New Standards for ICC bars

The National Highway Traffic Safety Administration (NHTSA) has published new standards requiring rear impact guards (ICC bars) on new trailers to meet size location and performance criteria, and to be certified at the time of manufacture.

The ICC bar name derives from the Interstate Commerce Commission, an agency that once oversaw the transportation industry in the United States. It’s sometimes referred to as a rear impact guard (RIG), rear underride guard, a Mansfield bar or a DOT bumper.

While the new standards are effective for trailers built after January 1998, many trailer manufacturers have changed their designs, and the majority of semi-trailers on the road today have the newer stronger rear impact guards. Although the primary purpose of the new standard is to help reduce the chance of death or serious injury if an automobile collides with the rear end of a trailer (underride crash), conforming rear impact guards also provide distinct safety advantages for loading dock operations equipped with Dok-Lok® vehicle restraints.


Damage to rear impact guards is much less likely with the new, stronger design as trailers will be less likely to separate from the dock even if the truck driver ignores visual communication signals and attempts to pull out (early departure) when a vehicle restraint is engaged. Preliminary survey results indicate the new rear impact guards to be five to ten times less susceptible to damage than typical “old” designs. If damage does occur, the Federal Highway Vehicle Administration is likely to require repair of the guards, helping ensure their continued strength and integrity in protecting against unscheduled departure.


Fewer uncompliant rear impact guard designs will help reduce the incidence of difficult or ineffective trailer restraint engagement. Percentage of restrainable over-the-road trailers is likely to increase over the historic 95-98% rate.


Bumper requirements for trailers and semi-trailers call for specific measurements around impact guard width, guard height, guard rear surface and cross-sectional vertical height. Standard sizing across the board makes future-proof construction more attainable for older facilities looking to update.

  • How wide should the rear impact guard be? The outermost surfaces of the horizontal member of the guard must extend to within 100 mm (4 inches) of the side extremities of the vehicle. The outermost surface of the horizontal member shall not extend beyond the side extremity of the vehicle.
  • How high is a rear impact guard? The vertical distance between the bottom edge of the horizontal member of the guard and the ground shall not exceed 560 mm (22 inches) at any point across the full width of the member. Guards with rounded corners may curve upward within 255 mm (10 inches) of the longitudinal vertical planes that are tangent to the side extremities of the vehicle.
  • How close does the rear impact guard rear surface need to be? At any height 560 mm (22 inches) or more above the ground, the rearmost surface of the horizontal member of the guard must be within 305 mm (12 inches) of the rear extremity of the vehicle. This paragraph shall not be construed to prohibit the rear surface of the guard from extending beyond the rear extremity of the vehicle. Guards with rounded corners may curve forward within 255 mm (10 inches) of the side extremity.
  • How high should the rear impact guard’s cross-sectional part be? The horizontal member of each guard must have a cross sectional vertical height of at least 100 mm (3.94 inches) at any point across the guard width.

The updated standards help ensure trailer restraint systems will be more effective at your loading dock. If you’d like to be more effective, and stay on top of key safety standards in your industry, read “OSHA Warehouse Safety Standards You Need To Know.”

ICC Bar and RIG Compliant Vehicle Restraints

improving industrial safety, security and productivity worldwide THROUGH QUALITY AND INNOVATION