Lug Nut Damage Analysis

Lug Nut Expert Witness


Robert T. Lynch, P.E., Principal Collision Reconstruction Engineer
Often in lane change collisions involving commercial vehicles on a highway, the exposed lug nuts from a steer tire on the commercial vehicle will create obvious damage to the door(s) of a passenger vehicle, with little to no damage to the truck itself. The lug nuts will dig into the side of the vehicle and create a circular swirl pattern from the rotating wheel which is imprinted onto the doors and/or panels while the vehicles are in contact with each other.
Based on the characteristics of the swirl pattern, the collision reconstruction engineer can generally evaluate which vehicle was traveling faster when the contact was made. The Principal-Direction-of-Force (PDOF) can be determined, along with which vehicle was overtaking the other, and which vehicle was executing a lane change. Also, testing has been conducted to replicate the damage to the side of a passenger vehicle when it comes in contact with a steer wheel of a commercial vehicle at highway speeds. Utilizing the applicable test data, the collision reconstruction engineer establishes the severity of the contact by quantifying the forces, accelerations, and change in velocity that the passenger vehicle experienced during the contact. If the specific severity cannot be established from the data, often a maximum or minimum value can be ascertained to assist with the analysis.
Once the severity is established, the values can then be shared with the biomechanical/biomedical expert to evaluate the injuries.
Robert T. Lynch, P.E., Principal Collision Reconstruction Engineer with DJS Associates, Inc., can be reached via email at or via phone at 215-659-2010.

Categories: Uncategorized

Tags: Collision Reconstruction | Robert T. Lynch


Have A Question About This Article or Want to Contact the Expert?

Request An Expert

Fill out the form below so we may refer an expert

Do you have a question for us? We’re here to help!

James Schmidt Expert Spotlight