Bonoman this isn't directed at you, but I think the BAC in your province of .08 is excessive. Some people aren't obviously going to be 'drunk' if they are at that, but being drunk is not the starting point for being relatively incapable of driving.
Lets assume a fellow is for all intents and puropses drunk after 8 beers. His reading might be .06. How many beers before number 8 were his reflexes affected? He may stop at number 6, knowing he is under the legal limit, assuming he is ok to drive. the law says he is, so he drives. Unbeknownst to him, while he can walk and talk well, his mind is as sharp as he feels it could possibly be. How does he know though that this is actually the case until it is tested? Does it require a car coming at him from a T-Section to test his reaction time? Many things can affect our reflexes. Fatigue, alcohol, stress, distractions and so on. We are affected by alcohol long before we reach 'the drunk stage' and will not have a clue how acutely we have been affected until it is tested. Unfortunately, it is most often tested the hard way when it is going to be tested at all. I just dont think a standardised level of BAC levels is any kind of indication. It has huge room for error and that is even without taking into account what it takes to be actually 'drunk'.