What is a speed limiter?

Stick to the limit without having to check your speedometer with a speed limiter

BuyaCar team
Jun 7, 2018

A speed limiter restricts a car’s mph to one that you specify. Some more modern systems can automatically change a car’s speed in response to speed limit signs. These are often referred to as intelligent speed limiters.

What's the point of a speed limiter?

It’s a safety device, and makes a long journey easier to complete. It relieves you from the need to keep checking your speed, by maintaining a pre-set speed.

It also means that you’re less likely to be caught speeding, as long as you set it to within the speed limit.

What types of speed limiter are there?

Adjustable speed limiter

There are two types of speed limiter available. The first - an adjustable speed limiter - is by far the most common. It's included as standard equipment on most cars, although you may have to pay more for it on some entry-level versions.

The limiter is set by the driver: you select the maximum speed that you want to travel at and then drive normally. If the car reaches that speed, then it won't go any faster, even if you continue to press the acclerator gently.

In traffic, the limiter will remain active as you slow down and speed up but you will need to adjust it if the speed limit changes. You can also override the limiter if you need to speed up quickly, by pressing down hard on the accelerator.

Intelligent speed limiter

Some manufacturers, including Ford, offer the option of a more advanced system on some cars, which links the speed limiter to a camera that can spot speed limit signs. When you drive into an area with a different speed limit, then the limiter is adjusted accordingly.

There's no complete guarantee that the cameras will spot every sign, so you'll still need to pay attention.

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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. Don't get confused with the very similar symbol for cruise control, which is an arrow on a speedometer.

   

What's the difference between cruise control and a speed limiter

When you're using a speed limiter, you are fully in control of the car. You have to keep pressing the accelerator to keep it moving. If you don't, the car will slow down and stop.

Cruise control takes control of the accelerator to maintain a steady speed. You don't need to press it at all, and the car will continue at the same rate. More advanced adaptive cruise control systems can also brake too, enabling them to maintain a set distance from the car in front.

Both systems can be overridden by pressing the pedals or switching them off with the press of a button.

    

What do safety organisations think of speed limiters?

Euro NCAP, which assesses and rates the safety performance of new cars, is an enthusiastic supporter of what it calls ‘voluntary set’ speed assistance systems that help drivers to control their speed. As part of its safety assessment work, it awards points to those cars that have them fitted as standard

It judges systems on how easy they are to use and the clarity of the audible warning they emit when the car exceeds the set speed. In addition, it judges those systems that actively control the car’s speed on the basis of how closely they conform to the limit set by the driver.

    

Are there other types of speed limiters?

High-performance cars often have limiters that control their top speed and limit it for safety reasons. German models are typically restricted to 155mph.

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