Drunk driving laws are really addressing the problem indirectly. The whole point is that EtOH affects stuff like reaction time, motor control, situational aware

Drunk driving laws are really addressing the problem indirectly. The whole point is that EtOH affects stuff like reaction time, motor control, situational awareness, and risk assessment. The source doesn't matter, if you are not able to meet a minimum ability in those skills, then driving is a going to be dangerous. The source of the problem doesn't matter. Instead of the breathalyzer (or other tests for EtOH) we should be testing for ability. I suspect this shouldn't be hard or expensive, for example, to make a portable device that implemented objective tests[1] of ability. Obviously some research would be needed to determine which skills need to be tested and to calibrate the minimum-ability cutoffs. [1] like this reaction time test: https://faculty.washington.edu/chudler/java/redgreen.html https://faculty.washington.edu/chudler/java/redgreen.html