Truck Crash Reference

Underride crashes

Last updated . Sources checked

Contents
  1. Guard and vehicle standards
  2. Protection on vehicles in service
  3. Preserving the equipment question
  4. Related entries
  5. References
Underride crashes
Rear guard standard49 CFR 571.223[1]
Covered trailer protection49 CFR 571.224; applicability and exclusions matter[2]

Underride occurs when a smaller vehicle passes beneath part of a larger vehicle in a collision. Federal rear-impact protection provisions address particular vehicle classes and equipment. A rear guard is not a universal barrier against every impact direction or crash severity, and rear protection rules must not be described as a general side-guard requirement.[3][1][2]

See: FMCSA and federal trucking rules

Guard and vehicle standards

Federal Motor Vehicle Safety Standard No. 223 sets requirements for rear-impact guards. Standard No. 224 addresses rear-impact protection for covered trailers and semitrailers, including installation. Both standards have applicability provisions and exclusions. A vehicle investigation should establish the trailer type and manufacture date before deciding which version and requirements apply; a standard number alone does not answer those questions.[1][2]

Protection on vehicles in service

Section 393.86 addresses rear-impact guards and rear-end protection for commercial vehicles in service. It distinguishes covered newer trailers and semitrailers from other vehicles and lists exceptions. The rule is not a promise that a guard will prevent injury in every collision. Whether equipment complied and how it performed in the particular impact are related but separate questions.[3]

Preserving the equipment question

The federal provisions make guard dimensions, attachment and strength relevant to the applicable standard. Photographs of the rear assembly and identification of the trailer are therefore useful starting points, but a condition assessment may require examination of the guard and its mountings. Side impacts should be analysed on their own facts rather than treated as violations of a rear-impact standard merely because underride occurred.[3][1][2]

References

  1. abcd 49 CFR 571.223: Standard No. 223; rear impact guards. Electronic Code of Federal Regulations, Office of the Federal Register and GPO. https://www.ecfr.gov/current/title-49/section-571.223. official. Checked . Source record
  2. abcd 49 CFR 571.224: Standard No. 224; rear impact protection. Electronic Code of Federal Regulations, Office of the Federal Register and GPO. https://www.ecfr.gov/current/title-49/section-571.224. official. Checked . Source record
  3. abc 49 CFR 393.86: Rear impact guards and rear end protection. Electronic Code of Federal Regulations, Office of the Federal Register and GPO. https://www.ecfr.gov/current/title-49/section-393.86. official. Checked . Source record