For years, law enforcement in states that, like California, have legalized cannabis for recreational and medical use have sought the equivalent of a DUI breath test device, but for marijuana. Entrepreneurs across the country have tried to strike it rich by inventing the first “marijuana breathalyzer” to accurately detect if a driver is impaired so they can be arrested for drugged driving.
So far, nothing like this has hit the market yet. And a scientific study from Australia suggests that a cannabis breath test machine might not even be possible.
‘Poor indicators’ to tell if someone is high
The study came from the University of Sydney. Researchers there say that measuring THC levels in the blood and breath the way an alcohol breath test device does is not an effective way of telling if someone is impaired. They are “relatively poor or inconsistent indicators of cannabis-induced impairment,” the study’s authors said.
One factor is that THC lasts in the bloodstream for much longer than it is having an effect on the person’s brain. A cannabis breath test device would indicate a certain level of THC in your system and give the officer justification to arrest you even though you last got high days or even weeks ago.
Can a San Diego officer know for sure?
For now at least, this leaves the police with other tests for impairment: whether the driver’s eyes are red, whether they smell of marijuana smoke, if their reaction times seem delayed. Such tests can be subjective and, at times, abused by the authorities.
Then it might become your word against the arresting officer’s at trial. As lawmakers and police struggle with finding a fair an objective way to measure someone for THC impairment, such dubious arrests could become common.