This guy in Columbus says no.

Essentially, his viewpoint is that so few people are actually killed by drunk drivers that government shouldn’t be wasting its time on the issue.

While it'd be pretty easy for me to believe the current level of enforcement is too high in the sense that the marginal costs exceed the marginal benefits. It would be hard to accept the notion that the optimal level of DUI enforcement is zero -- even though that is exactly my view on many other issues with supposed negative externalities (e.g., drug use). But now that I'm thinking about it, I wonder...

Thinking like an economist, I wonder what the elasticity of injuries/deaths caused by drunk driving relative to enforcement efforts is. If the elasticity is sufficiently low, the enforcement costs are likely to be high and the benefits in terms of fewer injuries/deaths low...and doing nothing may indeed be optimal.

Here's a bit of the abstract from an academic paper on the question:

Using state level data over the 1975–1986 period, we report no conclusive evidence that any specific form of punitive legislation is having a measurable effect on motor vehicle fatalities. We report suggestive evidence that multiple laws designed to increase the certainty of punishment (e.g., sobriety checkpoints and preliminary breath tests) have a synergistic deterrent effect. The most striking finding is that mandatory seat belt use laws and beer taxes may be more effective at reducing drunk driving fatalities than policies aimed at general deterrence.

"Suggestive evidence" of a "synergistic deterrent" is the best they have? Hmmm.

So a blood-alcohol "cap" probably doesn't work, but an alcohol tax probably does. Forget carbon taxes and global warming, I'll be looking for Greg Mankiw to take up this cause for his Pigou Club.