Cover Story
Speed limiters

By Greg Grisolano, associate editor

A diverse coalition of trucking groups, motorcoach associations, motorists, and even a state DOT are voicing their displeasure with a proposal to mandate speed limiters on vehicles weighing more than 26,000 pounds.

At press time, more than 5,600 comments had been filed at addressing a joint notice of proposed rulemaking by the National Highway Traffic Safety Administration and the Federal Motor Carrier Safety Administration to mandate speed limiters in heavy vehicles.

The majority of those opposed to a proposed mandate to speed limit vehicles weighing more than 26,000 pounds say the risks posed by increasing vehicle interactions via speed differentials outweigh any purported safety benefit of slowing large trucks and buses down.

The Owner-Operator Independent Drivers Association opposes a government mandate speed limiting trucks, pointing to research that contradicts the fed’s claimed "safety benefits" of speed limiters, as it would force a speed differential between heavy trucks and other vehicles using the highways. That would lead to more vehicle interactions, unsafe maneuvering and crashes, a study of speed differentials shows.

Many of the comments submitted by professional drivers and owner-operators echo the sentiments shared by Marek Kosarewicz, who says a proposed mandate would cause more problems than it would solve. Among the problems Kosarewicz cites in his comment is that speed limiters would not address the issue of trucks traveling faster than the posted speed in work zones or other areas where the speed limit is less than highway speed.

"One of the main issues I see with a mandate is that it will not prevent speeding in towns with lower speed limits and especially work zones; actually, it will become more common, putting workers at risk," Kosarewicz stated in his comments. "I lost count of how many trucks from the megafleets I have seen flying by me running against their governed speed and tailgating me when I’m driving the posted work zone speed limit."

The long-awaited notice of proposed rulemaking was first published on Sept. 7 with a 60-day comment period, but the agencies and the U.S. Department of Transportation agreed to tack on an additional 30 days to the comment period after receiving multiple requests from industry stakeholders. The agencies seek public comment on a variety of issues connected with speed limiters, including whether to set the speed at 60, 65 or 68 mph. The proposal claims that reducing the travel speed of large vehicles will lead to a reduction in the severity of crashes, thereby reducing the number of fatal and serious injuries and lessening property damage.

Bill De Witt, who identified himself as a commercial driver with more than 42 years of experience, commented that there is no way to ensure equal speed on all trucks, because of differences in tire wear and gearing. He also said his experience running in states with split speeds such as California and Oregon allowed him to see the risks of speed differentials firsthand.

"I have had cars pass me on the right and left shoulders as two trucks pass each other on a two lane interstate. It already blocks traffic when two fleet trucks with 65 mile-per-hour limiters pass each other," De Witt stated in his comments. "Having run in split-speed-limit states (i.e., California, Oregon, Washington) for years, I have seen firsthand the rear-end accidents and near misses as cars pass on the right to get around a slower vehicle."

The issue of tire wear and gearing ratios contributing to potentially inaccurate speedometer readings was also raised in comments filed by the Truck and Engine Manufacturers Association. In its comments filed Oct. 21, the group requested an additional 30-day extension of the comment period to research the impact of the issue further, noting that inaccuracies in the number of revolutions per mile for a particular tire would affect the accuracy of the vehicle speedometer.

The Michigan State Department of Transportation voiced its opposition to the mandate, citing a variety of issues, including the dangers of split speeds and the safety impact of speed differentials, as well as that the proposal would amount to "a federally-mandated national speed limit for trucks and buses… without regard for varying conditions and geography among the states," according to the comments filed by MDOT Director Kurt Steudle.

Other national groups who filed comments opposing the proposed mandate or expressing concerns with the current proposal include the National Motorists Association, the American Farm Bureau Federation, the National Groundwater Association, and the National Federation of Independent Business.

Many of the comments in favor of the proposal also voiced support for any mandate being extended to include retrofitting all heavy vehicles with speed limiters. Groups that filed comments in support of the mandate include the Insurance Institute for Highway Safety, the National Safety Council, and the National Transportation Safety Board.

NTSB also filed comments in support of the measure, but referred to the current proposal as an "interim step" toward an eventual requirement that all newly manufactured heavy vehicles be equipped with "advanced speed limiting technology" such as variable speed limiters and intelligent speed-adaption devices, which would address concerns that electronic engine control unit-based speed limiters do not prevent speeding in locations where the speed limit is lower than the governed speed or stop vehicles from exceeding the governed speed when traveling downhill.

All comments received by the deadline will be considered by the joint NHTSA and FMCSA team. Comments only need to be posted to one docket. More information about the Association’s opposition to the mandate can be found at