The intention of the Motor Vehicle Inspection Act was to insure vehicles driven on the state's highways were safe. In five of those states, the inspections are conducted by state employees. The remainder use private garages supervised or audited by the state.
Most states use unarmed, licensed peace officers to supervise the station for the state.
The DPS indicated the success of this program requires constant supervision. The department's two main concerns are to protect customers from being gouged for unnecessary repairs or alterations, and to insure stations are not issuing inspection stickers to vehicles which do not meet standards. In addition to the frequent unscheduled visits by the uniformed troopers, covert operations and the stopping of obviously impaired vehicles are also conducted. Plain clothes troopers will take an unmarked DPS vehicle to stations to observe the inspection process. MVI troopers also work traffic, looking for possible vehicle defects, pulling over drivers, issuing citations if warranted, and investigating the MVI station if the inspection sticker is newly issued.