Vehicle inspection rules vary from state to state. In Maryland, a vehicle must be inspected for safety when registered, then every couple of years for emissions

Vehicle inspection rules vary from state to state. In Maryland, a vehicle must be inspected for safety when registered, then every couple of years for emissions. In the District of Columbia, there is a safety and emissions inspection every two years. My recollection is that Pennsylvania and Colorado inspect cars every couple of years. In DC the safety inspection is done by the city, elsewhere by approved service stations.