Open Cut » Health and Safety
The design process reflected the requirements of ISO 9241-210 Ergonomics of human-system interaction Part 210: Human-centred design for interactive systems. A multidisciplinary design team followed an iterative process that:
- commenced with a thorough understanding of users, tasks and environments;
- involved users throughout;
- and the resulting design was refined by user centred evaluation.
The activities undertaken broadly fall into four categories: understanding the context; specifying user requirements; producing design solutions; and evaluating these designs.
An understanding of the context of use for the system was developed over preceding years through activities of the Earth Moving Equipment Safety Round Table, including the definition of 24 surface mining vehicle interaction scenarios, and performance requirements for these scenarios, based on an understanding of Endsley's model of situation awareness. Additional understanding of the company specific context was obtained through Glencore's Vehicle Interaction Control Effectiveness project during which workshops were held at eleven surface coal mines.
A detailed set of functional requirements for a surface mining collision awareness system was developed that provided use cases describing scenarios from the perspective of the different users of the system including heavy equipment operators, light vehicle operators, supervisors and others. The functional requirements considered the 24 surface vehicle interaction scenarios previously identified, as well as 15 additional scenarios such as speeding or wet roads. An assessment of current technology was undertaken with reference to user-interface specifications developed from review of research evidence and relevant standards.
The design process included a series of workshops to define the user experience. These workshops included experienced users and subject-matter experts, Wabtec designers, and Glencore project team; as well as a Certified Professional Ergonomist. Animated “story-boards” were a crucial tool developed during the design process to allow the outcomes of the workshops to be effectively captured, communicated, and modified as required based on operator feedback.
The system design was evaluated through field assessments of 384 user and performance requirements across the 39 scenarios. Designers accompanied heavy equipment and light vehicle operators during staged scenarios to evaluate the functionality of both the collision awareness technology and the effectiveness of the interface in eliciting an appropriate responses across each scenario. In cab video footage was recorded during each test and the response of drivers to alerts and alarms was evaluated from the vehicle acceleration data. Drivers were also debriefed following each test. Few modifications were required to the interface design logic as a consequence of the field evaluations however several adjustments were made to the configurable system parameters. Feedback from operators post-implementation provided impetus for further modifications.
The data provided by the system have potential to provide considerable additional value such as promoting more efficient choreography of equipment movements to improved productivity and improve safety by reducing potential vehicle interactions.
The design process undertaken by Glencore/Wabtec provides a good example of a human-centred design process that reduces the risk of system failure by considering human capabilities and limitations, and involving users in the design process. The resulting system is consistent with current best practice human factors principles for interface design.