Marijuana breathalyzers have long been in development, producing no fruitful results. A new study shows a different path.
A new meta-study, led by researchers from the University of Sydney’s Lambert Initiative, has concluded blood or saliva THC concentrations are not effective ways to measure cannabis-induced driving impairment.
A new study led by researchers from Massachusetts General Hospital has identified a pattern of brain activity that seems to correlate with impairment from cannabis intoxication. The researchers suggest this novel brain-based biomarker could be a way to accurately measure THC impairment.
As more and more states legalize marijuana, scientists and entrepreneurs are rushing to devise a Breathalyzer for pot — something more objective than officers’ observations of people as they drive, and then as they attempt the walk-turn and the one-leg stand.
Can a breath test smoke out stoned drivers?
As more US states legalise marijuana use, the race is on to find a drug version of the roadside breathalyser
Unless there’s a scientific breakthrough to find a biometric that indicates intoxication that’s currently unknown, marijuana breathalyzers may never work.
The test could help reduce the number of intoxicated drivers on the road—or it could turn up too many false positives to be useful.
The Hound does not measure how stoned a person is. The existence of THC in the breath is considered proof enough that the person is stoned at the time of testing, according to Hound Labs.
Experts agree that marijuana impairs drivers, though not as much as alcohol does. But what concentration of THC makes a driver legally impaired? That’s a question still very much open for debate,
Some researchers say that limited resources are better applied to continuing to reduce drunken driving. Stoned driving, they say, is simply less dangerous.
Still, it is clear that marijuana use causes deficits that affect driving ability, Dr. Huestis said.
Breathalyzers for alcohol work on principles that don’t necessarily work for pot. And they’ve been extensively researched, which is difficult to do with federal controls on marijuana.
“There is no concentration of the drug that allows us to reliably predict that someone is impaired behind the wheel in the way that we can with alcohol,” said Jake Nelson, AAA’s director of traffic safety advocacy and research.
However, unlike alcohol where a driver is considered impaired at a certain level (.08) in Pennsylvania, there is no level set yet in the state in which a driver is considered impaired on marijuana. Pitt researchers said, many more studies need to be done to reach a conclusion on impairment when it comes to THC, the component in marijuana that gives a high.
Whereas urine tests detect the presence of marijuana up to a month after impairment subsides, and blood tests up to three weeks, breath tests have the shortest detection window of up to just two or three hours after smoking. It’s an important distinction for law enforcement, who could in theory use a positive result as evidence of driving under the influence.
But without a comprehensive understanding of the correlation between that amount and the driver's level of impairment, the device may not be particularly useful to police.
On top of that hurdle, there's the legal question of what level is safe for driving, which may be hard to answer. It took American courts several decades to settle on today's blood alcohol concentration limit of 0.08%.
As legal weed becomes a reality, researchers, startups, and law enforcement are racing to figure out how to test for THC intoxication.
Barring confession, there’s no way to tell if a driver is high.
So what’s a responsible stoner to do about the looming threat of an accurate field test for stoned driving? Go with it. Make that tiny sacrifice and stop being stoned while driving, and at the same time push for a field test that's even more accurate...
The search for a reliable method of determining levels of cannabis impairment continues as another pathway is closed off. Researchers say that saliva tests are poor indicators of impairment—meaning THC breathalyzers might be as ineffective as traditional THC tests at indicating if a driver is impaired.
Cannabix is developing breath testing technologies that can be used at the point of care to detect recent use of marijuana. Cannabix is developing its technology to help employers, law enforcement, government and the public, when marijuana is becoming legal for recreational and medicinal use in many jurisdictions globally.
The key to a fairer test is the ability to measure very recent marijuana use within several hours of smoking – a time frame that aligns with the window of peak impairment. That’s why the HOUND® MARIJUANA BREATHALYZER is a fairer test – it only measures very recent cannabis use.