A person who believes they have had too much to drink to safely or legally drive may sit, lie, or fall asleep in their vehicle in a parking lot or parking space outside of a bar or restaurant, or may pull off the road and park to “sleep it off.” When the police observe a person occupying or sleeping in a parked car they may investigate if the car is illegally parked (on the side of the road or elsewhere) or for the stated purpose of checking on the well-being of the occupant of the vehicle.

After knocking on the window and attempting to wake the occupant of the vehicle the police will typically ask if the occupant was recently operating the vehicle and whether the occupant has had anything to drink. Based in part on the occupant’s answers to these questions the police may request the occupant submit to a breath or blood test, perform field sobriety tests, and may ultimately arrest the occupant for DUI/DWI.

Laws defining DUI/DWI criminal offenses vary from state to state and often include a person who is in physical control of a vehicle as being within the definition of operating a vehicle. Based on such a broad statutory definition of operating a vehicle—and depending on other factors such as (1) whether the occupant was in the driver’s seat of the vehicle or the back seat or passenger seat; (2) whether the vehicle’s engine was running; (3) whether the occupant was awake or asleep; and (4) whether the key, if any, was in the ignition—the police may arrest the occupant for DUI/DWI.

In Louisiana (LA), the law considers a person to be in physical control of a vehicle if they have the capability to operate it, which can include situations where an individual is sitting, lying, or sleeping in a parked car. If law enforcement officers find someone in a parked vehicle and suspect they may be intoxicated, they can investigate to determine if the person has been driving under the influence (DUI) or while intoxicated (DWI). Factors such as the person's location in the vehicle, whether the engine is running, the individual's state of consciousness, and the location of the keys can all influence the officer's decision to conduct sobriety tests or make an arrest for DUI/DWI. Louisiana's DUI/DWI laws are broad enough to encompass individuals who are not actively driving but are deemed to be in control of the vehicle. Therefore, even if someone is trying to 'sleep it off' in their car, they can still face DUI/DWI charges if the circumstances suggest they have control over the vehicle and are under the influence.