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Cover of Updating Intersection Sight Distance in Austroads Guide to Road Design
Updating Intersection Sight Distance in Austroads Guide to Road Design
  • Publication no: AP-R769-26
  • ISBN: 978-1-923617-60-5
  • Published: 7 August 2026

The purpose of this report is to enhance safety and efficiency at intersections by informing best practice approaches. This report summarises the fundamental principles and best practice guidance on intersection sight distance across various modes of transport, identifying existing gaps and inconsistencies while presenting opportunities for harmonisation.

It employs an evidence-led methodology consisting of a comprehensive literature review, stakeholder engagement, and the formulation of recommendations aimed at improving the Austroads Guide to Road Design Part 4A: Unsignalised and Signalised Intersections. The literature review underscores key principles such as accessibility and safety while highlighting significant variations in sight distance standards nationally and internationally. Stakeholder engagement contributed vital insights that enhanced the project's social acceptability and technical robustness.

The report ultimately advocates for clearer and consistent default values for critical design parameters in future updates to Austroads guidelines, thereby aiming to enhance safety and efficiency at both signalised and unsignalised intersections. The outcomes seek to ensure alignment with best practice and facilitate safer road corridors for all users, emphasising the importance of collaboration among jurisdictions and disciplines to adapt to evolving needs and technologies.

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  • Summary
  • 1. Introduction
    • 1.1 Purpose
    • 1.2 Background
    • 1.3 Scope
    • 1.4 Methodology
      • 1.4.1 Process for incorporating practice amendments into Guides
  • 2. Literature Review – Problem 1
    • 2.1 Austroads documents
      • 2.1.1 Austroads Guides – General
      • 2.1.2 Austroads Guide to Road Design Part 4A, Unsignalised and Signalised Intersections
    • 2.2 Australian and New Zealand supplementary guidance – summary of findings
    • 2.3 Australian and New Zealand major project specifications
    • 2.4 International guidance – summary of findings
  • 3. Literature Review – Problem 2
    • 3.1 Austroads documents – trucks
      • 3.1.1 Austroads Guide to Road Design Part 4A, Unsignalised and Signalised Intersections
    • 3.2 Summary of findings – provision for trucks
    • 3.3 Austroads documents – bicycles
      • 3.3.1 Austroads Guide to Road Design Part 6A: Paths for Walking and Cycling
      • 3.3.2 Austroads Cycling Aspects of Austroads Guides (2017)
    • 3.4 Summary of findings – bicycles
    • 3.5 Austroads documents – motorcycles
      • 3.5.1 Austroads Guide to Road Design Part 1: Objectives of Road Design
      • 3.5.2 Austroads report AP-R515-16
      • 3.5.3 Austroads report AP-R688-23
    • 3.6 Summary of findings – motorcycles
    • 3.7 Austroads documents – buses
    • 3.8 AASHTO – buses
  • 4. Literature Review – Problem 3
    • 4.1 Austroads documents
      • 4.1.1 Austroads Guide to Road Design Part 3
      • 4.1.2 Austroads Guide to Road Design Part 4A, Unsignalised and Signalised Intersections
      • 4.1.3 Austroads Guide to Road Design Part 4C
      • 4.1.4 Austroads Guide to Traffic Management Part 10
    • 4.2 Australian Road Rules
    • 4.3 Australian Standards
      • 4.3.1 Australian Standards 1742.14:2014
    • 4.4 Summary of findings – signalised intersections
  • 5. Literature Review – Other Documents
  • 6. Assessment and Recommendations – Problem 1
    • 6.1 Assessment – Problem 1
      • 6.1.1 Current AGRD guidance – comparison of ASD, SISD and MGSD
      • 6.1.2 International guidance literature review outcomes
    • 6.2 Immediate recommendations – Problem 1
      • 6.2.1 Identified Issues with Austroads Guide to Road Design Guidance
      • 6.2.2 Equal presentation of ASD vs SISD vs MGSD within AGRD
    • 6.3 Longer-term recommendations – Problem 1
      • 6.3.1 Identified issues with Austroads Guide to Road Design guidance
      • 6.3.2 Overall review of Austroads intersection sight distance models
      • 6.3.3 Specific guidance for urban/brownfields vs rural/greenfields environments
    • 6.4 Suggested improvements to other guides and documents – Problem 1
      • 6.4.1 Equal presentation of ASD vs SISD vs MGSD within AGTM
      • 6.4.2 Review of standard wording of project specification templates
  • 7. Assessment and Recommendations – Problem 2
    • 7.1 Assessment – Problem 2
      • 7.1.1 High level assessment – which sight distance models are applied across different road user groups
      • 7.1.2 Specific guidance in AGRD – trucks
      • 7.1.3 Specific guidance in AGRD – cyclists
      • 7.1.4 Specific guidance in AGRD – buses
      • 7.1.5 Specific guidance in AGRD – other user groups
    • 7.2 Immediate recommendations – Problem 2
      • 7.2.1 Amendment to ASD guidance for trucks
      • 7.2.2 Provision of specific SISD guidance for trucks
      • 7.2.3 Provision of general intersection sight distance guidance for buses
    • 7.3 Longer term recommendations – Problem 2
      • 7.3.1 Provision of specific MGSD guidance for trucks
      • 7.3.2 Provision of specific SISD and MGSD guidance for bicycles
      • 7.3.3 Assessment of appropriate deceleration rates for buses
      • 7.3.4 Provision of general guidance for other road users
    • 7.4 Suggested improvements to other guides and documents – Problem 2
      • 7.4.1 Misalignment between AGRD and NHVR stopping sight distance guidance
  • 8. Assessment and Recommendations – Problem 3
    • 8.1 Assessment – Problem 3
      • 8.1.1 High level considerations for signalised intersections
      • 8.1.2 Detailed requirement considerations for signalised intersections
    • 8.2 Immediate recommendations – Problem 3
      • 8.2.1 Clarification of major road and minor road classification for signalised intersections
        Improvement: Reference to AS1742.14 for sight distance to signal displays
    • 8.3 Longer-term recommendations – Problem 3
      • 8.3.1 Overall review of sight distance requirements at signalised intersections
  • 9. Proposed Wording Changes to AGRD Part 4A
  • 10. Summary of Longer-term Recommendations – AGRD Part 4A
  • 11. Summary of Recommendations – Other Documents
    • 11.1 AGRD – suggested recommendations (other documents)
    • 11.2 AGTM – suggested recommendations (other documents)
    • 11.3 Other documents – suggested recommendations
  • 12. Conclusion
  • References
  • Appendix A Literature Review – Problem 1
    • A.1 Australian State and New Zealand Supplementary Guidance
      • A.1.1 Department of Transport and Planning (Transport Victoria)
      • A.1.2 Queensland Department of Transport and Main Roads
      • A.1.3 Transport for New South Wales (TfNSW), New South Wales
      • A.1.4 Main Roads Western Australia (Main Roads WA)
      • A.1.5 Department of Infrastructure and Transport (DIT), South Australia
      • A.1.6 Department of State Growth (DSG), Tasmania
      • A.1.7 Transport Canberra and City Services (TCCS) Directorate, Canberra
      • A.1.8 Department of Infrastructure, Planning and Logistics, Northern Territory
      • A.1.9 NZ Transport Agency Waka Kotahi (NZTA)
    • A.2 International Guidance
      • A.2.1 Standard for Highway (DMRB), UK
      • A.2.2 Manual For Streets, UK
      • A.2.3 AASHTO, USA
      • A.2.4 California – Highway Design Manual
      • A.2.5 Florida – The FDOT (Florida Department of Transportation) Design Manual
      • A.2.6 Nevada Department of Transportation – Road Design Guide (2019 Edition)
      • A.2.7 Wisconsin Department of Transportation – Facilities Development Manual
      • A.2.8 South African National Roads Agency Limited, Geometric Design Guidelines
  • Appendix B Literature Review – Problem 2
    • B.1 International Guidance – Trucks
      • B.1.1 A Policy on Geometric Design of Highways and Streets (Edition 7 – 2018), AASHTO, USA (The Green Book)
      • B.1.2 California – Highway Design Manual
      • B.1.3 Florida – The FDOT (Florida Department of Transportation) Design Manual
      • B.1.4 Nevada Department of Transportation – Road Design Guide (2019 Edition)
      • B.1.5 Wisconsin Department of Transportation – Facilities Development Manual
    • B.2 Other Documents – Trucks
      • B.2.1 NHVR Heavy Vehicle Guidelines
    • B.3 Australian State and New Zealand Supplementary Guidance – Cyclists
      • B.3.1 Department of Transport and Planning (Transport Victoria)
      • B.3.2 Department of Transport WA
    • B.4 International Guidance – Cyclists
      • B.4.1 CROW, Netherlands
      • B.4.2 Standard for Highway (DMRB), UK
      • B.4.3 Cycling Infrastructure Design, UK
      • B.4.4 Cycling Embassy of Great Britain, UK
      • B.4.5 AASHTO, USA
      • B.4.6 NACTO, USA
      • B.4.7 California – Highway Design Manual
      • B.4.8 Wisconsin Department of Transportation – Facilities Development Manual
    • B.5 International Guidance – Motorcycles
      • B.5.1 Federal Highway Administration (FHWA), USA
      • B.5.2 NCHRP Project 20-68A, USA
      • B.5.3 Transport Research Laboratory (TRL) Road Safety Group, UK
      • B.5.4 Royal Society for the Prevention of Accidents (RoSPA)
  • Appendix C Literature Review – Problem 3
    • C.1 Australian State and New Zealand Supplementary Guidance
      • C.1.1 DIT Master Specification, South Australia – Operational Instruction
      • C.1.2 TfNSW Specification
      • C.1.3 Department of Transport and Planning (Transport Victoria)
    • C.2 International Guidance
      • C.2.1 Standard for Highway (DMRB), UK
      • C.2.2 AASHTO, USA
      • C.2.3 Florida – The FDOT (Florida Department of Transportation) Design Manual
      • C.2.4 South African National Roads Agency Limited, Geometric Design Guidelines
  • Appendix D Literature Review – Other Docs
    • D.1 Cox and Cole (2016)
    • D.2 Arndt et al. (2010)
    • D.3 Austroads Research Project AP-R610-20
    • D.4 PIARC: Human Factors in Road Design
    • D.5 PIARC: Models for Sight Distance in Road Design – A Worldwide comparison of Standards (A PIARC technical Report)
    • D.6 CASR Road Safety Research Report
    • D.7 Gap Acceptance at a Stop-Controlled Intersections
  • Appendix E Response from DMRB, UK
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Updates to Austroads Guide to Road Design: Parts 1, 3, 4, 4A, 6, 6A, 6B and 7
AP-R766-26
Guide to Road Design: Set
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