Vehicle inspection is a procedure mandated by national or sub-national governments in many countries, in which a vehicle is inspected to ensure that it conforms to regulations governing safety, emissions, or both. Inspection can be required at various times, e.g., periodically or on transfer of title to a vehicle. If required periodically, it is often termed periodic motor vehicle inspection; typical intervals are every two years and every year. An inspection decal or inspection sticker is a type of sticker placed on the vehicle’s windshield when it passes inspection. Inspection stations are places to drive inside to see if a vehicle passes inspection once a vehicle is due for inspection. Most US inspection decals/stickers display the month’s number and the year.
In some jurisdictions, proof of inspection is required before a vehicle licence or license plate can be issued or renewed. In others, once a vehicle passes inspection, a decal is attached to the windshield, and police can enforce the inspection law by seeing whether the vehicle displays an up-to-date decal. In the case of a vehicle lacking a windshield (e.g., a trailer or motorcycle), the decal is typically attached to the vehicle body or license plate.