Lew makes an excellent point, especially that someone near the arbitrary 0.08 percent blood alcohol threshold actually does not know whether he is breaking the law by driving until and unless requested to submit to a test by the government.
I have felt like a similar argument could be made against speed limit laws, as a priori restriction of otherwise moral behavior which is likely to be harmful to no one.
Legalize Drunk Driving by Llewellyn H. Rockwell, Jr.
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