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 Washington State, the unauthorized use of a motor vehicle, often referred to as 'joyriding,' is addressed under RCW 9A.56.070, which defines 'Taking a Motor Vehicle without Permission.' This statute makes it a criminal offense to intentionally take or drive away any motor vehicle without the permission of the owner or the person authorized to give consent. 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 operated the vehicle without authorization. The crime can be charged as either a first or second-degree offense, depending on the circumstances, such as prior offenses or the value of the vehicle involved. First-degree offenses are more serious and involve factors such as the intent to sell the vehicle, whereas second-degree offenses typically involve temporary use without such intent. Penalties for unauthorized use of a motor vehicle can include imprisonment, fines, and restitution, and the severity of the punishment varies based on the degree of the offense.