Engineering Design Analysis: Lessons from a Dump Trailer Accident Investigation

Article By Rob Irion

In product liability cases, understanding why an accident occurred is often the key to determining who is liable. Recently, Alpine Engineering & Design was asked to conduct an engineering design analysis and accident investigation on a dump trailer involved in a hand injury incident. The goal was to determine whether the design of the trailer played a role in the accident and, if so, how the hazard could have been prevented.

Background

The incident involved a bumper pull dump trailer, generic example shown below, that was being used to haul and unload soil. The trailer’s total weight rating (combined weight of trailer and payload, GVWR) was roughly 10,000 lb. The dump trailer included common hydraulic systems to lift and lower the bed for unloading.
During operation, the operator’s hand became caught between the trailer bed and the frame, resulting in the loss of his thumb and finger. This type of hazard is known in the engineering and safety industry as a “pinch point.”
Our trailer design analysis focused on the design of the trailer, specifically, whether foreseeable use could expose a person to serious injury, and whether safer design alternatives existed at the time of manufacture.

Engineering Design Analysis Findings

Upon inspection, Alpine Engineering & Design noted several safety concerns:

Unsafe control placement: The control handle used to raise and lower the dump bed was located close to the pinch point where the operator’s hand could easily be trapped. The handle’s position required the user to lean over the trailer frame, an ergonomically awkward and hazardous position.

High crushing forces: Engineering analysis revealed that even an empty bed could generate around 400 pounds of crushing force at the pinch point. When loaded, the force could easily exceed 1,400 pounds, enough to cause catastrophic injury.

Worn or missing warning labels: The trailer’s safety decals had deteriorated to the point of being unreadable. According to ANSI standards, product safety labels must remain legible for the expected life of the equipment.

In short, the trailer’s configuration allowed an operator to be within inches of a serious hazard during normal use.

Hazard and Safety Analysis

Using established safety analysis standards (such as ANSI B11.TR3), Alpine Engineering & Design conducted a risk assessment. The hazard was classified as both catastrophic (due to the severity of potential injury) and likely (due to frequent operator exposure and lack of protective measures). Under accepted engineering principles, such a risk level is not tolerable and must be reduced through design changes or safety controls.

Safer Design Alternatives for Equipment Safety

Several safer design options were identified that were both technologically feasible and cost-effective:

  1. Relocating the controls away from the pinch point to a safer area
  2. Using longer or tethered control handles to allow the operator to stand clear of moving parts
  3. Adding protective guards or shields to physically prevent contact with the hazard area
  4. Improving labels and warnings to ensure long-term visibility and clear hazard communication

All of these changes could have been implemented for minimal cost compared to the price of a dump trailer, and would have significantly reduced the risk of injury. Real-world testing and validation of these safety features ensures they can withstand the extreme forces involved in trailer operation.

Key Takeaway

The main lesson from this accident investigation is that product safety must be designed in from the start. A simple design review, using standard risk assessment methods, would have identified the risk and prevented the injury.

From a legal standpoint, this case highlights how engineering design analysis can demonstrate whether a product met reasonable safety expectations at the time it was made. It also shows that safer alternative designs often exist, and that ignoring them can expose users to unnecessary risk.

Frequently Asked Questions About Engineering Design Analysis

What is engineering design analysis?

Engineering design analysis is a systematic evaluation process that examines mechanical systems, products, or equipment to assess their safety, performance, and compliance with industry standards. It involves reviewing design specifications, conducting risk assessments, analyzing structural integrity, and identifying potential hazards before they result in accidents or failures.

When is engineering design analysis required?

Engineering design analysis is typically required during product development, after accidents or failures occur, in product liability cases, and when modifying existing equipment. It’s also used for compliance verification with OSHA, ANSI, ASTM, and other regulatory standards, particularly for trailers and heavy equipment.

What is a pinch point hazard?

A pinch point hazard occurs when two objects move together and the space between them decreases, creating a risk of crushing or catching body parts. In trailers and heavy equipment, common pinch points include areas between moving beds and frames, between hydraulic components, and near articulating joints. These hazards require guards, proper control placement, or clear warnings.

How does engineering design analysis prevent accidents?

Engineering design analysis prevents accidents by identifying hazards early in the design phase. Through systematic safety analysis, engineers can evaluate risk levels, test for failure modes, and recommend design modifications such as protective guards, relocated controls, or enhanced warnings. This proactive approach eliminates hazards before they cause injuries.

What standards are used in trailer safety analysis?

Trailer safety analysis commonly references standards from DOT (Depoartment of Transportation), NATM (National Association of Trailer Manufactuers), ANSI (American National Standards Institute), SAE International, OSHA (Occupational Safety and Health Administration), and ASTM International. Specific standards like ANSI B11.TR3 provide guidelines for risk assessment and machinery safety that apply to trailer equipment and hydraulic systems.

What role does engineering design analysis play in legal cases?

In product liability and personal injury cases, engineering design analysis provides technical evidence about whether a product met reasonable safety standards at the time it was made.Engineering expert witnesses use design analysis to evaluate if safer alternatives existed, if proper warnings were provided, and if the design followed industry best practices.

About Alpine Engineering & Design

Alpine Engineering & Design is an engineering company that specializes in trailer design engineering services and equipment safety analysis. Our engineers evaluate mechanical systems and equipment to determine causes of failure, assess safety compliance, and identify practical design improvements. Alpine Engineering also provides unbiased trailer expert witness testimony in legal disputes involving product liability and accident investigation.