Correlation Between Crash Severity and Embankment Geometry

Kevin D. Schrum, Francisco Daniel Benicio De Albuquerque, Dean L. Sicking, Ronald K. Falle, John D. Reid

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


The severity of a roadside feature is often based on survey responses and has tended to emphasize extreme crash events, thereby overestimating the average severity of a particular feature. In this study, severity was related to embankment geometry by examining real-world accident data over a 7-year period. This was done by correlating the number of severe and fatal accidents to the exposure of particular slope geometries. Slope geometry was described by slope steepness and fill height, and its exposure was described by traffic volume and total unshielded mileage. Severity was adjusted for posted speed limits as well. The Roadside Safety Analysis Program (RSAP) was calibrated such that the distribution of severe injury and fatal accidents accurately reflected real-world data. Using this calibrated version of RSAP, the new severity indexes were studied and equations were created to correlate severity index to functional class, fill height, slope steepness, and posted speed limit. The local highway classification provided the highest severity, and the default severity used in RSAP was increased to accommodate this finding. Freeways, rural arterials, and urban arterials experienced reduced severity indexes relative to default values used in RSAP. © 2014

Original languageEnglish
Pages (from-to)321-334
Number of pages14
JournalJournal of Transportation Safety and Security
Issue number4
Publication statusPublished - Oct 2014
Externally publishedYes


  • RSAP
  • benefit-cost analysis
  • embankments
  • fatal accidents
  • foreslopes
  • roadside
  • roadside safety
  • severe accidents
  • severity index

ASJC Scopus subject areas

  • Transportation
  • Safety Research


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