Right now, there is none. Obviously the measurable amount isn't reliable - but that has been known to general users for years. And so much of it is personal - a person going out on the weekend and smoking a lot (much like drinking most weekends or occasionally) is going to be really impaired. A regular smoker, who keeps a slight buzz and gets used to it would have very little effect most times. People around them don't have a clue.
I honestly think the best solution would be to regulate the current traffic laws better - including things such as speed limits, yeilding to pedestrians, keeping distance ahead of you (don't know if that is a law) and other things. Not only is this going to help catch people too impaired to be driving, but folks that are simply not paying attention to the road and trying to multi-task while driving.
I honestly think the best solution would be to regulate the current traffic laws better - including things such as speed limits, yeilding to pedestrians, keeping distance ahead of you (don't know if that is a law) and other things. Not only is this going to help catch people too impaired to be driving, but folks that are simply not paying attention to the road and trying to multi-task while driving.