Attachment 9 - Traffic Engineering Report

Figure 7.2: Existing Myall Street / State Route 6 / Nandroya Road Intersection Layout

Table 7.3 summarises the analysis outputs. Detailed analysis output summaries are included in Appendix C.

Table 7.3: Summary of Sidra Outputs (Myall Street / State Route 6 / Nandroya Road Intersection)
 Case                                  Degree of        Worst Average   Worst Level     95th Percentile Critical Queue (m)
                                       Saturation (%)   Delay (sec)     of Service
                                                                                        East        South        West
 AM Survey Case 2019                   26.5             9.9             A               9.4         3.4          9.5
 AM Base Case 2024                     29.3             9.9             A               10.8        4.0          10.9
 AM Project Case 2024                  30.3             9.9             A               11.4        4.1          11.3
 PM Survey Case 2019                   19.7             9.8             A               8.5         2.3          6.3
 PM Base Case 2024                     21.8             9.8             A               9.7         2.6          7.1
 PM Project Case 2024                  22.2             9.8             A               10.0        2.7          7.5

The analysis confirms that the existing intersection would have spare capacity at the opening-year of the
proposed development (2024) with the highest degree of saturation being 30.3% (85% is the generally
acceptable threshold) during the 2024 AM peak hour period with a maximum average delay of 10 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
turnmovement 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.”

As indicated in Table 7.3 above, the maximum for the opening ‘without development’ scenario is calculated
to be 10 seconds, while the additional traffic demands associated with the proposed development would
result in a maximum average delay of 10 seconds. Both of these values are within the nominated threshold
of 42 seconds. This indicates that no mitigating intersection upgrades are required to accommodate the
development.


Site: Lot 2 & 3 Myall Street, Cooroy                                                                                    26
Reference: 19BRT0357