True-you are never a safe driver if you are impaired. tolerance is dangerous because it fools you into thinking you are more sober than you are. tolerance can trick you into believing you are safe to drive when you are not. zero tolerance for impaired driving is the best option.
alcohol tolerance is increased by regular drinking and means that you have to drink more alcohol in order to achieve the same effects as before tolerance was established. however, tolerance has no effect on your blood alcohol concentration (bac). in other words, you may not feel impaired even if your bac is elevated.