System precursors to signals passed at danger (SPADs): An exploratory comparison of SPAD history and rail environment

Despite the focus on signal passed at danger (SPAD) incidents as a product of interactions in complex rail systems, few studies have identified salient precursors that could lead to SPADs. This descriptive study undertook an exploratory analysis of data collected from an international survey (Australia & New Zealand) to derive preliminary insight into the extent to which different systems factors negatively affect rail driving from a driver perspective, and how these factors compare between SPAD history and type of rail environment(freight; passenger). Rail drivers (N=751) completed an online survey and rated the extent to which various precursors from the RSSB 10-Incident factor scheme negatively impacted their driving. Five groupings were selected for exploratory analysis(verbal communications; fatigue, health and well being; infrastructure, vehicles, equipment, and clothing; workload and resourcing; team working and leadership). ANCOVA analyses were undertaken on SPAD history (controlling for years of driving experience)and ANOVA analyses were undertaken for rail environment. Significant differences between passenger and freight rail environments were found within all five categories. Significant differences between drivers with SPAD history were also found for factors related to fatigue, health and well being, as well as infrastructure, vehicles, equipment, and clothing.Focusing on SPAD prevention addresses concerns linked with the rising complexities of rail, intensification of services, and increased automation. The findings of this exploratory study, while preliminary, hint at the beginnings of a systems and cognitive model to predict SPAD-risk. Further research and analyses of these data will go some way towards filling the research gap on SPAD precursors.