Road Design

Recommended Changes to the Austroads Guide to Road Design

Publication no: AP-R693-23
ISBN: 978-1-922994-00-4
Published: 18 August 2023

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This report is one of the two reports that document the findings of a research project undertaken to update the Austroads Guide to Road Design (AGRD). The project reviewed the jurisdictional practices of developing supplements to the AGRD to identify means to make the content consistent and to harmonise processes. The objective of the project was to minimise supplements through improved management of the content.

The report describes the classification of material in the jurisdictional supplements to the AGRD.

The recommended changes to the AGRD were evaluated using three measures: relevance, impact and effort. The changes include:

topographical corrections
minor changes to the text to improve clarity
significant changes requiring discussion and review by the Road Design Task Force
new sections from the supplements
summaries of new sections
new sections with limited applicability that could be included in an Appendix.

The second report AP-R692-23 A Platform for Managing Supplements to the Austroads Guide to Road Design describes a cross-jurisdictional platform for managing jurisdictions’ supplements to the AGRD and the movement of supplement material into the AGRD.

Watch a detailed webinar presented by Dr Rod Troutbeck, Dr Hafez Alavi, Mark Lenske and Phil Rosser.

Summary
1. Introduction and Background
- 1.1 Background
- 1.2 Scope of This Report
- 1.3 Report Outline
- 1.4 Supplements reviewed for This Report
- 1.5 Notation Used in This Report
- 1.6 Acronyms Used in This Report
- 1.7 Summary of the Second Report
2. Summary of Previous Project Reports
- 2.1 Classification of Material in the Supplement
- 2.2 Review of Opinions on the Role and Content of Supplements
3. Moving Supplement Material into the Guide
- 3.1 Guidance from the Project Control Group and Others
- 3.2 Presentation by the Austroads Program Manager for Road Safety and Design
- 3.3 Concepts Used in This Report
4. Relevance, Impact and Effort
5. Examples of Recommended Inclusions
- 5.1 Corrections
- 5.2 Minor Changes to the Text
- 5.3 Minor Changes to the Text to Improve Clarity
- 5.4 Significant Changes Requiring Discussion and Review
- 5.5 New Sections
- 5.6 Recommendations for a Summary of a New Section
- 5.7 New Section with Limited Applicability
- 5.8 Sections That Have a Greater Urgency
6. Issues Requiring Significant Research
- 6.1 Lane and Shoulder Widths on Rural Roads
- 6.2 Batter Slopes
- 6.3 Side Friction and Minimum Curve Radius
- 6.4 Extended Design Domain (EDD) For Geometric Road Design
- 6.5 Right Turn Treatments at Intersections
- 6.6 Acceleration Distances
- 6.7 Warrants for Intersection Turn Treatments
- 6.8 Ramp Design Speeds
- 6.9 Tapers
- 6.10 Ramp Terminals
- 6.11 Road Surface Water Run-off
- 6.12 Shared Path Widths
- 6.13 Interaction Between the Operation of a Road and its Geometric Design
7. New Sections or Parts
- 7.1 Requirements for Multi-Combination Vehicles
- 7.2 Design of Low Volume Rural Roads
- 7.3 Design of Roads for Temporary Works
8. Concluding Remarks
- 8.1 Endorsement by the Road Design Task Force
  References
Appendix A Results from the Statements and Questionnaire
- A.1 Results from the Statements Put to the Project Control Group
- A.2 Results From the Survey Conducted by the Austroads Program Manager for Road Safety and Design
Appendix B Recommended Changes to Part 1
- B.1 Minor Changes to the Text in Part 1
  - B.1.1 Section 4.7: Coordination of Disciplines
- B.2 Significant Changes Requiring Discussion and Review in Part 1
  - B.2.1 Section 2.2.1: Road Planning
  - B.2.2 Section 4.1.2: Factors That Influence Design Standards
  - B.2.3 Section 4.5.2: Innovative and Emerging Treatments
  - B.2.4 Section 4.2: Phases of Design
  - B.2.5 Section 4.5.1: Design Exceptions
  - B.2.6 Section 4.7: Coordination of Disciplines
  - B.2.7 Section 5.2: Design Report
- B.3 New Sections for Part 1
  - B.3.1 Section 2.2.3: Designing for Safety
  - B.3.2 Section 2.3: Multi-Modal Considerations
  - B.3.3 Section 4.3: Context-sensitive Design
  - B.3.4 Appendix A: New Section on ‘Design Exceptions’
- B.4 Consideration for a Summary of a New Section for Part 1
  - B.4.1 Section 4.4.3: Application of the Design
  - B.4.2 Section 4.4: The Design Domain
Appendix C Recommended Changes to Part 2
Appendix D Recommended Changes to Part 3
- D.1 Corrections to Part 3
  - D.1.1 Section 3.6.4: Car Deceleration on Curves Graph
  - D.1.2 Section 4.7.2: Median Width
  - D.1.3 Section 5.3.1: Car Stopping Sight Distance
  - D.1.4 Section 7.5.4: Transition Curves
  - D.1.5 Section 7.10.1: Theoretical Considerations
  - D.1.6 Section 8.6.6: Reverse/Compound/Broken Back Vertical Curves
- D.2 Minor Changes to the Text in Part 3
  - D.2.1 Section 2.2.5: Design Speed and Operating Speed
  - D.2.2 Section 3.1: General (Speed Parameters)
  - D.2.3 Section 3.2.4 Design Speed
  - D.2.4 References in Notes to Figures
  - D.2.5 Section 4.7.2: Median Width
  - D.2.6 Section 5.2.3: Longitudinal Acceleration
- D.3 Minor Changes to the Text to Improve Clarity in Part 3
  - D.3.1 Superelevation Development
- D.4 Significant Changes Requiring Discussion and Revision in Part 3
  - D.4.1 Section 4.2.3: Crown Lines
  - D.4.2 Section 4.9: Bicycle Lanes
  - D.4.3 Section 7.5.1: Compound Curve
  - D.4.4 Section 7.7.3: Maximum Values of Superelevation
  - D.4.5 Section 7.7.10: Positioning of Superelevation Runoff without Transitions
- D.5 New Sections for Part 3
  - D.5.1 Section 4.1: General (Cross Section)
  - D.5.2 Section 4.4: Verge
  - D.5.3 Section 4.5: Batters
  - D.5.4 Section 4.6: Roadside Drainage
  - D.5.5 Section 6.3: Aesthetic Considerations
  - D.5.6 Section 7.1: General (Horizontal Alignment)
- D.6 Summary of a New Section for Part 3
  - D.6.1 Section 4.2.5: Urban Road Widths
  - D.6.2 Design of Floodways
  - D.6.3 Road Surface Drainage and Aquaplaning
  - D.6.4 Access Chambers
  - D.6.5 Section 9.4.1: General (Overtaking lanes)
  - D.6.6 Section 9.5.1: General (Climbing lanes)
- D.7 New Section with Limited Applicability for Part 3
  - D.7.1 Section 4.3: Shoulders
  - D.7.2 Section 4: Cross Section
  - D.7.3 Section 5.8: Intermediate Sight Distance
  - D.7.4 Section 7.6: Side Friction and Minimum Curve Size
Appendix E Recommended Changes to Part 4
- E.1 Minor Changes to the Text to Improve Clarity in Part 4
  - E.1.1 Appendix Section B.5.1: Pedestrian Crossings
- E.2 Significant Changes Requiring Discussion in Part 4
  - E.2.1 Section 7.3.2: Location (Median Openings)
  - E.2.2 Section 5.6.2: Radius of Turn
- E.3 New Sections for Part 4
  - E.3.1 Section 8.2.1 General Considerations for Design
- E.4 Summary of a New Section for Part 4
  - E.4.1 Section 3: Road Design Considerations for Intersections
  - E.4.2 Section 5.6.1: General (Design Vehicle Swept Path)
- E.5 New Section with Limited Applicability for Part 4
  - E.5.1 Section 10.2: Sight Distance (Rail Crossings)
Appendix F Recommended Changes to Part 4A
- F.1 Corrections to Part 4A
  - F.1.1 Section 1.3: Design Criteria in Part 4A
  - F.1.2 Section 3.2.2: Sight Distance Requirements for Vehicles at Intersections
  - F.1.3 References
  - F.1.4 Appendix Section A2.2.5: EDD Safe Intersection Sight Distance (SISD)
- F.2 Minor Changes to the Text in Part 4A
  - F.2.1 Appendix Section A2.2.5: EDD Safe Intersection Sight Distance (SISD)
  - F.2.2 Section 6.5.1: General (Kerb and Channel)
  - F.2.3 Appendix Section A.2.2: Base and Check Cases
  - F.2.4 Appendix Section A.8: EDD for Median widths
- F.3 Minor Changes to the Text to Improve Clarity in Part 4A
  - F.3.1 Section 3.2.3: Minimum Gap Sight Distance
- F.4 Significant Changes Requiring Discussion in Part 4A
  - F.4.1 Section 6.4.1: General (Road Width Between Kerbs and Between Kerb and Safety Barrier)
- F.5 Significant Changes Requiring Review in Part 4A
  - F.5.1 Section 3.2.2: Safe Intersection Sight Distance (SISD)
  - F.5.2 Section 5.2.1: Components of Deceleration Turn Lanes
  - F.5.3 Section 5.3.3: Merge Taper Tm
  - F.5.4 Section 6.1.2: Raised Medians
- F.6 New Sections for Part 4A
  - F.6.1 Section 4: Types of Intersection and Their Selection
  - F.6.2 Section 8.2: Rural Left-turn Treatments
- F.7 Summary of a New Section for Part 4A
  - F.7.1 Section 2. Layout Design Process
  - F.7.2 Section 8.1 General (Left-turn Treatments)
  - F.7.3 Appendix Section A.6: EDD Treatment of a Constrained Left-turn Radius
  - F.7.4 Appendix A: Extended Design Domain (EDD) for Intersections
Appendix G Recommended Changes to Part 4B
- G.1 Corrections to Part 4B
  - G.1.1 Section 1.2: Scope of This Part
  - G.1.2 Section 2.3: Design Procedure
  - G.1.3 Section 4.8: Entry and Exit Widths
  - G.1.4 Appendix B: Roundabout Study and Program
- G.2 Minor Changes to the Text in Part 4B
  - G.2.1 Section 2.2: Design Principles
- G.3 Minor Changes to the Text to Improve Clarity in Part 4B
  - G.3.1 Section 2.2: Design Principles.
- G.4 Significant Changes Requiring Discussion and Review in Part 4B
  - G.4.1 Section 3.3: Stopping Sight Distance for Trucks
  - G.4.2 Section 4.6.3: Encroachment Areas
  - G.4.3 Section 5.2.2: Designing Roundabouts for Pedestrians
  - G.4.4 Section 5.3.6: Bicycle Paths and Shared Paths at Roundabouts
- G.5 New Sections for Part 4B
  - G.5.1 Section 4.10: Superelevation, Gradient and Drainage
- G.6 Recommendation for a Summary of a New Section for Part 4B
  - G.6.1 Section 4.10: Superelevation, Gradient and Drainage
  - G.6.2 Section 5.1: Introduction (Pedestrian and Cyclist Treatments)
Appendix H Recommended Changes to Part 4C
- H.1 Corrections to Part 4C
  - H.1.1 Section 7.5: Safe Intersection Sight Distance
  - H.1.2 Section 10: Ramp Terminals at Major Roads
  - H.1.3 Section 10.2.1: Exit Ramp Alignment at Minor Road Terminals
- H.2 Minor Changes to the Text to Improve Clarity in Part 4C
  - H.2.1 Section 7.5: Safe Intersection Sight Distance
  - H.2.2 Section 11.2.1: Single-lane Exits
- H.3 Significant Changes Requiring Discussion and Review in Part 4C
  - H.3.1 Section 2.4.1: Interchange elements
  - H.3.2 Section 7.2: Stopping Sight Distance on the Major Road and Minor Road
  - H.3.3 Section 11.1: General (Ramp Terminals at the Major Road)
  - H.3.4 Section 11.2.2: Two-lane Exits
  - H.3.5 Section 11.2.3: Exits to Two High-speed Roadways
- H.4 Summary of a New Section for Part 4C
  - H.4.1 Section 7.2: Stopping Sight Distance on the Major Road and Minor Road
  - H.4.2 Section 10.2.2: Entry Ramp Alignment at Minor Road Terminals
Appendix I Recommended Changes to Part 5
- I.1 Corrections to Part 5
  - I.1.1 Section 3.6.3: Erosion Estimates
Appendix J Recommended Changes to Part 5A
- J.1 Corrections to Part 5A
  - J.1.1 Section 5.2.2: Drainage Inlet Types
- J.2 Minor Changes to the Text to Improve Clarity in Part 5A
  - J.2.1 Section 4.9.3: Texture Depth
  - J.2.2 Section 4.11: Quick Assessment
- J.3 Significant Changes Requiring Discussion in Part 5A
  - J.3.1 Section 5.4.2: Pavement Spread and Gutter Flow Limits
  - J.3.2 Section 8.3: Sources of Moisture
Appendix K Recommended Changes to Part 5B
- K.1 Corrections to Part 5B
  - K.1.1 Section 2.3.3: Fundamental Equations
Appendix L Recommended Changes to Part 6A
- L.1 Corrections to Part 6A
  - L.1.1 Section 6.4: Treatments for Intersections of Paths with Paths
- L.2 Minor Changes to the Text in Part 6A
  - L.2.1 Section 5.5: Clearances, Batters and Need for Fences
- L.3 Minor Changes to the Text to Improve Clarity in Part 6A
  - L.3.1 Section 5.5.3: Batters and Fences
  - L.3.2 Section 5.1.4: Shared Paths
  - L.3.3 Section 5.6.2: Drainage
  - L.3.4 Appendix B: Speed Limiting Treatments
- L.4 Significant Changes Requiring Discussion and Review in Part 6A
  - L.4.1 Section 5.7.1: Bicycle Path Stopping Sight Distance
- L.5 New Sections for Part 6A
  - L.5.1 Section 2.5: Separated path
  - L.5.2 Section 6.5: Special Treatments for Intersections of Paths with Paths
Appendix M Recommended Changes to Part 6B
- M.1 Significant Changes Requiring Discussion in Part 6B
  - M.1.1 Bushfire Risk Planning and Design
  - M.1.2 Section 2.3.2: Pavement Surface Types
  - M.1.3 Section 4.4.5: Car Parking Area Layout Design
- M.2 New Sections for Part 6B
  - M.2.1 Section 4.1.6: Fences
- M.3 Summary of a New Section for Part 6B
  - M.3.1 Section 3: Roadside Amenity
  - M.3.2 Section 4: Roadside Infrastructure
Appendix N Recommended Changes to Part 7
- N.1 Significant Changes Requiring Discussion and Review in Part 7
  - N.1.1 Diverging Diamond Interchange
Appendix O Areas Requiring Significant Work
- O.1 Lane and Shoulder Widths
  - O.1.1 Urban Roads
  - O.1.2 Rural Roads
  - O.1.3 Appropriate Shoulder Widths on Cycle Routes
- O.2 Batter Slopes
- O.3 Side Friction and Minimum Curve Radius
- O.4 Right Turn Treatments at Intersections
  - O.4.1 Comments on the Use of AUR and CHR Right Turn Treatments in the Guide
  - O.4.2 Comments on the Use of AUR and CHR Right Turn Treatments in the Supplements
- O.5 Acceleration Distances
- O.6 Ramp Design Speeds
- O.7 Ramp Terminals
  - O.7.1 Additional Supplement Comments on Section 10
  - O.7.2 Additional Supplement Comments on Section 11
  - O.7.3 Additional New Sections in Part 4C
- O.8 Road Surface Water Run-off
- O.9 Shared Path Widths
- O.10 Interaction Between the Operation of a Road and its Geometric Design

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