F - Traffic Response and Revised Traffic Impact Assessment (17.09.19)

20 Hofmann Drive, Noosaville | Traffic Impact Assessment


10.0 Assessment Criteria
Traffic analysis (SIDRA) has been undertaken to determine potential operational impacts associated with
the proposed development on the surrounding road network. The main criteria utilised to assess
intersection performance is the ‘Degree of Saturation’ (DOS), which is the ratio of maximum demand
volume to capacity at an intersection. The Department of Transport and Main Roads’ (DTMR’s)
Guidelines for Assessment of Road Impacts of Development (GARID) provides guidance in relation to the
limit of acceptable operation based on the intersection type.

The recommended DOS thresholds are summarised in Table 7.1.

Table 10.1 Adopted Assessment Criteria (DOS)
                Intersection Type                                                                        DOS Threshold
                Priority Controlled                                                                          0.80
                   Roundabouts                                                                               0.85
                      Signals                                                                                0.90

In addition to the above, we also utilised ‘critical delay’ and Level of Service (LOS) thresholds for the
priority-controlled intersection. It is noted that the ‘critical delay’ represents the worst average delay
for an individual movement at the intersection. The NSW Roads and Traffic Authority’s Guide to Traffic
Engineering Developments provides guidance in relation to average delay and LOS thresholds.

The LOS thresholds are summarised in Table 7.2.

Table 10.2 Adopted Assessment Criteria (Average Delay & LOS)
                        Level of Service (LOS)                                                    Average Delay / Vehicle
                                       A                                                                  < 14 seconds
                                       B                                                                15 to 28 seconds
                                       C                                                                29 to 42 seconds
                                       D                                                                43 to 56 seconds
                                       E                                                                57 to 70 seconds
                                       F                                                                  > 70 seconds




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