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Volunteers smoke, drive for science in Bay Area [News Brief]

August 17, 2017
Hound Labs track test
courtesy of Hound Labs
Hound Labs track test
SOURCE: courtesy of Hound Labs

As more states move to legalize recreational cannabis, driving under the influence of pot remains illegal. For law enforcement, this is where the rubber hits the road.

In a high-speed driving test conducted in June, researchers from a Bay Area company working on a pot breathalyzer, Hound Labs, found that drivers made numerous “potentially fatal errors” 30-45 minutes after smoking cannabis, including those with extremely low levels of THC in their breath.

Hound Labs claims it’s the first time anyone has measured driving performance -- judgment, reaction time, decision-making etc. -- in conjunction with THC breathalyzer measurements. Correlating the presence of THC with impairment has been notoriously tricky, and is seen as a major step toward a marijuana DUI standard similar to alcohol.

To develop the driving tests, Hound Labs worked with scientists from Triple Ring Technologies, a research and development firm based out of Newark, California, and Johannes van Overbeek, a professional race car driver.

The team developed a 1.5 mile driving course, containing construction zones, debris, standard road signs, and unexpected obstacles (including a bicycle on the road) to test driver ability both sober and stoned.

Three drivers participated in the test. As they completed the course, van Overbeek sat in the passenger seat.

“When the drivers were sober, they made no mistakes, but each driver made a series of errors when stoned – hitting cones, crashing into larger obstacles, and unfortunately colliding with a bike that was on the shoulder of the road,” said van Overbeek.

Hound Labs Track Test 170720 from Susan Allan on Vimeo.

In a video provided by the lab, all three drivers, while stoned, are shown hitting the “cyclist” on the road. And, according to Mike Lynn, CEO and Co-Founder of Hound Labs, two out of three drivers weren’t aware they hit the bike.

The new data contradicts other studies showing there is no risk of driving under the influence of marijuana in and of itself.

In a 2016 study including 9,000 drivers conducted by the National Highway Traffic Safety Administration, researchers found that -- after controlling for common confounding factors like alcohol use, age, gender, ethnicity, and day or nighttime driving -- having marijuana in your system doesn’t “significantly contribute” to crash risk. By contrast, those with breath alcohol concentrations of .05 and .08, however, were 2.07 and 3.93 times more likely to crash than sober drivers, respectively.

Hound Labs
The Hound Labs marijuana breathalyzer. 

Other data points also undermine the case for increased stoned driving interdiction efforts. Two studies have shown vehicle fatality rates dropping after medical cannabis became legal.

Additionally, the number of drivers issued citations for stoned driving in Colorado has gone down, by 33 percent, in the first quarter of 2017 compared to the same time period of the prior year.

If THC does impair driving at any level -- where that level lies is still unclear, and sorting out varying tolerance levels amongst cannabis users is a major hurdle makers of cannabis breathalyzers will have to face.

The company plans to begin manufacturing the Hound marijuana breathalyzer at the end of 2017.