a driver to make an initial determination about possible impairment, after which the motorist may then be asked to run a mouth swab for as long as four minutes. Results from the portable Drager 5000 is available in under 10 minutes.

As with a Canadian plan to set an impaired standard tied to saliva tests, the California field test initially may only seek to determine that the driver had smoked cannabis within the two hours preceding the test.

With access slated to start in mid-2018, the Canadians are hyper-sensitive about teen access to newly recreational availability. The current RMJ draft in Canada would make a possible MJ impaired fatality punishable by a wide range from a $1000 fine up to life imprisonment, depending on the circumstances.

“Prohibitionists are happy to spread dis-information and manufacture hysteria,” claimed long-time industry expert Michael Elliott. He notes that thus far setting an arbitrary limited of 5 ng ignores the presence of THC weeks and days after consumption. As such, Colorado allows “permissible inference” (a defense which state’s why a person, such as an MMJ, patient might consume more and still be safe), versus a Washington state model which holds a “zero tolerance law” — if your THC test passes 5 nanograms, you automatically lose your license.

Last month the Highway Loss Data Institute used a small data set to conclude that collision claims have gone up in newly legal MJ states. Without backing its estimates to specific crash data, HLDI claimed accidents in Colorado were up (in 2015) 16%, in Washington up 6.2%, and Oregon collisions up 4.5%. Elliott notes that the industry has to educate law enforcement (and the courts) on why some MMJ patients (medicating with daily doses of 300-400 mg per day) actually are not impaired at all, whereas a mid-western tourist might be impaired from a 10mg cookie. “We do need to take this seriously as an industry,” says Elliot.

Accurate vapor pressure measurements for THC will help ensure marijuana breathalyzers are calibrated to a consistent standard. Technology from the area of very sensitive detection of vapor (ie., airports smelling tiny amounts of explosives) is also being studied for detection of THC. The researchers used a technology called PLOT-cryo (porous layer open tubular cryogenic adsorption) which uses frozen gas to identify chemicals based on the make up of vapors released into nearby air. It has since been used to sniff fire debris for evidence of arson and to find clandestine graves by following the faintest scent of decomposition.

PLOT-cryo is so sensitive it can analyze even the relatively few molecules of THC that escape as vapor. In experiments they swept a harmless gas across a sample to capture them, then chilled the gas to collect them. By measuring their mass in a known volume and temperature, the researchers calculated the vapor pressure. Co-researcher of the study, Dr Tom Bruno said: “PLOT-cryo is an extremely sensitive technique for capturing and analyzing things in the vapor phase. It was a natural candidate for this type of problem.” Bruno added, “Fundamental measurements are the basis of standardization. We are laying the foundation for the reliable systems of the future.”

The study published in Forensic Chemistry said the next step is to understand how breath levels of THC correlate with blood levels, and determine the amount of THC in the blood that indicates a person is too impaired to drive.