As a result of limits of drug detection applied sciences and the dearth of a consensus threshold to outline impairment, doing checks for drug impairment is difficult. .08 g/mL blood alcohol focus is the edge of impairment for drunk driving in the US. However for driving whereas underneath the affect of medication, there isn’t a comparable nationwide normal. Individuals reply to medicine in a different way every time. Moreover, marijuana and different medicine can linger within the bloodstream for weeks, making them seen in roadside checks even when they now not trigger impairment.