I don't know where you are posting from, but here in the USA one beer with dinner will not put you over the legal limit. Even for a very petite woman, consuming one beer over the course of a dinner will barely get your BAC above 0.03%. The limit in the USA is 0.08%.
Even if you are in a jurisdiction where one beer puts you over the limit, get real. You are talking about operation of machinery that is highly dangerous when operated improperly. Aircraft pilots are in the same situation, and they are prohibited from any alcohol consumption for 8 hours (or more) before flight. How is your situation as a driver essentially different from that of a pilot? Do you want pilots having a beer with their dinner in the cockpit?
The University of California Statistics Department; where mean is normal, and deviation standard.