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 New Jersey, DUI/DWI laws are strict and can apply to individuals who are not actively driving but are deemed to be in 'physical control' of a vehicle. If a person is found by police in a parked car and is suspected of being under the influence, several factors will be considered to determine if they were 'operating' the vehicle. These factors include the person's location in the car (driver's seat vs. passenger seat), whether the engine was running, the person's state (awake or asleep), and the location of the keys. If the individual is in the driver's seat with the keys in the ignition, or if the engine is running, they may be at higher risk of being arrested for DUI/DWI, even if they were not observed driving. New Jersey law enforcement officers have the authority to investigate, conduct field sobriety tests, and request breath or blood tests if they suspect DUI/DWI. An arrest can be made based on the totality of circumstances indicating that the individual was in physical control of the vehicle while impaired.