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 Iowa, the unauthorized use of a motor vehicle, often referred to as 'joyriding,' is addressed under Iowa Code section 714.7. This statute makes it a criminal offense to use or operate any motor vehicle, airplane, motorcycle, motorboat, or any other motor-propelled vehicle without the consent of the owner or the person authorized to give consent. The key distinction between this offense and vehicle theft (grand theft auto) is the element of intent. For a charge of unauthorized use, the state does not need to prove that the individual intended to permanently deprive the owner of the vehicle, which is a necessary element for a theft charge. Unauthorized use is typically considered a lesser offense than theft and may result in different penalties. Penalties for unauthorized use of a vehicle in Iowa can range from simple misdemeanors to more serious felony charges, depending on the circumstances of the offense and the individual's criminal history.