Road design

Cover of Rollover Crashes: Road Design Risk Factors and Infrastructure Solutions
Rollover Crashes: Road Design Risk Factors and Infrastructure Solutions
  • Publication no: AP-R607-19
  • ISBN: 978-1-925854-47-3
  • Published: 11 September 2019

Rollover crashes are an undesirable outcome in a substantial proportion of casualty crashes on high-speed roads. Rollovers are especially over-represented in run-off-road crashes due to their direct interaction with the roadside geometry.


This project sought to identify and quantify road and roadside design factors associated with rollover events in run-off-road crashes on high-speed rural roads and with high-severity outcomes. However, the data analysis provided largely non-statistically significant results, and few conclusive factors can be drawn from this work due to data limitations. Therefore, expected inputs to the update of the Guide to Road Design Part 6 are not available from this work. The update to the Guide to Road Design Part 6 will therefore use an alternative or theoretical method for estimating rollover crash risk as input to run-off-road crash mitigation. The literature review did reconfirm known contributing factors including sharp curvature, lack of sealed shoulders, roadside slopes and ditches, hitting unforgiving roadside objects (high-severity risk) and vehicle factors.

  • Summary
  • 1.         Introduction
    • 1.1        Background
    • 1.2        Objectives
    • 1.3        Scope
  • 2.         Methodology
    • 2.1        Literature Review
    • 2.2        AusRAP and Crash Data
    • 2.3        Modelling Methods
    • 2.4        Suggested Guide Amendments
  • 3.         Literature Review
    • 3.1        Risk Factors for Occurrence and Severity of Vehicle Rollover Crashes
    • 3.2        Summary of Rollover Risk Factors
    • 3.3        Measures to Reduce the Risk of Vehicle Rollovers
  • 4.         Modelling
    • 4.1        Analysis of Rollover Crashes
    • 4.2        Factors Affecting Rollover Crashes
    • 4.3        Risk Factors for Run-off-road Casualty Crashes
    • 4.4        Risk Factors for Rollover Events and Crash Severity
  • 5.         Discussion
    • 5.1        Interpretation
    • 5.2        Data Limitations
      • 5.2.1       Batter Slope
      • 5.2.2       Barriers
    • 5.3        Safe System Relevance
    • 5.4        Knowledge Gaps and Research Opportunities
    • 5.5        Summary of Findings
  • 6.         Conclusions and Suggested Amendments
    • 6.1        Suggested Guide Amendments
  • References
  • Appendix A                   Crash Data Analysis