Throwing good money after SPAD? Exploring the cost of signal passed at danger (SPAD) incidents to Australasian rail organisations

Anjum Naweed, Joshua Trigg, Steven Cloete, Phil Allan, Todd Bentley

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


This study sought direct estimates of incidence, preventative costs, and reactive costs associated with the occurrence of low risk (‘typical’) Signal Passed at Danger (SPAD) events in Australasian rail. In a cross-sectional multiple-case design, a descriptive questionnaire was sent to eight operators, and completed by managerial personnel with responsibility for SPAD-risk mitigation. Items addressed SPAD frequency, operator delays, and a range of preventative and reactive costs associated with low-severity (‘low-risk’) SPADs. Delay costs varied between cases, with each having different organisational size and network density. Preventative costs were mostly comprised of internal SPAD prevention team maintenance, participation in a collaborative SPAD Group, and resultant network modifications. Reactive costs were largely comprised of driver-related factors and in two cases, of higher low-risk investigation and regulatory costs. The ratio of preventative to reactive costs (P:R) varied widely, approaching equilibrium for two cases only—both participated in internal and external SPAD preventative team consultation. One freight organisation noted a large P:R imbalance due to very low preventative costs. Low-risk SPADs represent a host of substantial annual costs for each Australasian passenger- and freight-rail organisation. As this study gives preliminary estimates, these likely underestimate the full costs, as multiple other factors are yet to be accounted for. This study justifies the need for detailed analysis of SPAD-associated costs to contrast data from multiple rail organisations, and a clearer picture of how organisational expenses are allocated within SPAD prevention and reaction.

Original languageEnglish
Pages (from-to)157-164
Number of pages8
Publication statusPublished - Nov 2018
Externally publishedYes


  • Preventative costs
  • Rail safety
  • Reactive costs
  • Risk mitigation
  • Signal passed at danger


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