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 Rhode Island, a person found in a parked vehicle who is suspected of being under the influence may be subject to a police investigation. Rhode Island law considers someone to be driving under the influence (DUI) if they are in physical control of a vehicle with a blood alcohol content (BAC) of 0.08% or higher. Physical control can include situations where the person is not actively driving but has the potential to operate the vehicle, such as sitting in the driver's seat with access to the keys. Factors influencing whether a person is deemed to be in physical control of a vehicle include their location in the car, whether the engine is running, their state of consciousness, and the position of the keys. If the police find that the individual has been operating the vehicle or has the potential to do so while impaired, they may request a breath or blood test and conduct field sobriety tests. Refusal to submit to a chemical test can result in license suspension. Depending on the outcome of these assessments, the individual may be arrested for DUI. It's important to note that simply sleeping it off in a car does not guarantee immunity from DUI charges if the circumstances suggest control over the vehicle.