Vehicles Testing refers to performance tests on small vehicles, endurance tests, functional tests and lifetime tests on vehicles and vehicle components including fuel system, cooling system, brake system, electrics/electronics, and heating/air conditioning system. Vehicle testing is mandated by the government in which a vehicle is inspected to make sure that it conforms to certain regulations. Vehicle testing also extends to heavy-duty diesel transient exhaust emission testing or medium-duty diesel transient exhaust emission testing. Vehicle testing takes into account test applications, exhaust emission testing, fuel consumption tests, injection fine tuning and environmental tests. Vehicle testing can be required at various times, periodically or on transfer of title to a vehicle. An inspection decal or inspection sticker is placed on the vehicle's windshield when it passes inspection.