TRUCE doesn't support impaired driving. Impaired by any driver act. Being able to pilot thousands of pounds of vehicle around at speeds able to do great harm to the driver and others if not done carefully and with full alertness is a privilege, not a inborn right in a sound society.
Equally, however, we know many patients and personal users around the country are being convicted of DWI charges for cannabis use who were NOT impaired by their use, and that's a terrible injustice.
Currently many of these convictions are based on metabolite and other tests which may find evidence of prior cannabis use – but which in no way measure any degree of cannabis intoxication or subsequent impairment – and cannabis use effects different people differently based on multiple variables.
So a reliable system doesn't exist yet, and even if cannabis breathalyzers can be made which at least measure current THC levels, they still won't be a complete solution, but they might at least stop many false current convictions.
This surprisingly in-depth article digs into the state of the art from multiple angles….
"A solution for measuring alcohol intoxication has existed since 1954: the Breathalyzer.
No such technology yet exists for cannabis, but several tech startups and university scientists say they're close to commercializing something resembling a cannabis breathalyzer.
Still, others are quick to caution the answer is not that simple. Critics note the technology must detect recent cannabis use and also prove that cannabis in a person's system impaired his or her driving. A cannabis breathalyzer that does both of those things has proven elusive, because, unlike alcohol, cannabis can stay in people's bodies long after their high' has worn off.
'We're applying the alcohol rules to a substance that doesn't play by them,' said Nick Morrow, a retired Los Angeles Sheriff's Department narcotics investigator who now serves as an expert witness in areas such as drug symptomology and field sobriety testing."
Much more in the link…. …recommended reading!
As more states legalize cannabis, health officials are increasingly sounding the alarm for technologies that can quickly determine when drivers are stoned.