IIHS: All top trailer manufacturers have sufficient underride protection

October 12, 2018

Tyson Fisher


As Congress is mulling over the topic of trailer underride guards, the Insurance Institute for Highway Safety has recently found that trailer manufacturers are doing a good job with rear underride guards. IIHS gave all eight of the largest North American trailer manufacturers its ToughGuard award for their rear underride guards.

According to an IIHS press release, the eight manufacturers are making rear underride guards capable of preventing deadly underrides in a range of scenarios. Those manufacturers:

  • Great Dane.
  • Hyundai Translead.
  • Manac.
  • Stoughton Trailers.
  • Strick Trailers.
  • Utility Trailer Manufacturing Co.
  • Vanguard National Trailer Corp.
  • Wabash National Corp.

Trailers that qualify for the ToughGuard award have rear guards that prevent underride of a midsize car in three test modes: full-width, 50 percent overlap and 30 percent overlap. In each configuration, a typical midsize car travels at 35 mph toward the back of a parked semitrailer.

In the full-width test, which all trailers were able to pass in the initial round of testing, the car strikes the center of the guard head-on. In the 50 percent overlap, which all but one trailer passed initially, half of the car’s front end strikes the guard. In the 30 percent overlap, the toughest evaluation, 30 percent of the car’s front strikes the corner of the trailer.

Manac was the only manufacturer that passed the 30 percent overlap test during the first round of testing. All the other companies made updates. By the time IIHS announced the ToughGuard award last year, five of the eight guards met the criteria.

According to IIHS, U.S. federal safety standards fail to prevent underride guards from buckling or breaking off in a crash. Canadian regulations, which are more stringent than U.S. regulations, also fail to prevent these safety precautions. After testing conducted by IIHS, some manufacturers have improved their guards that went beyond what the regulations call for.

“We’re pleased that all the major manufacturers responded positively to our underride tests,” said David Zuby, IIHS chief research officer, in a statement. “By improving their guards, these companies have demonstrated a commitment to the safety of passenger vehicle occupants who share the road with their trailers.”

IIHS’ report comes out during a time when both the House (HR4622) and Senate (S2219) have pending bills that would require the installation of front, rear and side underride guards on all trailers, semitrailers and single-unit trucks.

Called the Stop Underrides Act of 2017, both bills were introduced on Dec. 12, 2017. HR4622 was referred to the Subcommittee on Highways and Transit on Dec. 13, where it has been sitting in limbo ever since. No action has been taken on S2219 since its introduction.

In January, the Owner-Operator Independent Drivers Association penned a letter to the Senate opposing the bill. In the letter, OOIDA informed the senators that such a mandate would force truckers to “install costly devices that have no proven record of enhancing safety.”

“In fact, the mandates you’re promoting may actually increase the number of crashes on American highways, while simultaneously worsening their severity,” said OOIDA President Todd Spencer. “Your legislation also creates serious economic hardships and operational challenges for small trucking businesses, which comprise 96 percent of U.S. motor carriers.”


Tyson Fisher joined Land Line Magazine in March 2014. An award-winning journalist and tireless researcher, his news reports, features and blogs bring depth to our editorial content, backed with solid detail. Tyson is a lifelong Kansas Citian.