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Attachment 6 - Traffic Impact Assessment
Attached to the e-mail MCU16/0044 & REC16/0009 Development Application - Att 3F2 and Att 4,5,6 & 7 - Email 4 of 4.
NOOSA COUNCIL PROPOSED OFFICE BUILDING AND COMMUNITY USE BUILDING AT RUFOUS ST, PEREGIAN ASSESSMENT OF TRAFFIC IMPACTS AT THE WOODLANDS DRIVE / DAVID LOW WAY INTERSECTION PREPARED BY S A HOLLAND 28 APRIL 2016
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1.0 Introduction
This traffic report has been prepared for Noosa Council in relation to the proposed office building and
community use building at Rufous Street, Peregian as depicted on Sparks Architects drawings 97 SD
A.1.1, SD A.1.2, SD B1.1, SD C.1.1, and SD C.1.2, as well as on Callaghan & Toth drawing numbers
1532-01B, 1532-02B, 1532-03B, and1532-04B.
This report assesses traffic impacts of that proposal on operation of the Woodland Drive / David Low
Way intersection, and also assesses the quantum of parking provisions proposed for the office
component of the development. This report does not assess the proposed on-site traffic layouts, which
we understand is being undertaken by others.
The site locality is depicted in Figure 1.
Woodland Drive
Subject
Site
Figure 1: Locality Plan
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2.0 Proposed Development
The proposed development is depicted on Sparks Architects drawings 97 SD A.1.1, SD A.1.2, SD B1.1,
SD C.1.1, and SD C.1.2, as well as on Callaghan & Toth drawing numbers 1532-01B, 1532-02B, 1532-
03B, and1532-04B.
From a traffic engineering perspective the development involves the following elements:
(i) Construction of a new IT digital hub office building having a GFA of 554 sq m (including 30 sq
m café) fronting David Low Way.
(ii) Construction of new community house building having a GFA of 335 sq m fronting Rufous
Street. This includes 23 basement parking spaces accessed via Rufous St.
(iii) Conversion of the existing community house building at the southern corner of the David Low
Way / Woodland Drive intersection, to a new IT digital hub office building having a GFA of 329
sq m.
(iv) Construction of a new 59 space carparking area, plus 2 short term loading bays, having access
via the existing left turns only driveway to David Low Way, with 42 of those parking spaces
(and the 2 short term loading bays) on the IT digital hub office building allotment, and 17
spaces on the community house building allotment.
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3.0 Woodland Drive / David Low Way intersection assessment
3.1 Existing intersection configuration
The Woodland Drive / David Low Way intersection has a layout as depicted in Figure 2.
Figure 2: Existing Woodland Drive / David Low Way intersection
The intersection includes the following features:
(i) Vehicles are able to queue separately on the Woodland Drive approach to the intersection,
whether turning left or right onto David Low Way. Thus, left turning vehicles are not delayed by
vehicles waiting to turn right.
(ii) The median in David Low Way is about 8.5m wide (clear width between opposing through
traffic lanes on David Low Way). Thus, traffic undertaking the critical right turn movement from
Woodland Drive onto David Low Way is able to perform that movement in two stages, but firstly
crossing the northbound David Low Way traffic stream, and then waiting within the wide
median area while waiting for a gap in the southbound David Low Way traffic stream.
3.1 Existing traffic flows
As a basis for this assessment, peak period traffic counts were undertaken by Austraffic at the Woodland
Dr / David Low Way intersection on Thursday 17 September 2015 in the periods 7.30-9.00am and 2.30-
4.30pm and Saturday 19 September 2015 in the period 10.00am-12.00pm (those times were selected
based on the peak periods identified by recent extensive traffic flows in the nearby area). The surveys
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indicated weekday peak hour periods of 7.30-8.30am and 2.30-3.30pm, and a Saturday peak hour of
10.45-11.45am.
Existing peak hour traffic flows indicated by those surveys were as follows:
Existing Sept weekday AM peak:
David Low Way
4 5 490
Woodland 13
Drive 51
19 410 24
David Low Way
Existing Sept weekday PM peak:
David Low Way
2 8 476
Woodland 13
Drive 34
29 443 25
David Low Way
Existing Sept weekend peak:
David Low Way
1 5 443
Woodland 13
Drive 51
21 417 18
David Low Way
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We also have traffic count information over a weekly period in late January 2009 on the northern David
Low Way leg of the Heron Street roundabout. That traffic count information is attached at Appendix A.
That traffic count was at a location in David Low Way just north of the Heron Street roundabout, and thus
is on the same section of David Low Way as the southern leg of the Woodland Drive intersection. The
critical information from that week long survey is:
(i) Thursday was the busiest day of the week, and the peak hours were in the 8-9am and 3-4pm
period on each weekday.
(ii) Saturday was less busy than the weekdays, and Sunday was less busy than Saturday.
(iii) Peak hour traffic on weekdays were up to about 1200 vehicles per hour in the am and pm
peaks (this compares with 1018 vph in the am peak and 1032 vph in the pm peak on the
comparable road segment from the recent survey).
In addition, we also have results of peak hour traffic counts at the David Low Way / Heron Street
intersection from early May 2015, as well as a tube count in David Low Way near Woodland Drive from
March 2015. A comparison of corresponding peak hour traffic flows on David Low Way from three recent
sets of traffic count information follows:
David Low Way peak hour traffic flows
Northbound Southbound
AM PM AM PM
September 2015
(Southern leg of Woodland Dr intersection) 453 vph 456 vph 565 vph 535 vph
May 2015
(Northern leg of Heron St intersection) 944 vph 785 vph 754 vph 766 vph
March 2015 797 vph 667 vph 675 vph 657 vph
The traffic count information discussed above suggests that through traffic flows on David Low Way from
the September 2015 traffic count at the Woodland Drive intersection were unusually low for some
reason. Thus, for the purposes of this assessment of impacts at the David Low Way / Woodland Drive
intersection, we have used the higher May 2015 peak hour through traffic flows along David Low Way.
3.2 Estimation of traffic generated by potential redevelopment
The standard peak hour traffic generation rate for office developments is 3 vph per 100 sq m GFA with
an 80/20 directional split. At that rate the proposed 884 sq m office building would generate peak hour
traffic flows of 27 vehicles per hour. For the purposes of this assessment we have assumed it would
generate peak hour traffic flows of 30 vehicles per hour, with 24 arriving and 6 departing in the AM peak,
and vice versa in the PM peak.
We have assumed that the community house building would generate peak hour traffic flows at a similar
rate to an office development. Thus, we have assumed that the 335 sq m community house building
would generate peak hour traffic flows of 10 vehicles per hour, with 8 arriving and 2 departing in the AM
peak, and vice versa in the PM peak.
For completeness, we have also included allowance for traffic generated by potential future parking in
Rufous Street for an estimated 75 longer term staff parking spaces to accommodate employees of the
Peregian commercial area. For the 75 longer term staff parking spaces we have assumed they would
generate peak hour traffic flows of 40 vph, with all arriving in the AM and all departing in the PM.
Based on the weekday peak hour distribution of Heron Street traffic north and south along David Low
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Way, we have assumed that 60% of generated traffic would be oriented in the north along David Low
Way, with 40% being oriented in the south along David Low Way.
On the above basis, preliminary predicted peak hour traffic flows generated by the proposed
development, with allowance for future additional parking in Rufous Street, are as follows:
Predicted AM generated:
David Low Way
29 14
Woodland 1
Drive 1
19 4 2
David Low Way
Predicted PM generated:
David Low Way
1 2
Woodland 29
Drive 19
1 14 10
David Low Way
3.3 Future traffic projections
For the prediction of future year peak hour traffic flows at the Woodland Drive / David Low Way
intersection, we have conservatively adopted a base year scenario that comprises turning traffic flows to
and from Woodland Drive as indicated by the recent September 2015 survey, but we have adopted the
significantly higher through traffic flows along David Low Way as indicated by the Heron Street
intersection survey in May 2015. We have then made additional allowance for future traffic growth (at a
low rate of about 1%pa to the year 2036) along David Low Way.
Resultant traffic projections to the year 2036 with the proposed development fully operational, as well as
75 possible future parking spaces in Rufous Street are as follows:
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2036 weekday AM peak with redevelopment:
David Low Way
4 34 850
Woodland 24
Drive 67
38 1050 26
David Low Way
2036 weekday PM peak with redevelopment:
David Low Way
2 9 880
Woodland 42
Drive 53
22 910 35
David Low Way
At the existing intersection, the critical right turn movement from Woodland Drive occurs in two stages,
with right turning traffic firstly crossing the northbound David Low Way traffic stream, before then storing
in the wide median area while waiting for an appropriate gap to enter the southbound David Low Way
traffic stream. Capacity analysis of the intersection thus requires a two-stage analysis.
For the first stage of the analysis, crossing the northbound David Low Way traffic stream, the following
steps were undertaken in Sidra:
(i) A standard t-junction configuration was established, with separate left and right turn lanes on
the Woodland Drive approach and with a separate right turn lane for right turns into Woodland
Drive.
(ii) The southbound through movement on David Low Way is set to zero.
(iii) The gap parameters for the first stage of the right turn were altered to take account of the
different configuration, being that the first stage of the right turn is a movement directly across
the northbound traffic stream (not a right turn), and that any following right turn vehicles are not
able to move across to the central median area until the first vehicle has completed the second
stage of the right turn. To account for these factors, the “critical gap” for the first stage of the
right turn was reduced from 7.0s to 5.0s (so that is the same as the Sidra default for the left
turn movement) and the “follow-up headway” was increased to 10s.
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For the second stage of the right turn analysis, entering the southbound David Low Way traffic stream,
the following steps were undertaken in Sidra:
(i) A basic j-junction layout was established, without turn lanes, and with the left turn from
Woodland Drive prohibited.
(ii) The northbound David Low Way traffic flow was set to zero, as was the right turn from David
Low Way into Woodland Drive.
(iii) The gap parameters for the second stage right turn were altered to take account of the different
configuration, being that the right turn from the central median into the southbound traffic
stream is essentially the same as a left turn into the northbound traffic stream, and when that
vehicle enters the southbound traffic stream, there is not a vehicle waiting immediately behind it
in the median to follow it if there is a large gap in the southbound traffic. To account for these
factors, the “critical gap” for the second stage of the right turn was reduced from 7.0s to 5.0s
(so that is the same as the Sidra default for left turn movements) and the “follow-up headway”
was increased to 10s.
The Sidra analysis under predicted 2036 peak hour conditions with the redevelopment fully operational,
during the critical PM peak (when the right turn movement from Woodland Drive is significantly higher
than in the AM peak) using the procedure for the existing intersection as described above, indicates
satisfactory operation of the intersection with the following summary output:
2036 AM with redevelopment DOS Right turn queue (95th percentile)
existing intersection config
Stage 1 right turn 0.65 1.4 vehicles
Stage 2 right turn 0.57 1.1 vehicles
2036 AM with redevelopment DOS Right turn queue (95th percentile)
existing intersection config
Stage 1 right turn 0.50 1.4 vehicles
Stage 2 right turn 0.57 1.1 vehicles
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4.0 Quantum of parking for the IT digital hub office
The proposed IT digital hub buildings have a GFA of 884 sq m, including 30 sq m of café.
Council’s standard parking rate for office is 1 space per 20 sq m, and for café it is 1 space per 10 sq m.
Strict application of Council’s parking rates would require 42.7 (43) spaces for the office component and
3 spaces for the café, for a total of 46 spaces.
The proposed parking on the IT digital hub site is 42 spaces, representing a shortfall of 4 spaces when
compared with that required with strict application of Council’s requirements. However, the proposed
parking provision of 42 spaces is satisfactory, and a minor relaxation of Council’s standard parking
requirements is warranted on the following basis:
(i) The vast majority of users of the proposed café are likely to be already parked in the area for
other purposes, such as employees of the development, employees from the surrounding
commercial area, and local residents. Thus, customer parking requirements of the proposed
café are likely to be negligible.
(ii) Council’s parking requirement for office users is 1 space per 20 sq m, whereas in virtually all
other local authorities of South East Queensland, planning scheme parking rates for office are
1 space per 30 sq m GFA. At 1 space per 30 sq m GFA, the proposed 854 sq m of office
would require 29 parking spaces.
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5.0 Conclusion This traffic report has assessed impacts at the Woodland Drive / David Low Way intersection as a result of proposed office building and community use building at Rufous Street, Peregian. It is concluded that the existing intersection has sufficient capacity to operate in a satisfactory manner with the proposed development fully operational. In addition, the proposed quantum of 42 parking spaces for the proposed IT digital hub buildings would be sufficient to accommodate design parking demands. S A HOLLAND (RPEQ 05611) HOLLAND TRAFFIC CONSULTING PTY LTD 15.s.24.2 Page - 10
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APPENDIX A: LATE JANUARY 2009 WEEK LONG TRAFFIC COUNT IN DAVID LOW WAY NORTH OF HERON STREET 15.s.24.2 Page - 11