Tire Case Study

Case Synopsis: A commercial vehicle operator was fatally injured while operating a fully loaded tri-axle dump truck on a mountainous road. The truck was loaded with asphalt and was enroute to deliver the load to a waiting blacktop resurfacing crew. Before reaching his destination the operator negotiated several steep down-grades each requiring special care in braking and maintaining safe vehicle speed. The delivery zone was located on a steep incline. Upon his arrival, the operator attempted to stop but soon realized his brakes were not operating properly. Rather than stopping, the truck began to roll rearward back down the incline resulting in loss of control.

While negotiating the hills during his approach to the delivery zone, the operator necessarily engaged his brakes to maintain speed. However, whether due to poorly maintained brakes, improper speed control technique, or a combination of both, the brakes became overheated resulting in the phenomenon of brake fade.

Engineering Analysis: Drum-style brakes, and thus most commercial truck brakes, are particularly prone to brake fade. Brake fade results when the amount of kinetic (motion) energy applied to the braking system exceeds the system’s heat transfer capabilities. Brake fade can occur in even the best maintained system but poorly maintained systems are particularly at risk.

The available evidence in this case established the cause of the incident was consistent with improper speed maintenance techniques as well as poor vehicle maintenance.

Result: Case settled prior to trial.