With the Federal Motor Carrier Safety Administration once again considering the idea of mandating speed limiters on most tractor-trailers, PrePass examines use of the devices in different parts of the world.

In Part One we looked at speed limiter mandates in other countries. In this part, we review research and results in many of the more than 30 countries with speed limiters and what the future may hold there and elsewhere.


In 2006, the Canadian Trucking Alliance called on the Canadian federal and provincial governments to mandate speed limiters on all heavy trucks at no more than 65 mph (105 kilometers per hour, kph). While that industry proposal has not been adopted (outside of the pre-existing Ontario and Quebec requirements), it did generate substantial research by Transport Canada.

The Transport Canada research included reviews of other countries with speed limiter mandates, and as of 2008 found that:

  • 60% of all trucks in North America already had speed control devices, with 77% of trucks in large motor carrier fleets so equipped.
  • Fleets voluntarily adopted speed controls largely for fuel savings, and research calculations found those savings to be significant.
  • Environmental benefits were also substantial.
  • Most truck drivers, whether they like speed limiters or not, accept them as a fact of life.
  • Safety gains were positive but mostly anecdotal.
  • There was no indication that speed limiters had caused an accident, such as a rear-end collision of a speed-limited truck.

On the other hand, countries with mandated speed limiters reported tampering as a significant problem. A lack of training hindered compliance and enforcement efforts, made more challenging because tire-rolling radius and rear axle gear ratio affect engine control module (ECM) calculations of an accurate top speed. The research discovered compliance and enforcement were also affected by the continual updates in manufacturers’ proprietary ECM software, outpacing adjustments in law enforcement’s ECM reading tools.


Similar to most countries, Australian speed limiters work with a truck’s ECM. Unlike other countries, Australian enforcement utilizes the manufacturers’ own equipment to read ECM settings, preventing any lag behind ECM updates.

The number of heavy vehicles involved in accidents decreased after Australia implemented speed limiter legislation. The difficulty, however, is determining to what extent speed limiters, as opposed to infrastructure and other safety improvements, contributed to the decrease.

United Kingdom

UK officials report a 26% decrease in heavy truck accidents since introducing speed limiters. On the other hand, the large numbers of speed-limited trucks, relegated to the inside lane in the UK, can make it difficult for other vehicle traffic to access on- and off-ramps. And UK truck (“lorry”) drivers, accustomed to speed-limiting technology, report a tendency to “disassociate from the vehicle” – forgetting to drive — during long periods of operation.

European Commission and the Future of Speed Limiters

Beginning in 2022, all new cars sold in the 27 countries which follow European Commission recommendations will be required to install  “intelligent speed assistance” (ISA), or “intelligent speed adaptation.” ISA uses GPS and street sign detection to automatically adjust vehicle speed to the current legal limit in that location.

ISA sends visual and audible alerts to the car drivers when they exceed legal speed limits. Under the technical requirements set by the EC, motorists can override the ISA by stepping hard on the car accelerator or by simply disabling the device. India also mandated a similar system on cars several years ago, but that version cannot be turned off, so the audible warnings continue.

Other highway safety researchers recommend using communication lines embedded in the roadway or radio frequency communicators at roadside to trigger speed limit changes in vehicles equipped to receive those messages.

As for ISA in the United States, the National Transportation Safety Board identified this type of software as the basis for its recommendation that all trucks be held to local speed limits, not just to the maximum overall speed set on a speed limiter.

Regardless of the technology adopted, truck drivers and motorists must remain alert. Traffic, weather, and road conditions often dictate driving slower than the legal speed limit. And when considering the future of truck speed limiters in the US, a close eye should be kept on the advancement of ISA in European Commission countries.


This blog is published as a public service of PrePass®, the most reliable and technologically advanced weigh station bypass and electronic trucking toll payment platform in North America. PrePass also includes INFORM™ Safety and Tolling software for improving truck safety scores and lowering toll costs. Visit the PrePass website and learn more.