Phase 2 - Existing Systems Analysis

Phase 2 of the research programme involved generating systems models of rail level crossings, using the data collected during Phase 1. Although the data collection activities alone provided a number of key findings and insights into specific aspects of user behaviour, it was not until the data were synthesised through a systems thinking lens that a deeper understanding could be gained. The formative analysis provided through CWA outputs yielded pivotal information around the system constraints that affect the functioning of rail level crossing systems and activity conducted within them.

In addition to analysing the data collected in Phase 1, we engaged with subject-matter experts from the rail and road industries to validate the Work Domain Analysis models generated for rail level crossings. This was an important step as the Work Domain Analysis underpins the latter phases of CWA. It also provided an opportunity to engage with stakeholders and familiarise them with systems thinking ideas and methods.

In addition to CWA, Hierarchical Task Analysis (HTA) and the Systematic Human Error Reduction and Prediction Approach (SHERPA) were applied using an explicitly systems-focussed perspective. Instead of a traditional HTA, which focusses on the goals of individuals (workers, operators or users), this HTA considered all system actors (both humans and technologies) and provided a decomposition of the system goals, sub-goals, operations and plans. In this way, the SHERPA taxonomy could be used to identify potential errors or failures across the entire system, rather than only those associated with human behaviour. Conducting HTA and SHERPA presented an interesting comparison to the CWA and produced a normative standard against which designs could later be evaluated.

See Chapter 2 for an overview of CWA, HTA and SHERPA methods, and Chapter 5 for more information about their application in this research.