Car Inspection Laws

Most states have car inspection requirements to check carbon emission levels, general safety standards, or both—either at regular intervals or for first-time registrants only. Many states with emissions testing (also called a "smog" test) limit it to densely populated metropolitan areas and exclude relatively new vehicles from these requirements. California, for example, requires biennial smog testing only for vehicles older than six model years (all motorcycles are exempt). Regular safety inspections are less common, but most states allow state police officers to inspect a vehicle if they believe it is unsafe.

The following is an overview of laws and requirements for safety and emissions standards, which vary by state. Check with your state's department of motor vehicles for specific requirements.

Car Inspection Laws: Emissions

While car manufacturers must adhere to federal emission standards, cars already on the road are subject to periodic testing, often referred to as a "smog test." Depending on the state, automobiles that fail the smog test may retake it after getting serviced.  Further, they may be classified as "gross polluters" if they produce twice the emissions limit (see California's What is a Gross Polluter? fact sheet), and thus subject to a different testing procedure or be taken out of use permanently.  

Some states have no car inspection mandate for carbon emissions, including Florida, Kansas, Michigan, and South Carolina. Most states with emissions testing requirements vary by county or city, such as Oklahoma, New Mexico, Nevada, Missouri and Indiana. For instance, the most populous counties in Missouri (including St. Louis County and Jefferson County) require biennial inspections for carbon emissions. Still other states require all vehicles to be tested for emissions, including New Jersey and Connecticut.

Most states also have different standards for cars over a certain age. Examples include exceptionally old vehicles (such as classic cars or antiques), as well as certain different types of vehicles (motorcycles, cars, light trucks). Using one state as an example, certain counties in Texas require annual emissions testing for gasoline-powered vehicles between two and 24 years old.

Some states maintain government-operated inspection sites, while others (including California) outsource inspections to private mechanics.

Car Inspection Laws: Safety

Most states allow state police officers to inspect vehicles during roadside stops if they reasonably believe the automobile is unsafe. But some states have certain safety inspection requirements, either for first registrations or on a regular basis. As with emissions testing, many states allow exemptions for newer cars; require safety testing for cars brought in from out of state; or only for the first year of registration.

Standards differ from state to state, so you would need to check with your local DMV for specifics. But generally, car inspections related to safety standards check the following:

• Lights
• Brakes
• Horn
• Windshield wipers
• Seat belts
• Tires

If you fail a safety inspection, typically you will be required to fix your vehicle (get new brakes, replace a burned-out headlight, etc.) before your vehicle license will be renewed. Some states, such as Hawaii, fine car owners who fail a safety inspection. Many states, including Massachusetts, outsource safety inspections to private mechanics.

If You are Buying a Car

For the most part, new cars will far exceed any state's safety emissions standards. But when buying used cars, it is often a good idea to have a third party inspect the vehicle before making the purchase. In some states, the buyer has the option of cancelling the sale of an automobile (new or used) if it fails a required car inspection.