Agreed that eliminating drunk and impaired driving is important. (For example, if there was a well-tested and reliable technology that could reduce drunk and impaired driving, I would be in favor of mandating it in new cars.)

But this is not mutually exclusive. For one thing, we can do two things at once. For another, automobile fatalities typically have multiple contributing causes. If we had stronger safety regulations around vehicle height, stopping distance, windshield visibility, etc then some number of the crashes involving alcohol or drug use might have been injuries or close calls instead of fatalities.