RFI - Attachment 2- Technical Memorandum

The results of the analysis indicate that the four-legged roundabout arrangement operates within the typical
performance thresholds (DOS ≤ 0.85 for roundabout, delay <42 seconds), for all assessed scenarios.
It is noted that the assessed land use combination has been advised as likely developable uses over the
lots. It is acknowledged that other uses may eventually be developed on the lots which may yield different
trip generation, however given the operational results of the intersection indicate that there is plenty of
capacity available for all key factors (DOS, delay and queues), it is considered that the proposed form will be
able to accommodate the expected traffic demands for a number of higher generating uses. Nevertheless, a
detailed traffic assessment would be required to be undertaken when the Development Applications for each
lot are submitted which would ensure that the proposed access form is appropriate.
Following confirmation that the fourth leg to the roundabout is acceptable from a capacity point of view,
Cardno has prepared a concept sketch for the proposed layout of the roundabout with the inclusion of the
fourth access leg.
The proposed concept sketch is shown on Figure 6-2 and enclosed in Appendix C. It is illustrated that a
fourth approach to the roundabout is able to be accommodated. One approach lane is shown at Lot 25,
which is sufficient to accommodate the turning movements associated with the lot 23, 24, and 25
developments, with spare capacity.
             Proposed Roundabout Configuration




Source: Nearmap




QTT19017 Tech Memo 2019 04 23.docx                                                                   Page 16