Quote Originally Posted by HighPopalorum
alcohol-related traffic fatalities have been plummeting ever since. How much of that decline is attributable to the increased ease of prosecution provided by per se laws? I couldn't say.
There are many reasons for this, and drunk driving laws should not constitute the major percentage. Cars are A LOT safer than they were 40 years ago. Guardrails have been built along all major highways, ambulances are faster, emergency health care is better, etc.

It is a fallacy to mistake a correlation for a cause.

It may be safe to conclude that drunk driving laws are sufficient motivation for some not to drive drunk. This is not sufficient to conclude that drunk driving laws have reduced instances of drunk driving.