An auto inspection is generally required by law to ensure that the vehicles on the road are safe for people and for the environment. Owners are required to take their cars to a shop that specializes in or is licensed to do an auto inspection. Safety inspections check a number of the car's systems, such as brake operation and condition of components, to be sure that the car does not fake a threat to the driver or anyone else on the road. Clean air inspections test the chemical content of the exhaust to ensure that the car's emissions control system is functioning properly. If a car fails an auto inspection for any reason, the owner will be necessary to have the car repaired so that it complies with the inspection's standards.

An auto inspection is also regularly performed prior to purchasing a car. This type of auto inspection ensures that a car will be a good investment for the buyer, and is generally performed by a mechanic that the buyer trusts. These auto inspections usually follow a list of points, such as braking system, cooling system, and so on; this is to ensure that each car gets the same thorough inspection. If any of a car's vital systems shows signs of future or rising problems, the mechanic needs to let the buyer know. A pre-purchase auto inspection can potentially a save buyer from unwittingly buying a car that will end up costing him or her lot of money.