Automotive enthusiasts like to outfit their motor vehicles with aftermarket accessories that increase the performance and capabilities for specific purposes. This could include high performance cars, work trucks, 4x4 vehicles, ect. Many of these aftermarket parts and accessories do not meet motor vehicle safety standards and are not approved by any authority for use on highways.

These parts can either be manufactured and bought from various retailers. They could be custom ordered to fit. They could be designed, built, and installed by a local specialty auto shop or the owner of the vehicle.

These aftermarket parts could include:

  1. Roll cage - A protective structure, usually built from chromoly or mild steel tubing, meant to protect all occupants of the vehicle during a roll-over accident. This could directly affect crumple zones required by motor vehicle safety standards that are meant to absorb energy during a collision.

  2. Custom bumpers - A common upgrade to vehicles that allows mounting of a winch for recovery purposes. Commonly constructed using cold rolled mild steel plate. This also could directly affect crumple zones required by motor vehicle safety standards that are meant to absorb energy during a collision.

  3. Steering and suspension - Common upgrade that increases stability, durability, and safety. Usually changed or modified to accommodate other upgrades, and can significantly change the characteristics of the vehicle and increase payload.

  4. Roof-top tent - A tent usually mounted to the roof of the vehicle, or on a rack mounted above the bed of a pickup truck, made of either hard plastic or vinyl. This could directly affect the stability of the vehicle and raise the center of gravity, therefore possibly exceeding motor vehicle safety standards.

Some states have passed laws that make it a crime to operate a motor vehicle that is "in violation of state or federal motor vehicle safety standards."

For the purpose of federal safety standards

If an individual purchased a new vehicle, and outfitted it with aftermarket parts that are not certified under any motor vehicle safety standard, would their vehicle be in violation of U.S. Motor Vehicle Safety Standards?

Would the driver be subject to criminal charges under state statute?

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2 Answers 2


In Washington, there is no criminal sanction for installing an "aftermarket" product on your vehicle. If we are speaking of non-commercial vehicles, the penalties for violating the various safety regulations is a ticket.

The federal Motor Vehicle Safety Standards can be consulted here. The criminal penalty provisions are here, as authorized by 49 USC 30170 – basically, lying in a report to the government will get you in trouble. You would have to track down all of the provisions in the regulations, but here is the bumper prohibition. The rule prohibits manufacture or importation of a car or a part that doesn't meet the standard. Subsection (b) addresses the "then added later" question, generally saying that there is little prohibition against you tweaking your car. First, if you "had no reason to know, by exercising reasonable care, that the vehicle or equipment does not comply with the standard", you are not subject to penalty. Usually, people have absolutely no reason to know that some part is unsafe, which is not the same as non-compliant, but you might pick up a really cheap bumper having been told that it is cheap because it totally ignores the applicable standards: then you would have reason to know. Used cars and parts are not subject to any federal scrutiny.

The concept of a "vehicle in violation" is a legal misconception. Certain acts violate, objects do not violate. The chokepoint that controls car parts is the "manufacture or sell" part of the law, which prevents Auto Zone from selling you a bumper made of clay (it does not prevent you from installing such a bumper – unless your state has a specific law to that effect). The shop is in violation, not the customer.


Modification can make operating the car a violation of applicable law in

To be allowed to drive a car on a german road, it needs to have a Betriebserlaubnis, which is most akin to a vehicle registration/allowance to operate this specific vehicle. To get this, the car has to comply with §19 StVZO. Typically, an unmodified car has a type certificate of conformity (Typengenehmigung) according to §2 StVZO, which leads to the car getting a rubberstamped certificate as long as it is managing to pass technical inspection.

However, modifying the vehicle can void the Typengenehmigung. In fact, doing many changes automatically does unless the part added either has a special certificate that it is a certified accessory for this type of car or you make an Einzelzulassungsantrag - a request for individual road certification for your specialized modified car. In either case, for anything more invasive than swapping one approved part for another, you need to go through a technical inspection again, and you need those changes registered on the Betriebserlaubnis.

Certain types of additions to the vehicle are also banned in any circumstance, for example, lightbars with blue light, sirens, having invasive changes to the car, and not having those registered on the car's Betriebserlaubnis automatically can void the Betriebserlaubnis, making driving with the vehicle a crime.

Among the parts listed...

  • Installation of a Roll Cage needs to be registered.
  • Custom Bumpers require either certification that it fits the car and often registration as a custom part.
  • ANY change to the steering or suspension needs type certification and registration.
  • Rooftop Tent needs to be registered.

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