minutes - City of Stirling

MINUTES OF THE ORDINARY MEETING OF COUNCIL
18 SEPTEMBER 2012
In relation to the submitted parking study, the following comments were made:-
The methodology for assessing the peak design parking demand is indicated as
follows:-
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Analyse door counts to understand the existing profile of activity over an entire
year;
Undertake parking utilisations surveys to determine existing usage patterns;
Derive factors that model the impacts of peak spreading, Sunday trading and
operation efficiency.
Apply these factors to observed parking demand to determine required supply of
car parking on design day.
This methodology is considered sound and has been utilised previously by other
engineering consultants to determine the peak car parking supply on the designated
design day.
Westfield Innaloo Shopping Centre (WISC) includes a total parking provision of 1,851
spaces. Under the heading Existing Parking Demand Surveys on page 2 of the
Assessment, it is indicated that the observed peak parking demand for WISC was
1,482 spaces. Figure 1 under this heading plots the theoretical and observed parking
occupancy. While this is noted, the vertical axis in Figure 1 shows only 0-3% for Total
Daily Occupancy – this appears to be an error, as it is unlikely that the maximum Daily
Occupancy is within the 0-3% range.
The daily Door Count on the survey date (5 July 2012) was 19,326 patrons. On the
90 th percentile Thursday (which is described as the 5 th busiest Thursday of the year),
the daily Door Count was 22,682 patrons. As such, a factor of 1.17 has been applied
to the parking utilisation figures (i.e. 22,682/19,326 = 1.17).
The Assessment provides evidence from previous shopping centre surveys to show
that the percentage of daily visits that occurs during the single peak hour reduces
during the busier days of the year. Based on the door counts, it has been found that
the observed parking survey date was equivalent to the 25 th busiest Thursday of the
year, whereas the ‘design day’ is the 5 th busiest Thursday of the year. Previous
shopping centre surveys showed that the peak hour percentage of daily door counts
was 11.9% on the 25 th busiest Thursday and 11.5% on the 5 th busiest survey. Thus a
3.4% reduction factor has been applied to account for this peak hour spreading (i.e.
11.5/11.9=0.966).
The Assessment applies a 95% parking efficiency factor to account for vehicles that
are manoeuvring, waiting or circulating the car park. It is understood that this parking
efficiency factor is described in the Urban Land Institute & National Parking
Association’s document titled “The Dimensions of Parking”, and is therefore accepted.
The parking efficiency factor is 1.052 (i.e. 1/0.95 = 1.052)
Based on these three (3) factors, the Design Parking Requirement for WISC would be
1,762 spaces (i.e. 1,482 spaces x 1.17 x 0.966 x 1.052).
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