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 Tennessee, DUI laws are strict and can apply to individuals who are in physical control of a vehicle, even if they are not actively driving. This means that a person who decides to 'sleep it off' in their car after drinking may still face DUI charges if they are deemed to be in control of the vehicle. Factors that law enforcement may consider include the person's location in the car (driver's seat vs. passenger seat), whether the engine is running, the individual's state (awake or asleep), and the position of the keys. If the police find someone in a parked car and suspect they have been drinking, they may conduct a welfare check, which can lead to questioning, sobriety tests, and potentially a breath or blood test. If the evidence suggests the person was in control of the vehicle while under the influence, they may be arrested for DUI. It's important to note that simply being present in a vehicle does not automatically result in a DUI charge; the totality of the circumstances will be considered. However, the risk of a DUI arrest is present even for those who have not driven the vehicle but are in a position to potentially operate it while impaired.