another useful tactic for the mildly drunk driver is to have a can of beer right in your car and take a sip right before they breathalyze you.
this might sound counterproductive at first, but the idea is that breathalyzers are only accurate if there is no residual alcohol in the mouth. this is why the police ask you if you have taken a drink within the last 30 minutes. so, if you take a sip, they have to wait at least another 30 minutes and possibly longer before they can get another reading.
in the meantime, you pray that your body enzymes break down the remaining alcohol in your blood stream fast enough to take you below the legal limit ...