Q: Do All States Require Emissions Testing?

The short answer is – yes, every state requires emission testing. However, there can be a lot of variation from state to state and even within a state. All states require annual or biennial tests, but in many states, testing is limited to certain geographic areas. For example, in New Mexico only one county requires biennial testing, and only if the vehicle is registered in that county. In some states, only vehicles that fall within certain weight categories need to be tested, and vehicles built before a certain model year or older than a certain number of years are exempt. The type of test can also vary from something as simple as a visual inspection that all smog control equipment is in place on the vehicle, to a full engine OBD II function test and tail pipe emissions test with an exhaust gas analyzer. Emission testing is usually in conjunction with vehicle re-registration or resale. For best results, check with your state’s department of motor vehicles or air resources authority.