Model crash frequency at highway-railroad grade crossings using negative binomial regression

Shou Ren Hu, Chin-Shang Li, Chi Kang Lee

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Despite the fact that traffic collisions at highway-railroad grade crossings (HRGXs) are rare events, the impact of HRGX crashes is nevertheless more severe than highway crashes. Empirical studies show that traffic collisions at HRGXs are mainly attributed to railway-related and/or highway-related characteristics, particularly drivers' abnormal behavior, driving around, or through an HRGX. These factors have different effects on crash likelihood (i.e., the number of traffic collisions or crash frequency) at an HRGX. To explore the causal relationship between crash frequency and the factors related to railroad and highway systems, we used a negative binomial regression model to identify the factors that are statistically significantly associated with traffic collisions at HRGXs, and conducted relevant sensitivity analyses to investigate the marginal effect of daily highway traffic on changes in crash frequency. The empirical study shows that the number of daily trains, the number of tracks, highway separation, annual averaged daily traffic (AADT), and crossing length had statistically significant effects on the mean number of traffic collisions (all p-values < 0.0487). Further, the marginal effect of the AADT on the change of crash frequency indicates that crash likelihood monotonically increases with the increase of AADT.

Original languageEnglish (US)
Pages (from-to)841-852
Number of pages12
JournalJournal of the Chinese Institute of Engineers, Transactions of the Chinese Institute of Engineers,Series A/Chung-kuo Kung Ch'eng Hsuch K'an
Issue number7
StatePublished - Oct 2012


  • Crash frequency
  • Highway-railroad grade crossing
  • Marginal effect
  • Negative binomial regression

ASJC Scopus subject areas

  • Engineering(all)


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