SEMA has compiled two guides on how motor vehicle parts are regulated by the federal and state government. The first is a 6-page brochure that provides a concise overview. Click on the link above to download. The second covers the same information but presented in an electronic fashion, below. The information is generally in a question/answer format, with links to resources for more information.

Disclaimer: The information presented here is current at the time of posting and will be updated periodically as warranted, however, manufacturers should always consult the latest published regulations for any recent changes.





Vehicle/Parts Standards (Overview)

Many aftermarket parts are regulated by the National Highway Traffic Safety Administration (NHTSA) based on safety needs. Generally, the agency regulates equipment that is required on all new motor vehicles. Emissions-related parts are regulated by the U.S. Environmental Protection Agency, California Air Resources Board and other state agencies. An aftermarket part may be directly regulated (ex: lighting equipment, tires, mirrors, brake hoses) or it may be indirectly regulated (i.e., a part may not take the vehicle out-of-compliance when installed). In all cases, NHTSA can regulate any equipment that poses a safety concern. States are free to enact equipment regulations which are identical to NHTSA standards 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 auxiliary lighting equipment, noise levels for exhaust and stereo systems, suspension height and window-tinting. It is the responsibility of the manufacturer to be aware of federal and state laws and regulations in order to meet compliance requirements.




Emission Standards

Emissions-related aftermarket 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). California is unique among the states because Congress granted it the right to regulate emissions independent of the EPA. Parts and components affecting motor vehicle emissions are subject to anti-tampering laws, and require testing and certification. SEMA has compiled a comprehensive “Black Book” to guide members on compliance requirements and how to secure applicable CARB Executive Orders (E.O.s) whereby the manufacturer can demonstrate that its product will not increase the emissions on the intended model year vehicle when installed.



NHTSA Regulations (Overview)

Is there a document which describes how NHTSA rules apply to vehicle and equipment manufacturers?
NHTSA has published a layperson’s guide covering all of the major topics: identifying regulated equipment, certification and marking requirements, registration requirements & forms, defect/recalls investigations. SEMA encourages all equipment manufacturers to review the guide here.

What are the Federal Motor Vehicle Safety Standards (FMVSS)?
The FMVSS are regulations issued by NHTSA that set minimum safety performance requirements for motor vehicles and certain equipment. The FMVSS establish performance requirements without dictating design specifications. The FMVSS are intended to meet the practical and necessary needs of motor vehicle safety. They cover basic safety equipment (e.g. tires, headlamps/tail lamps, brake hoses and brake hose assemblies, etc.) and establish vehicle crashworthiness requirements (front and side impact, roof crush resistance, fuel system integrity, etc.). It is illegal to market a product that does not conform with an applicable FMVSS or would take a vehicle out-of-compliance with a safety standard (“make inoperative”).

Is there a guide which describes the FMVSS and other NHTSA rules?

Quick guide to FMVSS

How can I obtain a NHTSA regulation?

NHTSA’s regulations are published in the Code of Federal Regulations (CFR).

The FMVSS are located at Part 571

Is my company required to register with NHTSA?
Yes, if it manufactures or imports any equipment covered by an FMVSS. There are separate registration requirements for manufacturers of tires, retreads, brake hoses and glazing, since NHTSA also assigns manufacturer identification numbers.

There is a standard registration form for all other equipment manufacturers. Click below for the appropriate category:

What happens when a manufacturer registers with NHTSA?
Registration places the company in NHTSA’s manufacturer database, which is categorized by product type. As noted, NHTSA also assigns an identification number to the manufacturer of certain products (tires, glazing) or accepts a submitted designation (brake hoses).

Are foreign manufacturers required to register with NHTSA?
Yes, all foreign manufacturers, assemblers and importers are required to designate a permanent resident of the United States as the manufacturer's agent for service of all process, notices, orders and decisions. This longstanding requirement applies to all imported equipment, regardless of whether it is covered by the FMVSS. Effective Oct. 1, 2009, the U.S. Customs Service is scheduled to begin using the International Trade Data System (ITDS), a new electronic recordkeeping database. Shipments of all automotive parts (whether or not subject to the FMVSS) will be subject to inspection for proper “Agent for Service of Process” documentation. If the information is not on record, the shipments will be held in the Port of Entry pending submission. The Agent for Service form may be filed online but a signed copy must also be submitted to NHTSA.

For filing instructions, register as the Agent for Service of Process at: and click “Foreign Manufacturer’s Reporting Requirement (and US Agent)” for document type

What is “self-certification”?
When offering a product for sale, the manufacturer is required to certify that the product meets all applicable FMVSS (since it is illegal to market a product that does not comply). Most aftermarket products are not covered by the FMVSS. However, if a product is covered by an industry standard (ex: a wheel standard issued by the Society of Automotive Engineers), it is anticipated that the product will meet the industry standard. Otherwise, the company may risk product liability exposure and NHTSA could deem the product to be unsafe.

How do I certify my product?
Manufacturers must have some reasonable basis for certification but “crash-testing a car” is not required. Certifications may be based on, among other things, engineering analyses, actual testing and computer simulations.

Does NHSTA “approve” vehicles and equipment?
No. NHTSA relies on self-certification. It does not require submission of any documentation regarding the safety of aftermarket parts unless it is triggered by an investigation. Each year, NHTSA crash-tests a limited number of cars manufactured by the automakers to confirm that they meet the FMVSS.

Is “DOT-approved” a legal term?
No, NHTSA has no authority to "approve" or "disapprove" vehicle equipment. The equipment is self-certified. Sometimes the term is confused with the DOT symbol, which is required to be placed by the manufacturer on certain items of equipment such as headlamps. This is simply an affirmative statement by the manufacturer that the equipment is compliant with an applicable NHTSA rule.

Is “For Off-Road Use Only” a legal term?
"Off-road" and "off-road vehicles" are not terms defined in NHTSA regulations and therefore have no legal meaning. Simply stated, the manufacturer cannot control or enforce how the product is used (for off-road use only). Any equipment which is subject to the FMVSS or manufactured to replace equipment covered by the FMVSS must be compliant.

What happens if a product has a defect or is noncompliant?
If a manufacturer determines that a product does not comply with the FMVSS or there is a safety-related defect, the manufacturer must notify NHTSA within 5 days of making such a determination. NHTSA will work with the manufacturer on an appropriate remedy, including notifying distributors, retailers and customers of the problem and remedy for said problem. Safety defects apply to any type of product, not just products covered by the FMVSS. NHTSA also has the authority to conduct its own independent investigations and order a product be removed from the marketplace.

What are “letters of interpretation”?
In most instances, the law or regulation is fairly precise about how a product is regulated (although you may need an attorney to provide guidance). However, there are instances when NHTSA has issued a “letter of interpretation” to further define agency policy on certain issues. These letters are compiled in a single location and can be easily searched by keywords:


Lighting Equipment

How is lighting equipment regulated by the federal and state government?
FMVSS No. 108 establishes performance requirements for basic lighting equipment (headlamps, tail lamps, side reflectors, etc.). A state may regulate equipment not covered by FMVSS No. 108 (“auxiliary lamps”). SEMA has published an article that provides more detail.

How can I obtain a copy of FMVSS No. 108?
The regulation has been amended many times since it was first adopted in 1967 in order to address technological lighting advances. Click below for the most recent version:

Is it legal to sell HID replacement kits?
NHTSA has concluded that it is impossible to produce HID conversion kits (converting a halogen system to HID) that would be compliant with FMVSS No. 108. View more information on HID Conversion Kits.


Tires & Wheels

All tires, from bias ply to radials for all types of vehicles, are regulated under five safety standards: FMVSS 109, 110, 119, 120 & 139.

There are two NHTSA safety standards that reference wheels (rims), FMVSS No. 110 (tire selection/rims for passenger cars weighing less than 10,000 pounds) and FMVSS No. 120 (tire selection/rims for vehicles weighing more than 10,000 pounds). The rules are focused on making sure the vehicle has the proper size tire/wheel combination. They do not establish performance requirements, although FMVSS No. 120 includes marking requirements. Most wheel performance/marking requirements have been accomplished through industry standards established by SAE (Society of Automotive Engineers) and other international organizations. SEMA worked with SAE to develop SAE J2530, “Aftermarket Wheels - Passenger Cars and Light Truck - Performance Requirements and Test Procedures” [Published: April 2016]. NOTE: SAE J2530 establishes performance and marking requirements.


Fuel Economy

Corporate Average Fuel Economy (CAFE) are federal regulations intended to improve the average fuel economy of cars and light trucks (trucks, vans and SUVs) sold in the United States. Fuel economy is defined as the average mileage traveled by an automobile per gallon of gasoline (or equivalent amount of other fuel) consumed as measured in accordance with the testing and evaluation protocol set forth by the EPA. Cars and light trucks have traditionally been held to different CAFE standards. For example, as of 2010, the average for cars must is 27.5 mpg, and the light truck average is 23.5 mpg. However, there have been significant recent changes to the rules. Trucks will have varying targets based on truck size “footprint” as of 2011, and NHTSA will effectively merge the car/truck standards beginning in 2012. The average CAFE rating will be 35.5 mpg in 2016, based on a combined 39 mpg rating for passenger cars and 30 mpg for light trucks. NHTSA will use an attribute-based system which sets CAFE standards for individual fleets of vehicles based on size/footprint. NHTSA and the EPA will also use the CAFE standards as mechanism for controlling carbon-dioxide (CO2) emissions from automobiles since CO2 is released in direct proportion to the amount of carbon-based fuel that is burned.

Recent CAFE Rulemakings
EPA fuel economy ratings (new car window sticker): Questions | Ratings
What you need to know about making fuel economy claims
What are current test parameters for making fuel economy claims