Now personally I do not think it is at all a good idea to drive when stoned, but I do not consider it anywhere near as dangerous as driving when drunk.
Same goes for a lot of other drugs. I'd rather get in a car with someone driving on LSD than on alcohol. They might think the other cars are penguins, but their reaction time if the penguins get too close is still going to be reasonable.
People who drive under the influence of any mind altering substance (be it alcohol or weed) should have their driving privileges taken away
Caffine and most painkillers fall into this definition. I'd rather just replace the ignition system with a short driving game that you have to complete to start the car.
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