FMCSA denies request to correct underride review

The Insurance Institute for Highway Safety petitioned the Federal Motor Carrier Safety Administration to correct the agency’s review of side underride guards. In April, FMCSA denied the request.

On April 17, FMCSA posted its response letter to IIHS President David Harkey, who requested in December 2024 that the agency withdraw its own report and replace it with the Volpe Center’s analysis of how tractor-trailer side guards and skirts could reduce fatalities of pedestrians and cyclists.

“FMCSA has determined that no correction is necessary under the Information Quality Act,” the agency wrote.

FMCSA review and IIHS request

Underride crashes most commonly occur when a car slides underneath a tractor-trailer. Regulations already require rear underride guards, but truck safety groups have long advocated for a side underride guard mandate.

In May 2020, FMCSA published a review of how lateral protection devices on tractor-trailers are intended to reduce pedestrian and cyclist fatalities.

In that report, the agency suggested that lateral protection devices may be relevant to about 0.3% of all pedestrian fatalities and 1.4% of all cyclist fatalities in the U.S. each year. The review also revealed limited effectiveness rates for collisions between large trucks and vulnerable road users. It was estimated that lateral protection devices would mitigate serious injury for bicyclists between 3% and 9% of the time and 0% of the time for pedestrians.

IIHS criticized FMCSA for omitting a cost-benefit analysis from the Volpe Center, which estimated that side guards or skirts could prevent about 100 bicyclist and pedestrian deaths each year. The Insurance Institute called the DOT’s findings on the effectiveness of side underride guards “fundamentally flawed.”

“The Volpe Report only bolsters our beliefs,” IIHS wrote in December 2024. “Accordingly, we request that the FMCSA report be withdrawn and replaced with the Volpe report.”

FMCSA’s denial

The agency said that Volpe’s cost-benefit analysis was not included in its report because it was flawed.

“The cost-benefit analysis included in the Volpe report was flawed because it overestimated the target population without detailing the source of the estimate, overestimated the effectiveness of lateral protection devices in various crash scenarios and underestimated the cost of (lateral protection devices), installation and maintenance cost and additional fuel cost due to the added weight of (lateral protection devices),” the agency wrote.

Divisive issue

FMCSA’s rejection letter is the latest chapter in the divisive issue of whether side underride guards should be mandated.

In 2023, the National Highway Traffic Safety Administration issued an advance notice of proposed rulemaking that considered requiring side guards on trailers. Although safety groups have long advocated for the requirement, the preliminary research provided by NHTSA indicated that the annual cost of the mandate would be as much $1.2 billion, while saving fewer than 20 lives each year.

Congress launched the creation of an Advisory Committee on Underride Protection to provide recommendations on how to reduce the number of underride crashes. However, the committee was never able to find common ground.

In July 2024, the committee submitted a 410-page report that consists of recommendations from the majority of members and dissent from those in the minority.

The majority report called for a side underride guard mandate on all semitrailers and single-unit trucks. The minority report suggested that additional investigation is needed and that research should be conducted regarding potential unforeseen consequences resulting from a side underride mandate.

The committee, which was mandated by Congress, was created with a natural divide. Three of the committee’s original 16 members had family members who died in underride-related crashes. In addition, several of the members have long lobbied for a side underride guard mandate. Doug Smith, an OOIDA board member, was the only truck driver on the committee.

That divide often led to much of the meeting time being spent on procedural motions rather than generating a unified plan. At the February 2024 meeting, the committee argued over the definition of a consensus. The members representing safety groups argued that a simple majority would suffice as a consensus even though previous DOT committees have required thresholds of 75% or higher.

Inexplicably, the committee was then able to use a simple majority vote to determine that the committee would need only a simple majority to include something in its “consensus” recommendations to the DOT. Explaining it another way, it would be as if Congress failed to meet the two-thirds threshold needed to override a presidential veto and then used a simple majority vote to lower the veto threshold.

The fractured report prompted the Owner-Operator Independent Drivers Association to write a letter to lawmakers. The July 2024 letter called out the lack of a true consensus.

“NHTSA should not advance potential new underride standards until further research, analysis and testing is completed as directed in the bipartisan infrastructure law,” OOIDA wrote. “The only recommendations that garnered true consensus support among panel members generally involved enhancing research and reporting. As such, these are the only elements of the final report Congress and the U.S. DOT should take seriously.

“Over the course of these meetings, (the committee) failed to work in a collaborative and consensus fashion,” OOIDA wrote. “Safety advocacy representatives manipulated their numerical advantage in committee membership and approved a motion to define ‘consensus’ as a simple majority that minimized opposing viewpoints of other (committee) participants.” LL