More than meets the eye: Using cognitive work analysis to identify design requirements for future rail level crossing systems.

An increasing intensity of operations means that the longstanding safety issue of rail level crossings is likely to become worse in the transport systems of the future. It has been suggested that the failure to prevent collisions may be, in part, due to a lack of systems thinking during design, crash analysis, and countermeasure development. This paper presents a systems analysis of current active rail level crossing systems in Victoria, Australia that was undertaken to identify design requirements to improve safety in future rail level crossing environments. Cognitive work analysis was used to analyse rail level crossing systems using data derived from a range of activities. Overall the analysis identified a range of instances where modification or redesign in line with systems thinking could potentially improve behaviour and safety. A notable finding is that there are opportunities for redesign outside of the physical rail level crossing infrastructure, including improved data systems, in-vehicle warnings and modifications to design processes, standards and guidelines. The implications for future rail level crossing systems are discussed.

Validating the strategies analysis diagram: assessing the reliability and validity of a formative method.

The Strategies Analysis Diagram (SAD) is a recently developed method to model the range of possible strategies available for activities in complex sociotechnical systems. Previous applications of the new method have shown that it can effectively identify a comprehensive range of strategies available to humans performing activity within a particular system. A recurring criticism of Ergonomics methods is however, that substantive evidence regarding their performance is lacking. For a method to be widely used by other practitioners such evaluations are necessary. This article presents an evaluation of criterion-referenced validity and test-retest reliability of the SAD method when used by novice analysts. The findings show that individual analyst performance was average. However, pooling the individual analyst outputs into a group model increased the reliability and validity of the method. It is concluded that the SAD method's reliability and validity can be assured through the use of a structured process in which analysts first construct an individual model, followed by either another analyst pooling the individual results or a group process pooling individual models into an agreed group model.

Using cognitive work analysis and the strategies analysis diagram to understand variability in road user behaviour at intersections.

In this article, an application of cognitive work analysis (CWA), using the strategies analysis diagram (SAD) method, to model performance variability in road transport, is presented. Specifically, the method was used to describe performance variability across four road user groups (drivers, cyclists, motorcyclists and pedestrians) when turning right at an urban signalised intersection. The analysis demonstrated that the method was able to identify a comprehensive range of strategies that road users can potentially use while turning right at an intersection, thereby describing a range of performance variability within intersection systems. Furthermore, the method identified constraints, disturbances, changes in circumstances and other influences on road user performance variability. It is concluded that the CWA/SAD approach was able to describe both the different ways in which activities can be executed and disturbances, situations and constraints that create performance variability. The implications of these findings for road design and intersection safety are discussed along with the benefits and drawbacks of the methodology used. PRACTITIONER SUMMARY: Recently, the strategies analysis diagram was proposed as a method to support the cognitive work analysis framework in modelling performance variability. This article evaluated this method within a complex sociotechnical system, namely road transport. The application provided insight into performance variability across road user groups when turning right at intersections.

Distraction-induced driving error: an on-road examination of the errors made by distracted and undistracted drivers.

This study explored the nature of errors made by drivers when distracted versus not distracted. Participants drove an instrumented vehicle around an urban test route both while distracted (performing a visual detection task) and while not distracted. Two in-vehicle observers recorded the driving errors made, and a range of other data were collected, including driver verbal protocols, forward, cockpit and driver video, and vehicle data (speed, braking, steering wheel angle, etc.). Classification of the errors revealed that drivers were significantly more likely to make errors when distracted; although driving errors were prevalent even when not distracted. Interestingly, the nature of the errors made when distracted did not differ substantially from those made when not distracted, suggesting that, rather than making different types of errors, distracted drivers simply make a greater number of the same error types they make when not distracted. Avenues for broadening our understanding of the relationship between distraction and driving errors are discussed along with the advantages of using a multi-method framework for studying driver behaviour.