The backbone of most supply chains is the trucking business. This highly competitive industry requires that loads be delivered on-time and in an economic manner. A major logistics company has found that accidents causing driver injury are inhibiting their ability to meet both requirements. Non-fatal injuries for truck drivers are 7 times the national average, and 30% of these are from falls, slips, and trips. Specifically, an ongoing problem is drivers slipping and falling when entering and exiting tractor cabs. Better entry-and-exit hardware and procedures need to be developed and implemented.
To contribute to solving this problem, Oregon State University (OSU) was contacted by a major truck manufacturer to develop supplemental hardware and procedures. The project was pursued through OSU’s Prototype Development Lab (PDL). The work performed consisted of (i) a background investigation to determine accident root causes, (ii) development of alternative design solutions, (iii) selection of a preferred design solution through consultation with all stakeholders, (iv) development of the preferred solution consisting of a hardware prototype and associated procedures, and (v) evaluation and revision of the solution based on user feedback.
The background investigation was performed as follows. To determine the causes, the company’s safety procedures and incident reports were reviewed. From this information, a driver survey was developed. This provided a data set from which an industrial engineering analysis was performed. The root causes of the accidents were clearly identified. These are: slipping on steps, not following the “three points of contact” rule, and the handles not proving appropriate grip. Slipping and not having enough grip is a design problem with the driver hardware aids for transiting to and from the cab. Not following procedure is a behavioral problem. There is a well-engineered procedure in place for transiting between the cab and the ground. However, drivers often circumvent this solution leading to accidents.
Alternative design solutions were created to address both the shortcomings of the current hardware and the current circumventable procedures. This consisted of four mechanical-device concepts that could be retrofitted to existing cabs that improved grip and prevented the drivers from exiting the cab in a manner contrary to the established procedures.
The design selection was performed based on feedback from project stakeholders. Ultimately, the effectiveness of the solutions was determined by driver response, so a second survey was made to gauge driver feedback. This was used to present the options to the trucking manufacturer and logistics company. A single design solution was chosen.
The solution was an additional mechanical handle retrofitted to the cab. This handle swings out from the driver’s foot-well and impedes entering and exiting the cab in an improper manner. It also provides a more accessible, more rigid point of contact.
To evaluate this solution, a prototype polyethylene handle was made to determine proper placement and function in a truck cab. From this, the handle was revised, and a functional prototype was created. This allowed testing and an ergonomic study to be performed. A final design was then created. This was forwarded to the truck manufacturer for final development and mass production.