220527 Sight Distance Assessment and IR Responses

Figure 3 – Proposed location of the vehicle crossover

Sight Distance Assessment against AS2890.1

An assessment of the proposed crossover location against the requirements of AS2890.1 for
Domestic Driveways has been undertaken.

Melaleuca St and Tristania St do not have a posted speed limit and as such are restricted to
50km/hr. In line with Section 2.3 of Queensland Streets and the radii of the horizontal
curves approaching the vehicle crossover, the likely design speed for vehicles approaching
from the east of the driveway is 25km/hr. In accordance with Figure 2.3.B of Queensland
Streets, the roundabout to the west is considered to be a “end condition” which is
designated to have a design speed of 20km/hr.

Section 3.2.4 of AS2890.1 details the minimum required sight distance for domestic
properties for roads with varying frontage road speeds. Figure 3.2 in AS2890.1 does not
contain any recommended sight distances for roads with a frontage road speed of less than
40km/h. Therefore, this assessment has been completed using a frontage road speed of
40km/hr even though the actual design speed has been demonstrated to be less than
40km/hr.

To determine the available sight distance the driver’s eye has been assumed to be 1.1m high
and the height of an oncoming vehicle has been assumed to be 1.25 m. These heights are in
line with Austroads guidelines for sight distance measurements. The available sight
distances from the approximate location of the driver’s eye on the proposed crossover to
Melaleuca St are shown in Figures 4 and 5.