RFI - 20210153 Maple St Traffic Assessment

 SIGHT DISTANCE ANALYSIS
Council has requested further detail regarding the sight lines available from the access in accordance with
Austroads Guide to Road Design Part 4A (AGRD4A), including the Safe Intersection Sight Distance (SISD) and
Minimum Gap Sight Distance (MGSD) when considering all parking spaces and bus bays are occupied.

As the driveway is considered to function as a property access, rather than an intersection, it is desirable for the
access to achieve the above distances, noted as the normal design domain (NDD), however the minimum standard
for an access is to be assessed using the extended design domain (EDD) criteria for SISD.


     4.1. Safe Intersection Sight Distance (SISD)
The SISD represents the sight distance on the major road from the eye height (1.1m) to observe a vehicle on the
minor road at 1.25m height, representing the upper part of the car as shown below in Figure 4-1 and Figure 4-2.




Figure 4-1 – SISD Plan– Figure 3.2 of AGRD4A




Figure 4-2 – SISD Long Section – Figure 3.2 of AGRD4A



The SISD is based on a combination of the decision time (D T), 85th percentile operating speed (V), coefficients of
deceleration (d) and longitudinal grade in the direction of travel (a), as described below




Project number 20210153                                                                                         Page 9 of 20
File 20210153 Maple St Traffic Assessment Report.docx, 2023-05-04 Revision 0

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