Here’s the problem with these laws: There are questions about how, and at what level, cannabis use impairs driving ability. For a patient in one of the 17 states where marijuana has been legalized for medicinal use, how are you to know when it’s legal to drive? After consuming marijuana, should you wait 12 hours to drive or one day? When will your THC level be below the 5-nanogram threshold? The answer is complicated.Of course it's complicated.
It's complicated for alcohol use too. But we don't care. We're more interested in posting up big numbers of "busts", along with the fines, forfeiture, jailings and fees that all of this police-state tactical response produces. Roadblocks, random sobriety checkpoints and similar are more intended to "show force" than they are to actually get impaired drivers off the road.
If we manage to decrease the crash rate somewhat while applying the boot to the neck of the citizens then that's a nice side effect.
This is exactly backward.
There are already commercially-available reaction time testers that measure actual hand-eye coordination and thus impairment. They map very well to driving ability and are roughly like a small handheld video game.
Equipping police departments with these would provide actual evidence of impairment and be cause-neutral. Whether your impairment was caused by weed, booze, lack of sleep, prescription pills or simply old age, you either can react quickly enough to drive competently or you cannot.
The test is objective and maps to the actual skill required to operate at a reasonable level of safety.
This means, of course, that it would "catch" a lot of people who shouldn't be on the road but are, and many of them would be caught for reasons other than "intoxication" per-se. But this is how it should be -- we should be insisting on a basic level of ability irrespective of how it is achieved or what substance(s) you might have -- or not have -- in your body.
This has not been adopted by the States and local "peace officers" because we no longer have peace officers -- we now have "law enforcement" which is only interested in the public peace as a side effect rather than as the goal of their job.
As a nation, as a people, we can and must do better.
The jackbooted statist parties (Democrat and Republican) won't propose and work to pass this. They clearly consider public peace a side effect rather than a goal.
But the Libertarians have no excuse in this regard.