Road design

Cover of Guide to Road Design Part 3: Geometric Design
Guide to Road Design Part 3: Geometric Design
  • Publication no: AGRD03-16
  • ISBN: 978-1-925451-24-5
  • Published: 28 September 2016
  • Edition: 3.2

Guide to Road Design Part 3: Geometric Designprovides road designers and other practitioners with information about the geometric design of road alignments.

Design parameters include: road classification; design speeds; design vehicles; alignment controls; cross-section components, including travel lanes, shoulders and verges; and provisions for public transport and cyclists.

Speed parameters include: operating speed, desired speed and design speed; and their relationship with each other.

Horizontal and vertical alignments include development and application of: circular curves; superelevation; grades; vertical curves; procedures for the grading of a road alignment; and determination of sight distances across vertical curves.

Edition 3.2 of the Guide provides corrections to:

  • Section 3.4.2 Intermediate Speed Rural Roads
  • Section 4.8.7 (Table 4.18: Exclusive bicycle lane dimensions in urban areas)
  • Section 7.8, (Table 7.12: Minimum radii with adverse crossfall)
  • Reference list
  • Appendix H (Figure H3: Variation of friction factor with speed)

Edition 3.1 of the Guide corrects Table 8.11: Minimum length vertical curves for reconstruction.

Edition 3.0 of the Guide contains minor editorial and technical changes throughout. Key new information and updates are:

  • Section 1.4: Additional information and expansion on the design objectives.
  • Section 2.2: Additional information on vulnerable road users, particularly motorcyclists (Section 2.2.4) and new information on emergency aircraft runway strips (Section 2.2.8).
  • Section 3.5: Guidance for determining desired speed for rural roads and on steep grades (Section 3.5.1 – 3.5.4).
  • Section 4.2: Additional guidance on crown line (Section 4.2.3) and rural road lane and shoulder widths (Section 4.2.6).
  • Section 4.3: Additional guidance on shoulder widths and sealing (Section 4.3.3 – 4.3.4).
  • Section 4.4: Additional guidance on verge slopes (Section 4.4.2) and rounding (Section 4.4.3).
  • Section 4.8: Additional information on providing bicycle lanes (Section 4.8.4 – 4.8.12).
  • Section 7.7: New guidance on a procedure for designing superelevation (Section 7.7.1) and development of superelevation on shoulders (Section 7.7.12).
  • Section 8.2: New information outlining a procedure for checking critical vertical clearance points (Section 8.2.2).
  • Section 9.9: Additional guidance on selecting a starting and terminating point of an auxiliary lane Section 9.9.1.
  • New Appendices:
    • Appendix B: Emergency aircraft runway strips
    • Appendix E: Narrow median treatments with wire rope safety barrier
    • Appendix F: Guidance for wide centreline treatments
    • Appendix G: Flowcharts and table for determining stopping sight distance requirements for curves with barriers.