Attachment 6 - Traffic Impact Assessment

2036 weekday AM peak with redevelopment:
                                       David Low Way
                                         4 34 850




                   Woodland         24
                   Drive            67




                                                 38 1050 26
                                                David Low Way



2036 weekday PM peak with redevelopment:
                                       David Low Way
                                         2 9 880




                   Woodland         42
                   Drive            53




                                                 22 910 35
                                                David Low Way


At the existing intersection, the critical right turn movement from Woodland Drive occurs in two stages,
with right turning traffic firstly crossing the northbound David Low Way traffic stream, before then storing
in the wide median area while waiting for an appropriate gap to enter the southbound David Low Way
traffic stream. Capacity analysis of the intersection thus requires a two-stage analysis.

For the first stage of the analysis, crossing the northbound David Low Way traffic stream, the following
steps were undertaken in Sidra:

(i)         A standard t-junction configuration was established, with separate left and right turn lanes on
            the Woodland Drive approach and with a separate right turn lane for right turns into Woodland
            Drive.

(ii)        The southbound through movement on David Low Way is set to zero.

(iii)       The gap parameters for the first stage of the right turn were altered to take account of the
            different configuration, being that the first stage of the right turn is a movement directly across
            the northbound traffic stream (not a right turn), and that any following right turn vehicles are not
            able to move across to the central median area until the first vehicle has completed the second
            stage of the right turn. To account for these factors, the “critical gap” for the first stage of the
            right turn was reduced from 7.0s to 5.0s (so that is the same as the Sidra default for the left
            turn movement) and the “follow-up headway” was increased to 10s.


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