Emissions and emissions-related parts are regulated by the U.S. Environmental Protection Agency (EPA) and various state agencies, primary of which is the California Air Resources Board (CARB). For products sold in California (and states that have adopted the California standards), manufacturers must conform to standards issued by the CARB.

Federal law prohibits states from issuing motor vehicle safety regulations that conflict with federal standards. This is called federal preemption. However, states are free to enact and enforce safety and equipment regulations which are identical to the FMVSS or, in the absence of a federal rule, establish their own laws and regulations. The most frequent examples of individual state rules cover parts like "optional" or "accessory" lighting equipment, noise levels for exhaust and stereo systems, suspension height, and window tinting. States also establish rules on how a vehicle is titled and registered. State and local jurisdictions have authority to regulate inoperable vehicles or determine whether an enthusiast is engaged in a business vs. private activity. State and local law enforcement officials issue tickets and inspect cars.

State laws have evolved over many generations and they continue to change. Some laws are better than others, and there is a constant need to remind state policy makers not to be biased in favor of the vehicle's original equipment, such as lighting, tires and wheels, suspension components, and bumper/frame height. For example, some state laws allow motorists to be ticketed when an officer has made a subjective noise level determination that the exhaust system is "louder than what came with the car." To cite another example, bills have been introduced in state legislatures to ban spinners even though they are legal at the federal level. Opposing arbitrary and unnecessarily restrictive equipment and inspection laws is a constant challenge.

"Gas Guzzler" Laws
Gas Guzzler laws primarily come out of state legislatures in misguided attempts to reduce greenhouse gas emissions. A bill in New York, for example, seeks to establish a progressive purchase or lease surcharge for some new motor vehicles based on calculations of carbon emissions. Depending on the vehicle purchased, this surcharge could require owners to pay up to $2,500 more for a vehicle. Another bill in New York proposes to create a task force that would recommend higher toll and registration fees for vehicles based on the vehicle's weight, emissions, and fuel-efficiency ratings. In California, a similar measure was recently defeated that would have added a surcharge to some vehicles based on state calculations of carbon emissions. If such an effort was successful, the effects on a consumer's ability to purchase their vehicle of choice, not to mention vehicle safety, would be dramatic. These measures would also make popular performance and luxury cars, as well as SUVs, light trucks, and minivans, substantially more expensive to own without necessarily curtailing greenhouse gas emissions, since greenhouse gas emissions have more to do with overall basic vehicle maintenance than with owning and operating any particular class of vehicle.

Tire Fuel Efficiency: Kick the Tires. Are They Fuel Efficient?
A lot rides on your tires. That will soon include greenhouse gases, namely carbon dioxide (CO2) emissions. Both California and the federal government are pursuing regulations to rate replacement tires for "fuel efficiency" in an effort to influence consumer choice. In theory, if a tire is more fuel-efficient, less gas is burned and therefore less CO2 is emitted into the atmosphere. Some state lawmakers want to go one step further and mandate emissions limits ... within their state boundaries.