One thing I like about Arizona is the fact that all rental cars have a yellow tag in the upper left-hand corner of the license plate indicating a "fleet vehicle." When riding, it's easy to notice these tags, which prompt me to avoid the cars that have them! Here in AZ, we have a lot of snowbirds* in addition to a lot of out-of-towners, all of which are likely to not know where the hell they're going. I don't want to be anywhere near these people when they take an exit ramp at the last minute.
*A snowbird is a person who lives in Arizona during the winter months, most commonly senior citizens.