Attachment 5 - Traffic Impact Assessment Final PTT · 132005.638.06

PRACTICE NOTE
GAP ACCEPTANCE AT UNSIGNALISED INTERSECTIONS




    As outlined above, Austroads guidance suggests that                            REFERENCES
    even the highest value of this calibration factor (ie
                                                                                   Austroads (1993). Guide to Traffic Engineering
    “high”) is likely to be conservative. Therefore, the
                                                                                   Practice Part 6: Roundabouts, Sydney.
    recommended approach is likely to be highly
    conservative.                                                                  Austroads (2020). Guide to Traffic Management Part
                                                                                   3: Transport Study and Analysis Methods, Sydney.
    TABLE 1: CALIBRATION FACTOR SELECTION
                                                                                   Austroads (2023). Guide to Road Design Part 4A:
     OPPOSING FLOW RATE            CALIBRATION FACTOR VALUE                        Unsignalised and Signalised Intersections, Sydney.
     0 – 625 pcu/h                                None                             Austroads (2023). Guide to Road Design Part 4B:
                                                                                   Roundabouts, Sydney.
     626 – 1,250 pcu/h                             Low
                                                                                   Li, Y., Hao, H., Gibbons, R., & Medina, A. (2022).
     1,251 – 1,875 pcu/h                         Medium
                                                                                   Analyzing Intersection Gap Acceptance Behavior with
     1,876+ pcu/h                                  High                            Naturalistic   Driving Data.       National Surface
                                                                                   Transportation Safety Centre for Excellence, Virginia.
                                                                                   Tian, Z., et al. (2000). A Further Investigation on
                                                                                   Critical Gap and Follow-Up Time. In Fourth
                                                                                   International Symposium on Highway Capacity (pp.
                                                                                   397-408), 27 June to 1 July 2000, Hawaii.

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                                                                                   The material contained in this practice note is of a
                                                                                   general nature, for information only. PTT accepts no
                                                                                   liability for any damage caused by any error or
                                                                                   omission contained herein.




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