[anon9001]

I'd rather ride with a stoned driver than a drunk driver any day. I'd also prefer a stoned driver over an elderly driver or a sleep deprived driver. And if I had the choice between a totally sober driver or a driver on stimulants, I'd take the stimulant driver.

If this was really about reducing risk on the road, we should somehow incentivize people like OP to work on the self-driving car problem, rather than come up with a device to catch stoned drivers. Think how much brain power and law enforcement time is going to be taken up dealing with stoned drivers. The rational thing to do would be to let people drive stoned, arrest those who are visibly impaired and can't perform a field sobriety test, and focus our efforts on getting AI to replace all human drivers.