How do speed limiters work?

New European Union rules on speed limiters come into force on Wednesday, requiring that all new cars, vans and lorries are fitted with the technology as standard.

Though these rules are not due to be implemented in the UK, the Department for Transport (DfT) has said that it will be looking at the technology included as part of the EU’s General Safety Regulation (GSR) but that ‘no decision has yet been taken on which elements of the package will be implemented in Great Britain’.

That does mean that the technology could be made a requirement for future vehicles, with some manufacturers already including the systems on their cars. Nicholas Lyes, head of roads policy for the RAC, said: “We urge the Government to be very careful about cherry-picking certain aspects and dropping others. It’s probably also the case that manufacturers won’t be too keen on excluding certain features just from the cars that they sell to the UK market, as this is likely to drive up their costs.”

So what is speed limiter technology?

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Intelligent Speed Assistance (ISA) technology is included as a way of making cars safer, which is why it is being made a requirement as part of the EU’s set of measures designed to improve road safety. The technology uses GPS data alongside traffic sign recognition software to determine the speed limit of the road that the vehicle is travelling on.

In the process, the car’s engine speed will be limited in order to match the speed limit. The system doesn’t operate the brakes but merely uses the engine to slowly decelerate the car.

Can you override it?

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Yes. The system isn’t fully ‘locked’; you’ll be able to override it by firmly pressing the accelerator. However, if the driver consistently does this then an alarm will sound until the vehicle returns to the speed limit. There might also be small vibrations sent through the steering wheel to alert the driver.

Will you be able to switch it off?

Yes. Much like other safety assistance systems – such as lane-keep assist – you’ll be able to switch off the speed limiter function, either through a physical button or a menu within the car’s infotainment display. However, this will be reset each time you turn the car off and on, meaning that you’ll have to press this button after every stoppage if you wish to switch off the system.

Do any cars currently come with intelligent speed assist?

A number of cars already come with this technology fitted. You’ll find it on a number of Ford vehicles, while Volvo has also included the system on much of its line-up in order to better improve their safety,