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Guide to Unlawful Vehicle Modifications: State Laws

Whether subtle or drastic, some vehicle modifications are illegal. Certain modifications are less obvious, like a window tint. Other customizations, such as a loud exhaust system or custom lighting, are hard to miss and can be easily heard or seen on public roads.

It is important to understand the laws in your state before customizing your car. This will ensure you don't complete an expensive modification you can't legally enjoy on public roads. It may also help you avoid a ticket from a police officer.

This article and linked materials will help you learn about:

  • Requirements for ground clearance
  • Decorative license plate restrictions
  • Restrictions on loud exhaust systems, muffler mods, and other engine modifications
  • Environmental and emissions standards and how they affect rolling coal modifications and cold air intake
  • Tinted windows and rules for side windows, front/back windows, rear windows, and windshields
  • Radar detectors, radar jammers, and laser jammers
  • Restrictions on tail light tinting
  • Mimicking emergency vehicles with red/blue lights or flashing lights
  • Decibel limits and noise level violations
  • Nitrous Oxide System or NOS (typically legal on a racetrack or off-road, but most states forbid use on any public roads or highways)

Each state has different laws and regulations. Fines also vary from state to state. The chart in this article includes each state's automotive modifications and vehicle equipment laws.

Stock vs. Modified Vehicles

"Stock" and "modified" are terms commonly used to describe the state of a vehicle. They characterize the extent a vehicle has been altered from its original factory specifications.

  • stock vehicle is in its original condition as it came from the factory. It has not undergone any significant modifications. Stock vehicles typically meet the safety, emissions, and legal standards set by the manufacturer and relevant authorities. They are also generally covered by manufacturer warranties.
  • modified vehicle has undergone modification or upgrades beyond its original specifications. Depending on the specific modifications, a modified vehicle may no longer meet factory standards, including safety, emissions, or legal requirements. It may also be unlawful under state law. Modifications may also void some manufacturer warranties.

Aftermarket Modifications: What to Know

Aftermarket car modifications are enhancements made to a vehicle's parts or systems after it has left the factory. These modifications can include changes to any of the following components:

  • Engine
  • Exhaust
  • Suspension
  • Body
  • Interior

Aftermarket modifications offer the chance to customize a vehicle's performance or appearance. Be aware of several factors before making changes:

  • Not all modifications may be legal in your state.
  • Some may void your vehicle's warranty.
  • Poorly executed modifications can compromise the safety of the vehicle and its occupants.
  • The quality of aftermarket parts and installation varies. Carefully research and choose reputable sources to ensure your modification meets legal and safety standards.

What Police Look For

If you have modified your car, it may give an officer a valid excuse to pull you over. There are several modifications that officers look for on public roadways:

Most officers are looking for:

  • Sound and noise level modifications, like exhaust over 95 decibels
  • Frame and suspension mods
  • Engine modifications
  • Aftermarket lighting
  • Window tinting

Traffic laws vary from state to state, but those listed above are the most typical.

The easiest way to avoid the police for this issue is to not modify your car. However, if you are cited for an unlawful modification, you may be able to remedy the situation. Read on to learn more.

Penalties for Unlawful Vehicle Modifications

Car owners can receive a mechanical violation traffic ticket for an unlawfully modified vehicle. In some states, citations for certain unlawful vehicle modifications are considered "fix-it" tickets or "correctable violations."

In California, for example, if you are given a fix-it ticket by a police officer, "yes" will be checked next to Correctable Violation. After the problem is fixed, like removing illegal under-car lights, you must get the signature of an authorized person such as a local law enforcement officer on the Certificate of Correction portion of the ticket.

If you are issued a fix-it ticket for an unlawful vehicle modification in your state, read the ticket to determine whether you can mail the proof of correction, rather than taking it to court.

If the court accepts your correction, the case will be dismissed. If you fail to fix the problem quickly after receiving a fix-it ticket, you will need to pay the fine. You may also be issued another ticket, which can go on your driving record.

Separate Potential Penalties

Even if a vehicle modification is legal, driving with questionable vehicle modifications may result in separate legal charges.

For example, if you installed smoked taillights on your car, it might give a law enforcement reason to pull you over. If you happened to be driving over the speed limit, the officer could write you a ticket for speeding even if they could not legally ticket you for your taillight tint.

Unlawful Vehicle Modifications and State Laws

Different states have varying levels of regulation for car modifications. Use the chart in the following section to check your state's laws before making any custom modifications to your vehicle. Car modification laws can also change over time. Staying informed about the latest regulations is key to avoiding legal issues.

California is known for having the strictest car modification laws. The California Air Resources Board (CARB) oversees controlling and limiting air pollution.

CARB closely monitors “aftermarket" parts (parts not originally manufactured by the vehicle's original equipment manufacturer) before approving what will be installed on any vehicle. This applies to exhaust systems, cold-air intake, or other modifications that may affect fuel economy or emissions.

Other states known for strictly regulating car modifications include:

  • New York
  • New Jersey
  • Massachusetts
  • Pennsylvania
  • Texas
  • Washington
  • Oregon
  • Illinois

Conversely, states with less regulation for car modifications include:

  • Mississippi
  • South Dakota
  • Wyoming
  • Missouri
  • Arizona
  • Idaho

While these states may have more lenient regulations, they may still require certain safety and equipment standards.

Unlawful Vehicle Modifications: State Law Chart

Find links to the relevant laws in your state in the chart below.

State Statute
Alabama Regulation of Operation of Motor Vehicles: Equipment (AL Code Title 32, Ch. 5, Article 9) Window Tinting (AL Code Title 32, Ch. 5, Article 215)
Alaska Vehicle Equipment Standards (AK Statutes section 28.05.081)
Arizona Equipment (ARS Title 28, Ch. 3, Article 16 scroll to sections 28-921 to 28-966)
Arkansas Size and Load Regulations (AR Code Title 27, Ch. 35) Equipment Regulations (AR Code Title 27, Ch. 37)
California Division 12 — Equipment of Vehicles (CA Vehicle Code, Division 12)
Colorado Regulation of Vehicles and Traffic: Equipment (CRS Title 42, Article 4, Part 2)
Connecticut Motor Vehicles: Equipment (GSC Ch. 246; scroll to sections 14-80 to 14-106)
Delaware Equipment Requirements (DE Code Title 21, Ch. 43, Subchapter I) Lights (DE Code Title 21, Ch. 43, Subchapter II)
District of Columbia Regulation of Traffic (D.C. Code Title 50, Subtitle VII, Ch. 22)
Florida State Uniform Traffic Control: Equipment (FS Chapter 316; scroll to sections 316.217 to 316.455)
Georgia Equipment and Inspection of Motor Vehicles (Georgia Code Title 40, Ch. 8)
Hawaii Special Interest Vehicles (HRS section 286-26.5)
Idaho Vehicle Equipment (ID Statutes Title 49, Ch. 9)
Illinois Equipment of Vehicles (625 ILCS 5, Ch. 12)
Indiana Motor Vehicle Equipment (Indiana Code Title 9, Article 19)
Iowa Vehicle Equipment (IA Code Chapter 321, beginning with subdivision titled Lighting Equipment; scroll to sections 321.384 to 321.481)
Kansas Equipment of Vehicles (KS Statutes Ch. 8, Article 17)
Kentucky Vehicle Equipment (KRS Chapter 189; scroll to sections 189.020 to 189.205)
Louisiana Motor Vehicles and Traffic Regulation (LRS Title 32; scroll to sections 32:301 to 32:369) Low-rider vehicles (LRS section 32:297) Proper equipment required on vehicles; display of plate (LRS section 32:53)
Maine Equipment (MRS Title 29-A, Ch. 17)
Maryland Vehicle Laws — Equipment of Vehicles (MD Transportation Code Title 22)
Massachusetts Operation of unregistered or improperly equipped motor vehicles (90 MGL section 9)
Michigan Equipment (MI Vehicle Code sections 257.683 to 257.711)
Minnesota Traffic Regulations: Equipment (MN Statutes Chapter 169; scroll to sections 169.47 to 169.75)
Mississippi Equipment and Identification (MS Code Title 63, Ch. 7)
Missouri Vehicle Equipment Regulations (MRS Chapter 307)
Montana Vehicle Equipment (MCA Title 61, Ch. 9)
Nebraska Lighting and Warning Equipment (R.R.S. Nebraska Statutes Chapter 60, Article 6q)
Nevada Equipment of Vehicles (NRS sections 484D.230 to 484D.545)
New Hampshire Equipment of Vehicles (NH Statutes Chapter 266)
New Jersey Motor Vehicle Equipment (NJ Statutes Title 39, Ch. 3, Article 3)
New Mexico Motor Vehicles: Equipment (NMS Ch. 66, Article 3, Part 9)
New York Equipment of Motor Vehicles and Motorcycles (NY Vehicle & Traffic Code Title 3, Article 9, Section 375)
North Carolina Motor Vehicle Act: Equipment (NCGS Ch. 20, Article 3, Part 9, scroll to sections 20-122 to 20-137)
North Dakota Equipment of Vehicles [PDF] (ND Code Chapter 39-21) Size, Width, and Height Restrictions [PDF] (ND Code Chapter 39-12)
Ohio Traffic Laws: Equipment (ORC Chapter 4513)
Oklahoma Vehicle Equipment (OK Statutes Title 47; scroll to section 47-12-101)
Oregon Vehicle Equipment Generally (OR Vehicle Code Chapter 815) Vehicle Equipment Lights (OR Vehicle Code Chapter 816)
Pennsylvania Equipment Standards (PA Vehicle Code Chapter 41) Lighting Equipment (PA Vehicle Code Chapter 43) Other Required Equipment (PA Vehicle Code Chapter 45)
Rhode Island Equipment and Accessories Generally (RI Code Chapter 31-23) Lighting Equipment and Reflectors (RI Code Chapter 31-24)
South Carolina Equipment and Identification (SC Code Title 56, Ch. 5; scroll to Article 35)
South Dakota Vehicle and Accessory Specifications (SD Codified Laws Chapter 32-15) Wheels, Tires, and Special Vehicles (SD Codified Laws Chapter 32-19) Weight, Size, and Load Restrictions (SD Codified Laws Chapter 32-22)
Tennessee Equipment — Lighting Regulations (TN Code Title 55, Ch. 9)
Texas Vehicle Equipment (TX Transportation Code Chapter 547)
Utah Vehicle Equipment and Modifications (UT Code sections 41-6a-1603 to 41-6a-1641)
Vermont Operation of Vehicles: Equipment ( VT Statutes Title 23, Ch. 13, Subchapter 14)
Virginia Motor Vehicle and Equipment Safety (VA Code Title 46.2, Ch. 10)
Washington Vehicle lighting and other equipment (RCW Chapter 46.37)
West Virginia Equipment (WV Code sections 17C-15-1 to 17C-15-50) Unsafe and improperly equipped vehicles (WV Code section 17C-15-1)
Wisconsin Equipment of Vehicles (WI Code Chapter 347)
Wyoming Equipment (WY Statutes Title 31, Ch. 5, Article 9)

Ticketed for an Illegal Car Modification? Get Help

Consider your legal options if you've gotten a citation for an unlawful vehicle violation. Consulting with an experienced traffic ticket attorney in your area may help you avoid a costly fine. An attorney familiar with local laws for modified vehicles can assess if law enforcement applied the law correctly.

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