Does smoking pot or munching dope goodies impair driving? How much THC in your system means you’re too stoned to take the wheel? Never mind what your aunt or your next door neighbor says, scientists and law enforcement themselves don’t agree on whether or how much marijuana makes you a menace on the road, according to NPR.
While experts argue about drivers and weed, California-based Hound Labs developed a breathalyzer kit the company claims can detect and report THC or alcohol in a breath sample in about four minutes.
The Hound kit consists of a handheld device, a laptop-sized analysis unit, and consumable cartridges.Each cartridge has a blowing tube on one end to collect samples.
Stick a Hound cartridge in the handheld unit and blow on the tube for 30 seconds. Remove the cartridge and insert it into the larger unit called a breath processor. You’ll get the breath test results in under four minutes, Hound Labs CEO Mike Lynn told NPR.
Lynn, an emergency room trauma physician and SWAT team reserve officer, claims the Hound breathalyzer can sniff out marijuana use in the past two hours. Lynn told NPR two hours is key, for that’s the time range when impairment from smoking marijuana is greatest.
“When you find THC in breath, you can be pretty darn sure that somebody smoked pot in the last couple of hours,” Lynn says. “And we don’t want to have people driving during that time period or, frankly, at a work site in a construction zone.”
The Hound breathalyzer doesn’t report THC consumption levels, just its presence. Measuring THC is much tricker than alcohol, Lynn told NPR. Alcohol is measured in parts per thousand, but because THC is about a billion times less concentrated than alcohol, the Hound has to measure the psychoactive marijuana component in parts per trillion.
Even the feds aren’t sure if inhaling or ingesting THC before driving is dangerous. The National Highway Transportation Safety Administration(NHTSA)’s Crash Risk Study was inconclusive about whether marijuana impairment “contributes to the occurrence of vehicle crashes.”
The NHTSA’s study found that marijuana users were more likely to be in vehicle crashes than non-users, but the causal relationship isn’t clear since young men, already the top crash risk demographic, also have the highest weed use.
Most law enforcement experts, scientists, physicians, and insurance companies believe marijuana has a negative effect on driving performance, even if they haven’t yet found common ground on precise numbers.
While waiting for definitive THC level studies, some police departments are going to test Hound Labs’ breathalyzer later this year, Lynn told NPR.
“They’re interested in it providing objective data for them at the roadside,” says Lynn. “That’s really the key, objective data at the roadside — just like we have for alcohol.”