Do all cars have speed governors?

No—while most modern cars include some form of electronic speed control, not all vehicles have a hard speed governor. Many contemporary passenger vehicles use software to cap top speed (often tied to tire ratings or brand policy), and every modern engine has a rev limiter. However, mandatory speed limiters are typically confined to specific markets and vehicle classes—such as heavy trucks in the EU and Australia—while in places like the U.S. there’s no federal requirement for passenger cars to be governed.

What counts as a “speed governor” today?

A speed governor is any system that limits how fast a vehicle can go. In today’s cars, that can mean several things: a top-speed limiter that cuts power once a set velocity is reached; an engine rev limiter that prevents over-revving; or advisory systems like Intelligent Speed Assistance (ISA), which warns and can gently intervene but doesn’t enforce a hard cap. Mechanical governors were once common on older diesels and buses; now, software in the engine/transmission control units does the work.

Where speed governors are mandatory

Some regions legally require speed limiting on certain vehicle types or through specific safety technologies. The following examples outline the most notable mandates around the world.

• European Union (EU): Heavy goods vehicles and buses must be fitted with limiters (typically 90 km/h for trucks and 100 km/h for coaches). Additionally, Intelligent Speed Assistance (ISA) has been mandatory for new models since July 2022 and for all newly registered vehicles since July 2024. ISA is advisory by default and can be overridden; it is not a fixed speed cap.
• United Kingdom: Mirrors EU practice for heavy vehicles and has adopted the EU-origin ISA requirement through post-Brexit regulations for new vehicles placed on the market, with specifics managed via UK type-approval frameworks.
• Australia: Heavy vehicles over certain mass thresholds are required to be speed-limited to 100 km/h under national design rules (e.g., ADR 65/00), widely enforced across states and territories.
• Japan (domestic market): Passenger cars have long been electronically limited around 180 km/h as part of industry practice and regulatory expectations; heavy vehicles and buses are also governed. ISA-style features are increasingly available but, like elsewhere, function as assistance rather than a hard cap.
• India: Speed limiting devices are mandated for many transport-category vehicles, commonly capping at 80 km/h (and lower for specific uses such as school buses), though enforcement and exemptions can vary by state and vehicle class.

These rules aim to curb extreme speeds and improve safety in higher-risk fleets, but they do not universally impose hard top-speed caps on all passenger vehicles.

Where governors are common but not legally required

Automakers and fleets often install or enable limiters for safety, tire-rating compliance, branding, or operational control—even when the law doesn’t force them to do so.

• Brand policies: German marques have traditionally limited many performance models to 250 km/h (155 mph). Volvo caps all new cars at 180 km/h (112 mph) globally. Other brands vary by model and market.
• Tire and hardware protection: Many trims are electronically limited in line with tire speed ratings (e.g., base models on H-rated tires might cap near 118 mph, while performance variants on Y-rated tires allow higher speeds).
• Electric vehicles: Software caps may reflect drivetrain thermal limits, tire ratings, and stability considerations; top speed varies widely by model.
• Fleets and rentals: Companies frequently set conservative limits to reduce risk, manage fuel and maintenance costs, and comply with corporate policies.

In practice, even without a legal requirement, electronic caps are widespread because they manage safety risks and align performance with component limits.

Where hard speed governors are uncommon

In the United States and Canada, there is no federal requirement for speed limiters on passenger cars. Most modern cars still have electronic top-speed settings and universal rev limiters, but a legal mandate is absent. Heavy trucks are a moving regulatory target: U.S. federal agencies have explored requiring speed limiters on large commercial vehicles, yet as of 2025 no final nationwide rule is in force. Many trucking fleets nonetheless use governed speeds by policy.

Types of speed limiting technologies

Modern vehicles may include more than one speed-control system. Here’s how the main categories differ and where you’ll encounter them.

• Mechanical governors: Older buses and diesel engines used centrifugal or vacuum devices to cap speed—now rare outside legacy fleets.
• Electronic top-speed limiter (Vmax): The ECU reduces power or fuel once a threshold speed is reached; thresholds vary by trim, tires, and market.
• Rev limiter: Protects the engine by cutting fuel/spark at a set rpm; nearly universal on modern engines but not a vehicle-speed cap.
• Intelligent Speed Assistance (ISA): Uses maps/camera data to recognize limits and warn or gently slow the car; typically overridable and advisory.
• Geofenced/fleet limiters: GPS-based caps or telematics-controlled limits common in commercial and municipal fleets.
• Driver-selectable limit: Some cars offer a “LIM” or “Speed Limiter” mode that lets drivers set a ceiling for everyday driving; this is not a factory top-speed cap.

Together, these systems shape how fast a vehicle can travel or how readily a driver can exceed posted limits, balancing safety, hardware protection, and regulatory compliance.

How to tell if your car has a speed governor

Because most controls are software-based, the easiest way to check for a top-speed cap is to consult documentation and onboard settings before resorting to testing on a track.

1. Owner’s manual and spec sheet: Look for “maximum speed,” “Vmax,” “speed limiter,” or tire-rating notes.
2. Onboard menus and apps: Some brands (e.g., Ford MyKey, GM Teen Driver, Tesla Speed Limit Mode, BMW/Mercedes LIM features) expose speed-control settings.
3. Dealer or manufacturer support: Service advisors can confirm market-specific caps tied to VIN, trim, and tires.
4. Diagnostic tools: OBD-II scan equipment and manufacturer software can read limiter parameters in the ECU.
5. Fleet manager/rental agreement: Policies often specify governed speeds or telematics controls.
6. Tire sidewall ratings: Lower speed-rated tires typically correspond to lower electronic caps.

Avoid public-road “testing.” If verification is needed beyond documentation, use a closed course with proper safety measures.

Can you remove or raise a speed governor—and is it legal?

Aftermarket tuners can often adjust or remove electronic top-speed limits, but legality and safety are major concerns. In jurisdictions that mandate limiters (e.g., EU heavy trucks, Australia heavy vehicles, many Indian transport vehicles), tampering is unlawful. Even where it isn’t explicitly illegal for passenger cars, altering ECU software can breach warranty terms, run afoul of insurance policies, and—if emissions or OBD functions are affected—violate environmental laws (notably the U.S. Clean Air Act). Exceeding tire speed ratings is dangerous and may expose you to liability in a crash.

Key takeaways for owners

If a limiter is required by law for your vehicle class, don’t modify it. If it’s manufacturer-set, weigh the safety, component limits, and warranty implications before considering changes—and keep speeds within your tires’ certified ratings.

The bottom line

Not all cars have hard speed governors, but most modern vehicles incorporate electronic controls that limit top speed, protect engines, or assist with posted limits. Whether your car is governed—and to what speed—depends on where you live, what you drive, and how it’s equipped.

Summary

Most modern cars have some form of speed control, but universal hard governors are not the norm. Mandates exist for heavy vehicles in regions like the EU and Australia, and advisory ISA is now standard on new cars in Europe. In markets such as the U.S., passenger cars aren’t legally required to be governed, though manufacturers and fleets often impose electronic caps for safety and hardware reasons. Always check your vehicle’s documentation, respect tire ratings, and be mindful of legal and warranty risks before attempting any changes.

How do I know if my car has a speed limiter?

How do I know if my car has a speed limiter? Most limiters are controlled by buttons on the steering wheel or on an indicator stalk. They are usually activated by pressing a button with the letters ‘LIM’ or one of several similar symbols.

What vehicles have speed governors?

It is commonly used in commercial vehicles, such as trucks and buses, to enhance safety, improve fuel efficiency, and comply with regulatory requirements.

• Vehicle maximum speed can be managed with a speed governor.
• A predefined speed limit will be set on the speed governor.

Do all cars have speed limiters?

No, not all cars have speed limiters; while many modern vehicles incorporate speed-limiting systems, especially for safety and efficiency, the presence and type of limiter vary significantly. A mandate requires speed limiters in all new cars in the European Union, but this is not yet a universal requirement for all new vehicles globally. 
Types of Speed Limiters

• Engine-based (Rev Limiters): Opens in new tabMany vehicles have a rev limiter that prevents the engine from exceeding a certain number of revolutions per minute (RPM), which indirectly limits top speed by cutting fuel supply to the engine. 
• Vehicle-based (Speed Limiters): Opens in new tabElectronic systems limit the vehicle’s maximum speed, often for safety reasons, such as to protect small engines or to ensure tires are not overstressed. 

Mandatory Speed Limiters 

• European Union: As of July 2024, all new cars manufactured for sale in the EU are required to have an Intelligent Speed Assistance (ISA) system. This system uses technology like GPS and traffic sign recognition to enforce local speed limits.

Factors Determining Limiter Presence

• Vehicle Type: Opens in new tabCommercial and heavy-duty vehicles, like trucks and fleet vehicles, are more likely to have speed limiters for reasons of efficiency, emissions, and safety. 
• Vehicle Age: Opens in new tabOlder cars, particularly those from before the widespread adoption of complex engine management systems, may not have electronic speed limiters. 
• Vehicle Purpose: Opens in new tabSome smaller, economy-focused cars or vehicles designed for specific purposes may have limiters to manage power output or enhance stability. 
• Safety Standards: Opens in new tabSafety bodies like the NTSB in the U.S. have pushed for speed limiters on heavy vehicles and are considering wider implementation. 

How Limiters Work (ISA)

• Warnings: The system may provide audible or vibrating warnings to the driver. 
• Haptic Feedback: The accelerator pedal may provide haptic feedback to the driver. 
• Speed Control: The system can actively reduce the vehicle’s speed by cutting power to the engine. 

Driver Override 

• In many systems, particularly the ISA systems in the EU, drivers can override the limiter by applying extra pressure on the accelerator pedal.

Do all cars come with a governor?

A governor or speed limiter prevents a vehicle from accelerating faster than a programmed threshold. Cars sold in the US have speed governors that have been installed by the manufacturer.