Truck 5th Wheel Evaluation and Accident Causation Analysis

5th Wheel Jaws Exhibiting Corrosion
5th Wheel Jaw Showing Signs of Repeated Impact


Keywords: Accident Causation; 5th Wheel not Locked

O’Donnell Consulting Engineers, Inc. was retained to investigate and determine the cause of the separation of a trailer from its tractor.

In January of 2014 in Clermont County, a trailer travelling eastbound decoupled from its tractor, crossed the centerline and hit a pickup truck head-on, fatally injuring its driver.

We concluded that it was not possible for the 5th wheel’s jaw to become unhooked while travelling if it was properly hooked up and initially locked in place. The excessively thick and dirty grease interfered and did not allow the jaw to be fully inserted into the lock.

It was determined that one of the major causes of the fifth-wheel failure was due to lack of maintenance and lubrication. The condition of the fifth wheel on the day of the accident made hooking up and locking the trailer to the truck unreasonably difficult, increasing the chance of a partial hookup.


O’Donnell Consulting Performs Forensic/ Expert Witness Services on Trucking Accidents – Including Those involving 5th Wheels.

(412) 835-5007

Scroll to Top