Effect of Pavement Condition on Accident Rate

In this study, analysis was performed on highways in the states of Arizona, North Carolina and Maryland for the years between 2013 and 2015 to investigate the relationship between accident rate and pavement ride quality (roughness) and rut depth. Two main types of data were collected: crash data from the accident records and International Roughness Index (IRI) and rut depth data from the pavement management system database in each state. Crash road segments represented 37-48 percent of the total length of the network using 1-mile segments. IRI and rut depth values for crash and non-crash segments were close to each other, suggesting that roughness and rutting are not the only factors affecting number of crashes but possibly in a combination with other factors such as traffic volume, human factors, etc. Sigmoidal function regression analysis was performed to study the relationship between crash rate and both IRI and rut depth. In all cases, the crash rate did not basically increase up to a critical IRI value of 210 inches/mile or a critical rut depth value of 0.4 inches. When the IRI or rut depth increased above these critical values the crash rate largely increased. This is a key conclusion that provides empirically derived thresholds for safety concerns. If transportation agencies keep their road network below these critical pavement conditions, the crash rate would largely decrease. In summary, it can be concluded that both ride quality and rut depth affect crash rate and highway maintenance authorities need to maintain good pavement conditions in order to reduce crash occurrences.

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  • Summary URL:
  • Supplemental Notes:
    • This document was sponsored by the U.S. Department of Transportation, University Transportation Centers Program.
  • Corporate Authors:

    Arizona State University


    National Transportation Center at Maryland

    1124 Glenn Martin Hall
    University of Maryland
    College Park, MD  United States  20742

    Office of the Assistant Secretary for Research and Technology

    University Transportation Centers Program
    Department of Transportation
    Washington, DC  United States  20590
  • Authors:
    • Vinayakamurthy, Mounica
    • Mamlouk, Michael
    • Underwood, Shane
    • Kaloush, Kamil
  • Publication Date: 2017-6


  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Appendices; Figures; Photos; References; Tables;
  • Pagination: 67p

Subject/Index Terms

Filing Info

  • Accession Number: 01667494
  • Record Type: Publication
  • Report/Paper Numbers: NTC2016-SU-R-2
  • Created Date: Mar 13 2018 11:08AM