It is a criminal offense to use or operate a motor vehicle, boat, airplane, motorcycle, or other motor-propelled vehicle without the consent of the owner or other person authorized to give consent. This crime is generally known as (1) unauthorized use of a motor vehicle, (2) unauthorized use of a vehicle, or (3) joyriding.

The difference between this crime and the crime of theft is that the state does not have to prove a person charged with unauthorized use of a motor vehicle intended to keep the vehicle or permanently deprive the owner of the vehicle.

Laws regarding the unauthorized use of a motor vehicle vary from state to state and are generally found in a state’s statutes—often in the penal or criminal code or the vehicle code.

In Illinois, the unauthorized use of a motor vehicle, commonly referred to as 'joyriding,' is a criminal offense under the Illinois Compiled Statutes. Specifically, the offense is addressed in 720 ILCS 5/21-2, which defines 'Criminal Trespass to Vehicles.' A person commits this crime when they knowingly and without lawful authority enter or operate any vehicle, aircraft, watercraft, or snowmobile. Unlike theft, the prosecution does not need to prove intent to permanently deprive the owner of the vehicle; it is sufficient to show that the vehicle was used without the owner's consent. The offense is typically classified as a Class A misdemeanor, which can result in fines and imprisonment. However, the severity of the punishment can vary depending on the circumstances of the offense and the individual's criminal history.