Appendix D - traffic impact assessment

Table 3-4 Elm Street (Cooroy Connection Road) / Diamond Street intersection SIDRA assessment outcomes, 2018 Base
Year and 2028 Design Year – priority control (stop-sign)


                                     Degree of      Level of           95th Percentile Queue     Delay
 Scenario                            Saturation     Service (LOS)      Length (m)                (s)

Base Development Year 2018
2018 AM Peak Hour – without              1.33              F                     208                     33
development traffic
2018 AM Peak Hour – with                 1.76              F                     352                     61
development traffic
2018 PM Peak Hour – without              1.24              F                     191                     31
development traffic
2018 PM Peak Hour – with                 1.67              F                     389                     66
development traffic
Design Horizon Year 2028
2028 AM Peak Hour – without             12.29              F                    2,316                 1,053
development traffic
2028 AM Peak Hour – with                17.57              F                    2,584                 1,480
development traffic
2028 PM Peak Hour – without              8.67              F                    2,261                    853
development traffic
2028 PM Peak Hour – with                11.88               F                   2,432                 1,164
development traffic
Note: the above values are the “worst” values resulting from the assessment

The key outcome from the assessment is that some movements and legs are operating at an unacceptable Level of
Service (LOS) of “F” prior to the addition of development traffic volumes. The Level of Service was “F” at the eastern and
southern intersection approaches. The worst 95th percentile queue length was 2,584m occurring on the right turn
movement from the south approach on Elm Street. All values of degree of saturation are more than the upper limit
Practical Degree of Saturation of 0.80 for priority controlled intersections. Refer to SIDRA output in Appendix C.

Based on the analysis above, the proportion of the development traffic is less than 5% of the existing traffic movements
and the addition of the development traffic does not significantly impact on the performance of this intersection.




B14158ER01 | TRAFFIC IMPACT ASSESSMENT | PALM LAKES RESORTS                      COOROY RETIREMENT COMMUNITY | 19