Attachment 9 - Traffic Engineering Report

Table 7.2 summarises the analysis outputs. Detailed analysis output summaries are included in Appendix C.

Table 7.2: Summary of Sidra Outputs (Myall Street / Site Access Intersection)
 Case                                  Degree of        Worst Average   Worst Level   95th Percentile Critical Queue (m)
                                       Saturation (%)   Delay (sec)     of Service
                                                                                      East        South        West
 AM Project Case 2024                  33.8             23.3            C             0.7         8.6          0
 AM Project Case 2034                  50.4             40.3            E             0.8         12.5         0
 PM Project Case 2024                  24.4             16.6            C             0.2         5.9          0
 PM Project Case 2034                  33.8             24.1            C             0.2         8.6          0

The analysis confirms that the driveway access intersection would have spare capacity at the opening-year
and 10-year design horizon of the proposed development (2024 and 2034) with the highest degree of
saturation being 50.4% (85% is the generally acceptable threshold) during the 2034 PM peak hour period
with a maximum average delay of 41 seconds.

As outlined in DTMR’s Guide to Traffic Impact Assessment, the average delay metric is the key performance
measure for priority-controlled intersections. It states that “where average peak hour delays for any turn
movement exceeds 42 seconds (the Level of Service C/D threshold) then the intersection should be
upgraded for safety reasons where it is practical to do so.”

The analysis demonstrates that the critical period in terms of average delay is the AM case. As indicated in
Table 7.2 above, the maximum delay for the 10-year design horizon scenario is calculated to be 40.3
seconds, which is within the nominated threshold of 42 seconds. This indicates that no mitigating
intersection upgrades are required to accommodate the development beyond the turn treatments
proposed.

7.1.3        Conclusion
Based on the above analysis, it is concluded that the proposed access configuration is adequate to
accommodate the traffic demands associated with the proposed development at the opening year and 10-
year design horizon. It is anticipated that the future works to include turn lane treatments will cater for the
base traffic demands and the proposed additional traffic associated with the development.

7.2 Myall Street/ State Route 6/ Nandroya Road Roundabout Assessment
7.2.1        SIDRA Analysis
The existing intersection configuration has been analysed for the 2024 traffic volume scenario. Figure 7.2
shows the modelled intersection configuration.




Site: Lot 2 & 3 Myall Street, Cooroy                                                                                  25
Reference: 19BRT0357