What is a Speed Limiter and what does it do?
Sometimes called a speed governor, a speed limiter is a device that is installed into a vehicle to limit its top
speed. That top speed is preset on the device, and cannot be overridden by the driver, the aim to provide improved
safety, efficiency and complete compliance with regulatory requirements.
A speed limited can accomplish this in two ways, including adjusting the fuel supply to the engine or controlling
the fuel pump electronically, cutting fuel once the target speed is reached. In some cases, the use of a governor or
speed limiter may be required by law, and it is most commonly used in commercial vehicles , and frequently deployed
by fleet managers too.
Why do Speed Limiters Matter?
Speed limiters can be used for a number of reasons, from promoting driver safety to improving fuel efficiency and
helping the fleet management process.
As an example, a fleet manager may wish to set a maximum speed on their delivery trucks to avoid the delays and
costs of speeding charges and reduce accident risks, while also increasing fuel efficiency and as a result, lower
operating costs.
Remember, a speed limiter is not like a cruise control, it makes the vehicle physically unable to go beyond a set
speed. If it attempts to do so, then the device cuts the fuel supply to prevent acceleration.
Can you remove a Speed Limiter?
Speed limiters are tied into the electronics and fuel systems of a vehicle, as they need to monitor speed and be
able to cut the fuel supply to function. Fitting them is a complex process, and removing them is the same, and
usually needs modifications to the engine control unit .
It needs specialized knowledge and experience to be able to attempt the removal of a speed limiter, but there are 3
ways to accomplish it:
On Board Diagnostics - You can use an on-board diagnostics scanner, called an OBD2 , to change a number of vehicle settings,
including the ability to disable the speed limited.
ECU Programming - You can reprogram the
ECU to either remove the speed limit or change it to a different speed.
Replacement ECU - The final option is to use a replacement ECU that has been adjusted to remove the
speed limiter. These aftermarket ECUs are
available from a number of suppliers.
While these approaches can remove factory fitted speed limiters, you must consider the safety aspects of doing so,
as well as the legality. In some cases, regulations prohibit the removal, and doing so could leave you the wrong
side of the law.
Speed Limiter Rules
Each region has their own rules and regulations regarding the installation and use of speed limiters, and can vary
depending on the type of vehicle involved.
For the two main regions, they are set by:
United States - The Federal Motor Carrier Safety Administration (FMCSA) is responsible for
commercial vehicle legislation, including speed limiters and their use.
European Union - The European Commission passed laws that state that all cars manufactured
after 6 July 2022 must have a speed limiter fitted.
Before operating any vehicle, you should be aware of all laws and regulations covering the use of speed limiters in
that jurisdiction.
Conclusion
Speed limiters offer a very easy way for vehicle owners and fleet managers to control how they are driven . As well
as being required by law in some regions, a speed limiter can not only reduce the risk of accidents, but decrease
fuel consumption, lowering running costs for the vehicle too.
While it is possible to remove speed limiters, it is essential that you check the legality before doing so, as in
many regions, not only is the speed limiter itself compulsory, but having it set to specific speeds is required as
well.