If they're in the driver's seat
Does either country really want truck or car drivers driving a vehicle after or while they are smoking pot or for that matter drinking alcohol?
Alcohol has a short term affect. Put the individual in the drunk tank tonight and by morning they'll have a hangover but the effects will be diminished and gone by 48 hours.
Get bombed on pot and the effects take longer to dissipate. So the influence lasts. Get bombed on pot Friday night, the drug is still in the system Monday when you want to get behind that 18 wheeler and go driving on the interstate next to the soccer mom with her 3 kids.
Get smashed on alcohol on Friday night puke all Saturday, sober by Sunday night ready to function on Monday. Sure you may want another drink but the effects of Friday are gone.
Do I care if you partake of the locally legal drug? no.
But one of the affects I have seen is it is getting more difficult to find truck drivers who can pass the drug test.
So as we relax the rules are we ready to relax the testing of truck drivers?