BAT is an abbreviation standing for Blood Alcohol Testing. In many cases, mobile DUI vehicles are also called BAT vehicles or BAT / DUI units. This is in direct reference to the way the vehicle is utilized by law enforcement. While officers can pull over a driver and conduct a sobriety test in the field from any law enforcement vehicle, a BAT / DUI unit is unique in that it allows for a more in-depth process to take place. A BAT / DUI vehicle allows law enforcement to test blood alcohol levels without returning to the station. Blood alcohol levels are the determining factor in deciding whether or not someone is driving above the legal limit. Also called, BAC, or blood alcohol content, a BAC of over .08% is considered higher than the legally allowed limit in the United States for drivers.