The case of the crooked clock and the distracted driver : an assessment of key contributors to SPAD-risk for passenger rail operations

Signal passed at danger (SPAD) events continue to impact safety-risk on rail networks, despite theintroduction of novel technologies aimed at addressing the cause and effect. This paper presents datafrom a study that set out to explore the key contributors to SPAD-risk. Focus groups were conductedwith train drivers from 8 urban passenger rail organisations across Australia and New Zealand using agenerative forward scenario simulation task to identify the specific risks and strategies being used toameliorate them. Distraction and inattention scenarios were most prevalent. A thematic analysis ofthese data found that time pressure and controller interactions increased the likelihood of a SPADoutcome, and this risk was intensified when the factors converged. The two factors were intrinsicallytask-related and associated with disconnects between service delivery and driver-signal dynamicswhere attention was not so much being diverted as ‘subverted’ by workgroup norms. The mosteffective strategy used to ameliorate these risks was task prioritisation. A conceptual model illustratingthe relationship between these risk factors and how inattention gave rise to distraction is given. Thisstudy illustrates the problems with self-regulation that may manifest from contributing factors that arealso work norms, and goes someway to unravelling the mystery behind SPADs that may be classifiedas ‘driver misjudged’ in metropolitan rail operations.