Road safety

Cover of Verification of Austroads Road Design Criteria Based on Objective Safety Evidence
Verification of Austroads Road Design Criteria Based on Objective Safety Evidence
  • Publication no: AP-T320-17
  • ISBN: 978-1-925451-70-2
  • Published: 3 May 2017

This report provides a compendium of recent and robust evidence on the relationships between twenty key geometric design criteria and safety outcomes.

The project critically reviewed quality research sources to identify crash modification factors (CMFs) for such road design criteria as horizontal curvature, lane and sealed shoulder widths, sag and crest design values and various longitudinal sight distance requirements.

The review of findings by the Project Advisory Group, consisting of the Task Force members, largely resulted in verification of the current design criteria values as published in the Guide to Road Design Part 3: Geometric Design. The report highlights areas for further investigation to refine the current understanding or to enable economic appraisal of potential future changes.

The study reviewed potential for detailed design applications of the Australian National Road Assessment Model (ANRAM) and Interactive Highway Safety Design Model (IHSDM) in Australia and New Zealand. The review found both to be feasible but requiring further adaptations.

The report will assist Austroads Road Design Task Force in future reviews of Austroads road design guidance.

  • Summary
  • 1. Introduction
    • 1.1. Purpose and Objectives
    • 1.2. Background
  • 2. Method
    • 2.1. Project Tasks
      • 2.1.1. Formation of the Project Advisory Group
      • 2.1.2. Literature Scan and Review
      • 2.1.3. Collection of Objective Safety Evidence for Selected Design Elements
      • 2.1.4. Consultation and Recommendations
    • 2.2. Terms Used
  • 3. Findings and Recommendations
    • 3.1. Tangent Length between Curves
    • 3.2. Sealed Shoulder Width on Curves
    • 3.3. Lane Width on Curves
    • 3.4. Pavement Width on Curves
    • 3.5. Grade on Curves
    • 3.6. Skid Resistance (Friction) on Curves
    • 3.7. Curve Length
    • 3.8. Curve Frequency
    • 3.9. Curve Radius
    • 3.10. Curve Superelevation
    • 3.11. Sight Distance at Curves
    • 3.12. Vertical and Horizontal Curvature Combined
    • 3.13. Sight Distance at Crests
    • 3.14. Vertical Grade on Tangents
    • 3.15. Sag K Value on Tangents
    • 3.16. Crest K Value on Tangents
    • 3.17. Lane Width on Tangents
    • 3.18. Sealed Shoulder Width on Tangents
    • 3.19. Median Width
    • 3.20. Sight Distance
    • 3.21. Software Model for Safety Evaluation of Road Designs
  • Findings
  • Robustness and Applicability
  • Considerations
  • Advisory Group Recommendations
  • References
  • Findings
  • Robustness and Applicability
  • Considerations
  • Advisory Group Recommendations
  • References
  • Findings
  • Robustness and Applicability
  • Considerations
  • Advisory Group Recommendations
  • References
  • Findings
  • Robustness and Applicability
  • Considerations
  • Advisory Group Recommendations
  • References
  • Findings
  • Robustness and Applicability
  • Considerations
  • Advisory Group Recommendations
  • References
  • Findings
  • Robustness and Applicability
  • Considerations
  • Advisory Group Recommendations
  • References
  • Findings
  • Robustness and Applicability
  • Considerations
  • Advisory Group Recommendations
  • References
  • Findings
  • Robustness and Applicability
  • Considerations
  • Advisory Group Recommendations
  • References
  • Findings
  • Robustness and Applicability
  • Considerations
  • Advisory Group Recommendations
  • References
  • Findings
  • Robustness and Applicability
  • Considerations
  • Advisory Group Recommendations
  • References
  • Findings
  • Robustness and Applicability
  • Considerations
  • Advisory Group Recommendations
  • References
  • Findings
  • Robustness and Applicability
  • Considerations
  • Advisory Group Recommendations
  • References
  • Findings
  • Robustness and Applicability
  • Considerations
  • Advisory Group Recommendations
  • References
  • Findings
  • Robustness and Applicability
  • Considerations
  • Advisory Group Recommendations
  • References
  • Findings
  • Robustness and Applicability
  • Considerations
  • Advisory Group Recommendations
  • References
  • Findings
  • Robustness and Applicability
  • Considerations
  • Advisory Group Recommendations
  • References
  • Findings
  • Robustness and Applicability
  • Considerations
  • Advisory Group Recommendations
  • References
  • Findings
  • Robustness and Applicability
  • Considerations
  • Advisory Group Recommendations
  • References
  • Findings
  • Robustness and Applicability
  • Considerations
  • Advisory Group Recommendations
  • References
  • Findings
  • Robustness and Applicability
  • Considerations
  • Advisory Group Recommendations
  • References
  • 4. Summary and Discussion
  • 5. Conclusions
  • References
  • Appendix A Software Models for the Safety Evaluation of Road Designs
  • A.1 Recommendations
  • A.2 Australian National Risk Assessment Model (ANRAM)
  • A.3 Interactive Highway Safety Design Model (IHSDM)
  • Could IHSDM be tailored for use in road design in Australia and New Zealand?