FMCSA’s speed limiters: Unsafe at any speed?

Large sector of trucking wants government’s hands off engines despite concerns from safety advocates

Trucks and cars on interstate.

Truck and automobile traffic mix on Interstate 5 near Port of Tacoma in 2016 (Photo: Ted S. Warren/AP)

Plans by federal regulators to issue a proposed rule requiring speed limiters on truck engines is getting pushback by a significant portion of the trucking sector.

The Federal Motor Carrier Safety Administration’s April notice seeking comment on the plan, which the agency aims to issue as a proposed rule for public comment in 2023, generated more than 15,000 responses. Most came from independent owner-operators and small trucking companies, which account for the majority of FMCSA’s regulated carriers. And most were adamantly against it.

“I lease my trucks to a company that requires us to limit our speed to 65 mph,” wrote the owner of IAB Trucking. “I feel it has made my drivers more unsafe, as they get caught up in packs of drivers now. They are unable to maneuver when necessary. And I think automobile drivers are even angrier around trucks that have their speed limited. Please, do not require this.”

IAB Trucking’s sentiment was typical and was echoed among a large sampling of responses: Roads are less safe when trucks are unable to adjust their speed to surrounding traffic.


Benefits underscored

FMCSA’s planned petition will be in the form of a supplement to a notice of proposed rulemaking (NPRM) that was issued jointly in 2016 with the National Highway Traffic Safety Administration. It will propose that trucks weighing over 26,000 pounds that are equipped with an electronic engine speed governor be required to limit the truck’s speed to a rate to be determined by the rulemaking and maintain the speed setting for the life of the vehicle.

The American Trucking Associations, which developed a speed governing policy for commercial trucks in 2007, initially supported a fixed maximum speed of 65 mph for all Class 7 and 8 trucks with electronic speed governors manufactured after 1992.

ATA has since revised its policy to take into account the development of safety technology aimed at allowing trucks to travel faster and safer. For Class 7 and 8 trucks manufactured after 1992 equipped with automatic emergency braking (AEB) and adaptive cruise control, ATA supports setting speed governors to a maximum speed of 70 mph, according to comments filed at FMCSA.

The Truckload Carriers Association and Road Safe America, a nonprofit “with a mission to reduce the number of crashes between trucks and passenger cars,” both support ATA’s stance. Providing the option of a maximum speed of 70 mph for trucks using AEB and adaptive cruise control “would give existing fleets an incentive to purchase and use these amazing safety technologies,” wrote Road Safe America’s Steve Owings.


Advocates for Highway and Auto Safety also supports speed limiters — but it wants the maximum speed set to 60 mph. 

The safety group cited “incontrovertible” safety benefits highlighted in the FMCSA’s 2016 NPRM, where the agency noted that crashes involving heavy vehicles traveling faster are more deadly than those involving trucks traveling at lower speeds. 

“The 2016 NPRM estimates that setting the device at 60 mph has the potential to save almost 500 lives and prevent nearly 11,000 injuries annually,” commented Advocates President Catherine Chase. “By comparison, the NPRM clearly states that setting the speed at 65 or 68 mph will result in far less lives saved and injuries prevented.”

The Insurance Institute for Highway Safety (IIHS) also considers speed limiters a needed safety requirement, although it did not advocate for a particular speed setting for the devices.

“Although the use of speed limiters on large trucks has raised concerns about creating speed differentials between trucks and other vehicles, research has documented that trucks already travel significantly slower than passenger vehicles, including on roads with speed limits raised to among the highest in the nation,” IIHS stated.

Less safe, more delays?

The thousands of individual owner-operators commenting on the proposal who opposed requiring speed limiters on their trucks were backed by associations representing small businesses, in particular the Owner-Operator Independent Drivers Association.

Speed limitNumberPercent
25 mph or less1232.7%
30-35 mph3167.1%
40-45 mph63514.2%
50-55 mph1,49133.3%
60-65 mph89720%
70-75 mph86019.2%
80-85 mph240.5%
No statutory limit451.0%
Unknown882.0%
Total4,479100%
Fatal crashes involving large trucks, 2019 data
(Updated Oct. 2021). Source: FMCSA

In addition to unsafe speed differentials resulting if speed limits on certain roads have higher speed limits than those governed by the engine’s control unit, speed limiters take away a driver’s ability to avoid accidents and unsafe road conditions, according to OOIDA President and CEO Todd Spencer.

In addition, “speed limiters increase driver stress and make drivers more fatigued because they must operate longer hours in order to complete the work expected of them, and they must also operate at the maximum allowed speed for more of those hours,” Spencer said. “In a survey of our members, drivers that are required by their carriers to use speed limiters also report feeling pressure to ‘make up’ time on local roads when the posted speed limit is lower than the speed set on the truck.”


The Livestock Marketing Association, which represents more than 80% of local livestock auction markets, agreed that the use of speed limiters “ignores the very real safety hazard of speed differentials and fails to account for the safety impacts when a 60, 65 or 68 mph limit is applied to a [truck] while surrounding traffic are traveling speeds 10, 15 or even 20 mph faster. This difference in speeds will cause more dangerous conditions for the motoring public.”

Mandating slower truck speeds, he said, “will literally slow the movement of freight through the supply chain. At a time when businesses and families are having difficulties securing the supplies they need, this proposal would create additional challenges and delays.”

One commenter used FMCSA’s own data to counter research from safety and insurance groups used to support speed limiters (see table, above).

The commenter noted that according to FMCSA, highways with posted speed limits of 50-55 mph account for 33.3% of all fatal crashes and that highways with speed limits of 60-65 mph and 70-75 mph account for significantly fewer fatalities.

“What is more, this data shows that out of 4,479 fatal crashes only 1.0% (45 fatal crashes) occurred in areas with no statutory speed limit” and 97% occurred in areas with speed limits. “This evidence suggests on its face that fatal crashes are less likely, not more, as posted speed limits are increased or removed altogether.”

Click for more FreightWaves articles by John Gallagher.

Fatal crashes involving large trucks

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