Effects of heavy rainfall in different light conditions on crash severity during Arizona's monsoon season

Amin Ariannezhad, Yao Jan Wu

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Environmental factors, including adverse weather and light conditions, have been widely recognized as contributing factors to crash severity and frequency. Heavy downpours occur during the monsoon season in Arizona and surrounding areas during the summer. Considering the effects of light conditions on driver perception of adverse weather, and thus on crash risk, this study investigates the effects of weather and light conditions on crash severity by estimating four separate multinomial logit models for specific weather (heavy rainfall or clear) and light conditions (daytime or nighttime). Marked differences were found between these conditions in terms of the significant factors affecting crash severity. Drivers likely behave differently in different environmental conditions. Findings indicated that addressing factors such as age groups, speed limits, roadway types, slow driving in heavy rain, and excessive speeding with safety strategies and educational efforts may improve traffic safety during heavy rainfall as well as in clear weather. Various other significant factors are discussed and compared based on the weather and light conditions models.

Original languageEnglish (US)
Pages (from-to)579-594
Number of pages16
JournalJournal of Transportation Safety and Security
Issue number6
StatePublished - Nov 2 2019
Externally publishedYes


  • adverse weather
  • crash severity
  • heavy rainfall
  • light condition
  • monsoon season
  • multinomial logit model

ASJC Scopus subject areas

  • Transportation
  • Safety Research


Dive into the research topics of 'Effects of heavy rainfall in different light conditions on crash severity during Arizona's monsoon season'. Together they form a unique fingerprint.

Cite this