Is removing a speed limiter illegal?

It depends on where you are, what you drive, and how the limiter is implemented. In many places, disabling speed limiters on heavy trucks and buses is explicitly illegal; for passenger cars, removing or raising a factory limiter is often not banned on its own but can still violate safety or emissions laws, void warranties, and lead to insurance or inspection problems. The details vary by jurisdiction and whether the limiter is a mandated safety device or part of emissions-related engine management.

How the law treats speed limiters

Speed limiters fall into two broad categories in law: those required by regulation (common on commercial/heavy vehicles and increasingly tied to mandated safety systems), and those installed by manufacturers as a design choice (common on passenger cars). That distinction largely determines whether removal is illegal outright or simply risky.

• When a limiter is required by law (e.g., on heavy trucks/buses), tampering or removal is typically illegal and subject to fines, vehicle impoundment, and operator sanctions.
• When a limiter is part of a mandated safety feature (e.g., Intelligent Speed Assistance in the EU), disabling it is unlawful and can cause a roadworthiness or inspection failure.
• When a limiter is a manufacturer choice on a passenger car, defeating it may not violate a specific statute by itself, but the methods used (engine control “tunes,” defeating diagnostics) can breach emissions laws, invalidate insurance, and fail inspections.
• Company or fleet policies can make removal a firing offense or breach of contract even if not criminally illegal.

In practice, the legality hinges on whether the limiter is legally required on your vehicle class and whether modification interacts with other regulated systems like emissions or onboard diagnostics.

Regional overview

United States

For passenger vehicles, there is no federal requirement to fit a speed limiter, so raising or removing a factory governor is not, by itself, a federal crime. However, tampering with engine control software in ways that affect emissions systems is illegal under the Clean Air Act, and many “tunes” used to remove limiters also alter emissions or diagnostics, which can lead to substantial penalties. For commercial motor vehicles, carriers often impose limiters by policy or telematics; defeating them can violate company rules and insurance terms. A long-discussed federal rule to mandate limiters on certain heavy trucks had not been finalized as of late 2024; some states can apply their own safety or equipment rules, and tampering could be cited under general unsafe equipment laws or during inspections.

European Union

Speed limiters are firmly regulated. Heavy goods vehicles and buses must be limited (commonly 90 km/h for trucks and 100 km/h for coaches), and tampering is illegal. Additionally, Intelligent Speed Assistance (ISA) became mandatory on new vehicle types from July 2022 and on all newly registered vehicles from July 2024 under the General Safety Regulation. ISA must default to “on” at each restart, and disabling or removing such safety systems can be unlawful and cause a roadworthiness test failure.

United Kingdom

Heavy goods vehicles are limited (typically 56 mph/90 km/h) and tampering is illegal, risking fines and operator licence consequences. The UK is implementing a package of advanced safety features similar to the EU’s, including ISA, for new vehicle types from 2024 with phased timelines thereafter; interfering with mandated safety systems can make a vehicle unroadworthy and unlawful to operate. Passenger cars with manufacturer-imposed limiters may be modified only within the bounds of construction and use regulations, approval rules, and insurance requirements.

Canada

Ontario and Quebec require heavy trucks to have limiters set to 105 km/h; tampering can result in fines and roadside enforcement action, including impoundment. Other provinces do not universally mandate limiters on passenger vehicles. As in the U.S., emission-control tampering is illegal, and inspection programs can flag modified ECUs or diagnostics.

Australia

Heavy vehicles are covered by national rules: speed limiters are mandated (generally 100 km/h) under Australian Design Rules for heavy goods vehicles and omnibuses, and tampering is an offence under the Heavy Vehicle National Law. Passenger cars do not have a general limiter mandate, but modifications that affect emissions compliance, safety systems, or type-approval can be unlawful and fail roadworthiness checks.

New Zealand

Heavy vehicles are required to have speed limiters (commonly 90 km/h for heavy goods vehicles and 100 km/h for certain buses), and tampering breaches the Land Transport Rules with associated penalties. Passenger cars are not generally required to have limiters, but any modification affecting safety or emissions can trigger compliance and certification issues.

Consequences of removing a limiter

Even where not expressly illegal, defeating a limiter can create cascading legal, financial, and safety consequences.

• Fines, impoundment, or operator sanctions if the limiter is mandated for your vehicle class.
• Inspection/MOT/WOF failure if safety or emissions systems are altered or warning lights/diagnostics are affected.
• Insurance denial or policy cancellation if an undisclosed performance modification contributes to a crash or claim.
• Warranty voidance and manufacturer refusal to service powertrain or related components.
• Civil or criminal liability exposure if a crash is linked to an unlawful modification.

In short, removal can cost far more than the modification itself—through enforcement, repair, and liability outcomes.

When removal is more likely to be lawful

There are narrow scenarios where changing a speed limiter does not typically violate laws, provided other regulations are respected.

• Passenger cars without any legal requirement for a limiter, modified without altering emissions systems or mandated safety features.
• Track-only or off-road vehicles that are not registered or operated on public roads.
• Modifications performed within formal certification frameworks (e.g., engineering approval schemes) where allowed, with updated compliance plates or paperwork.

Even in these cases, you must verify local rules, maintain documentation, and inform your insurer to avoid coverage issues.

Practical advice before you modify

If you are considering changing or removing a speed limiter, take these due-diligence steps to protect yourself.

1. Check your jurisdiction’s vehicle code and any commercial-vehicle rules that apply to your vehicle class.
2. Confirm whether your vehicle’s limiter is tied to mandated systems (e.g., ISA, tachograph, heavy-vehicle limiter ADR) that you may not lawfully disable.
3. Avoid any tune or device that alters or disables emissions controls or onboard diagnostics; such tampering is broadly illegal.
4. Notify your insurer in writing of performance modifications and obtain confirmation of continued coverage.
5. Keep all documentation, calibration records, and, if applicable, engineering approvals to demonstrate compliance during inspections.

A brief consultation with a qualified compliance engineer or transportation attorney can save significant expense and legal exposure.

Summary

Removing a speed limiter is often illegal on heavy trucks and buses and increasingly unlawful where safety systems like ISA are mandatory. On passenger cars, raising a factory governor is not always illegal by itself, but the methods used frequently breach emissions or safety rules and can void insurance and warranties. Always verify local law, understand how the limiter integrates with regulated systems, and document any changes before you modify.

Does removing the speed limiter damage a car?

Manufacturers design vehicles to operate within specified speed limits to ensure longevity and reliability. Removing the speed limiter may result in excessive wear and tear, reducing the lifespan of your vehicle and potentially leading to costly repairs.

Can car speed limiters be removed?

Some cars can have the speed limiter removed via diagnostic software such as Ford IDS, Autel or Mercedes Star. Other vehicles can only have speed limiters removed via remapping the ECU. It’s worth remembering that “remapping” is the process of changing the ECU software, NOT improving performance.

Can I remove the speed limiter?

Many cars now offer aftermarket performance chips or engine computer reprogramming that alter the way the engine performs. These modifications can add power or fuel economy to an engine, depending on what the tuner desires. That programming can also include removing the speed limiter.

Are speed limiters mandatory in the US?

The Federal Motor Carrier Safety Administration (FMCSA) has officially withdrawn its proposed rule mandating speed limiters on commercial motor vehicles, effective July 24, 2025, as published in the Federal Register.