Mandatory Speed Limiters UK: Cars, ISA & the Law

Speed limiters are not mandatory on cars in the UK. Since July 2024, new cars and vans sold in the EU must have Intelligent Speed Assistance (ISA), and most new cars sold in the UK include it because manufacturers build to a European specification, but ISA is a driver assistance system that can be overridden, not a hard speed limiter. The speed limiter law that is mandatory in the UK applies to goods vehicles over 3.5 tonnes (56mph) and to buses and coaches with more than 8 passenger seats (62mph).

This guide sets out which vehicles need a speed limiter by law, how ISA on new cars works, and what that means for car, van, HGV and PSV fleets.

Are Speed Limiters Mandatory in the UK?

Vehicle type	Speed limiter legally required?	Required setting
Cars	No. ISA is fitted to many new cars but is not a speed limiter	Not applicable
Vans and LCVs up to 3.5 tonnes	No. Fitting a limiter is voluntary	Chosen by the operator
Goods vehicles over 3.5 tonnes	Yes	56mph (90 km/h)
Buses, coaches and minibuses with more than 8 passenger seats	Yes	62mph (100 km/h)

The heavy vehicle requirements sit in the Road Vehicles (Construction and Use) Regulations 1986 (as amended). They were introduced in stages from 1992, and some older vehicles are exempt depending on their registration date. Speed limiters fitted to in-scope vehicles must be type-approved, calibrated, sealed and plated. For the detail, see our guide to UK speed limiter regulations for HGVs and PSVs.

Mandatory Speed Limiters in Cars: What ISA Actually Does

Headlines about “mandatory speed limiters in cars” refer to ISA. It is not a speed limiter in the traditional sense. ISA uses GPS positioning, map data and camera-based traffic sign recognition to work out the speed limit for the road. When the driver exceeds it, the system responds in one of several ways depending on the manufacturer:

• Haptic feedback: resistance or vibration through the accelerator pedal
• Visual and audible warnings: dashboard alerts and chimes
• Gentle speed reduction: a brief, overridable reduction in engine power

The critical point is that the driver can override ISA. Pressing firmly on the accelerator continues past the warning, and the system can be switched off, although it reactivates each time the vehicle is started. This is intentional: ISA is an Advanced Driver Assistance System (ADAS), not an enforcement device.

For a detailed comparison, see speed limiter vs ISA: which do you need.

Speed Limiter Law: ISA and the General Safety Regulation

ISA is required in the EU by the General Safety Regulation (EU) 2019/2144, which applied to all new cars and vans sold in the EU from July 2024. Great Britain has not adopted the ISA requirement. Northern Ireland is in a different position because it continues to follow many EU vehicle rules, so check the current requirements if you register new vehicles there.

In practice, ISA is still present on most new cars and vans sold in Great Britain because manufacturers do not build separate UK-specification vehicles. A new van sold here typically has the same ISA system as its EU equivalent. UK policy could change, so fleet operators should plan on ISA being a permanent feature of new vehicles and keep an eye on developments.

For the EU background, read our EU General Safety Regulation and ISA mandate guide.

ISA vs Commercial Speed Limiters: The Key Differences

Feature	ISA (new cars)	Commercial speed limiter
Can be overridden by driver	Yes	No
Speed reference	Variable (road limit via map data and cameras)	Fixed maximum, e.g. 56mph
Depends on map or sign data	Yes	No
Legal status (UK)	Not required in Great Britain	Mandatory for goods vehicles over 3.5t and PSVs
Tamper evidence	No seals or certification	ECE R89 type-approved, sealed and plated
Fleet compliance value	Advisory only	Demonstrable enforcement

The Override Problem

A driver inclined to speed can simply press through an ISA warning. In a duty-of-care context, an employer relying only on ISA has no evidence that speeds were actually controlled. A sealed speed limiter provides a maximum that cannot be exceeded under power without tampering that would be evident on inspection.

The Data Problem

ISA relies on knowing the limit for every road, which leaves gaps:

• Private land and sites: depots and construction sites often have no map data
• Temporary limits: roadworks are not always reflected in map databases
• Sign misreads: obscured, damaged or non-standard signs can confuse cameras

A commercial speed limiter does not depend on external data.

GPS Speed Limiters and the Law

GPS speed limiters that change the maximum speed by location, such as GeoKontrol 2, are not required by UK law. Fleets fit them voluntarily to enforce their own limits in depots, on sites and in 20mph or school zones. Unlike ISA, the zones are set by the fleet operator and the driver cannot override them. A GPS speed limiter does not replace the fixed, type-approved speed limiter that goods vehicles over 3.5 tonnes and PSVs must have.

What This Means for Car and Van Fleets

For cars and light commercial vehicles up to 3.5 tonnes, ISA is a welcome safety feature but not a speed management strategy:

ISA as a first layer: it gives drivers real-time feedback and may reduce inadvertent speeding.

Voluntary speed limiters for enforcement: fleets that need guaranteed speed control for insurance, duty of care, site safety or fuel management can fit a speed limiter voluntarily. See our guides to voluntary speed limiters for vans and the car speed limiter options available.

Combined approach: the most effective set-up pairs ISA’s road-aware feedback with a fitted limiter that enforces the operator’s absolute maximum.

What This Means for HGV and PSV Operators

ISA changes nothing about existing legal obligations. Speed limiters remain mandatory for goods vehicles over 3.5 tonnes and passenger vehicles with more than 8 passenger seats, and the requirements for type-approved devices, calibration, sealing and plating are unchanged. New trucks and coaches may come with ISA, but it operates alongside the mandatory speed limiter, not as a replacement.

Getting Started

Whether you want to add voluntary speed limiters to a car or van fleet, ensure your HGVs and coaches are compliant, or understand how ISA and speed limiters work together, AutoKontrol has been designing and manufacturing speed limiters in the UK since 1985. Request a free quote to discuss your fleet’s requirements.

Frequently Asked Questions

Are speed limiters mandatory on new cars in the UK?

No. Speed limiters are not mandatory on cars in the UK. Many new cars sold in the UK are fitted with Intelligent Speed Assistance (ISA) because manufacturers build to EU specifications, but ISA is an overridable driver assistance system rather than a speed limiter, and Great Britain has not adopted the EU ISA requirement.

Is ISA the same as a speed limiter?

No. ISA advises the driver of the road speed limit through warnings, pedal feedback or a brief power reduction, and the driver can override or switch it off. A commercial speed limiter enforces a fixed maximum speed that the driver cannot override, and on regulated vehicles it is type-approved and sealed.

Can you turn off ISA on a new car?

Yes. Under the EU General Safety Regulation the driver can switch ISA off, but it must switch back on each time the vehicle is started. The driver can also override it while driving by pressing firmly on the accelerator.

Which vehicles must have a speed limiter by law in the UK?

Goods vehicles over 3.5 tonnes must have a speed limiter set to 56mph (90 km/h), and buses, coaches and minibuses with more than 8 passenger seats must have one set to 62mph (100 km/h). Some older vehicles are exempt depending on registration date. Cars and vans up to 3.5 tonnes do not legally require one.

Is there a speed limiter law for vans?

There is no legal requirement to fit a speed limiter to a van up to 3.5 tonnes in the UK. Goods vehicles over 3.5 tonnes must have one. Many van fleet operators fit speed limiters voluntarily for safety, fuel and insurance reasons.

Do GPS speed limiters replace a mandatory HGV speed limiter?

No. GPS or geofenced speed limiters are a voluntary addition that enforce lower limits in chosen zones. Goods vehicles over 3.5 tonnes and PSVs must still have a type-approved speed limiter set to the legal maximum.