A Question of Alcohol

How long does it take for the effects of alcohol to be felt - in terms of diminished brain functioning capacity. Also, how long does it take for the effects to disappear as the blood alcohol level dissipates. Craig Knowles, a NSW Government Minister, was charged with drink driving the other night. In Sydney's The Daily Telegraph this morning it gives a run-down of "The minister's night out" - including that at 11.55pm he recorded an initial concentration of 0.085. The next reading, at 12.24am is 0.06 (at which point he is arrested). At 1.26am he is down to 0.051, and then at 1.39am "He blows 0.044 and is allowed to drive home." Why were the additional readings done post-charge? So he would know when he was again under the lcgal limit and safe for him to drive again? What a difference those last13 minutes makes!!