I think that all alcohol serving establishments should have a check in for car keys at the door and when the patron is done imbibing, they should have to take a breathalyser test to get their keys back. If their blood alcohol level is above the legal limit, the establishment should immediately call a cab for the person and either hold their keys until the next day or mail the patron their keys. The state could even pay for the breathalysers by tacking on an extra fine to those who are convicted of DUI. For those areas where cab service is not available perhaps the person imbibing could write down the name and number of a person who would be able to drive them home if the person imbibing is too inebriated.