You haven't searched hard:

Consider the negative effects of high nervousness on driving skills, the nervousness-reducing effects of alcohol, the side effects of alcohol withdrawal on alcoholics, and the mediating effects of high body mass on the effects of alcohol:

A severely obese alcoholic who is nervous enough about driving and suffering from the shakes might perform worse stone-cold sober than he does with the moderate BAC that he has after drinking a six-pack.

What are the odds that there exists at lease one sufficiently obese alcoholic who is nervous about driving?

That data point would not provide notable evidence that alcohol improves driving in the general population.