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 Arizona, the unauthorized use of a motor vehicle, often referred to as 'joyriding,' is a criminal offense under Arizona Revised Statutes (ARS) §13-1803, which covers 'Unlawful Use of Means of Transportation.' This statute makes it illegal to knowingly use or take control of another person's vehicle without lawful authority. Unlike theft, the prosecutor does not need to prove that the individual intended to permanently deprive the owner of the vehicle, only that they used or took control of the vehicle without permission. The offense can be classified as a Class 5 felony if the person exercises control over the vehicle, or a Class 6 felony if they simply ride in the vehicle knowing that it is being used without authorization. Penalties for this crime can include fines, restitution, and imprisonment. It is important for individuals charged with this offense to consult with an attorney to understand their rights and the specific implications of the charge.