A speed limiter prevents a vehicle from exceeding a set speed.

 

Although the driver uses the accelerator, if the vehicle reaches the limited speed, then pressing the pedal normally will have no effect: the limiter will prevent the car from going any faster.  Vehicle speed limiters are one of the most effective solutions for ensuring a vehicle stays within the speed limit.

 

It is basically a safety device that makes long journeys more manageable. It relieves you of the need to constantly check your speed by restricting the ability to exceed the speed limit (or any other speed you may set). Additionally, you're less likely to speed and earn penalty points.