13.7 report title: traffic management mount · pdf filec:\documents and...

$: 13.7 REPORT TITLE: TRAFFIC MANAGEMENT MOUNT · PDF filec:\documents and settings\jrichter\local settings\temp\@iwd@@smiller-ceopa@@jrichter@\dpoddrop\46-050-010 cameron gawler mann$
c:\documents and settings\jrichter\local settings\temp\@iwd@@smiller-ceopa@@jrichter@\dpoddrop\46-050-010 camerongawler mann st roundabout update.doc

13.7 REPORT TITLE: TRAFFIC MANAGEMENT MOUNT BARKER CBD : GAWLER/MANN STREETS AND CAMERON ROAD (ROUNDABOUT)

DATE OF MEETING: 2 NOVEMBER 2009

AUTHOR: MATTHEW DAWKINS

AUTHOR’S TITLE: SENIOR PROJECT MANAGER -INFRASTRUCTURE

REPRESENTORS: NIL

FILE NUMBER: 46/050/010

ATTACHMENTS: 1. PRELIMINARY DESIGN2. TRANSIT-PLUS LETTER OF SUPPORT3. ARBORIST REPORT4. TREE REPLACEMENT PLAN

DEPARTMENT: INFRASTRUCTURE AND PROJECTS

DEPARTMENTMANAGER: BRIAN CLANCEY

PURPOSEReport progress and implications of the permanent roundabout design for the intersection of Gawler/Mann Streets and Cameron Road and seek approval to proceed with the project.

RECOMMENDATIONThat Council:

1. Approve the preliminary design for a permanent roundabout at the intersection of Gawler/Mann Streets and Cameron Road as presented as Attachment 1 with a view to progressing the design to a finalised design for construction via a tendering process in accordance with Council’s Procurement Policy.

2. Approve the removal of the two (2) non-significant treesshown in the arborist report (Attachment 3).

3. Approve staff making development application for the removalof the one significant tree shown in the arborist report (Attachment 3).

4. Approve the attached tree replacement plan comprising the planting of 21 new trees by Council (Attachment 4).

District Council of Mount Barker Council Agenda 2 November 2009 131


5. Note that a reference group will be established forthwith to consider construction timing and traffic control measures aimed at minimising disruption with a view to having input to the traffic management specification in the construction tenderdocuments.

6. Note that after a tendering process, there will be a subsequent report brought to Council summarising the tendering process outcome and project timing.

BACKGROUND

At its meeting of the 3rd of March 2008, Council noted the report on the planned construction of a temporary roundabout at this location and the need for a permanent roundabout to replace it at a later date. It was reported that :

The temporary roundabout will not address any drainage, pavement requirements, alignment of existing kerbing and impact of existing trees on traffic.

The construction of the temporary roundabout was completed in2008. In 2008/09, Council committed $90,000 towards theimplementation of the permanent roundabout together with receipt of an Auslink Blackspot Program allocation of $ 180,000 for an estimated project value of $270,000. After the procurement of designs, project management and investigations to the close of 2008/09, an allocation of $ 246,700 was brought forward to the Council’s 2009/10 budget after completion of the required land acquisition by Council.

DISCUSSION

The “design vehicles” for this location are the Controlled Access (CA) 14.5m non-articulated buses used by Transit-plus together with 19.0m semi-trailers that occasionally make deliveries to the larger CBD retail outlets. This greatly affects the roundabout geometry with respect to providing for the safe swept path of these large vehicles. Transit Plus have written a letter of support for the upgrading of the intersection. That letter is provided as Attachment 2 to this report.

The temporary roundabout at this location has improved traffic safety at this location largely by slowing traffic and providing the traffic calming that is afforded by a roundabout intersection treatment.

Design checks of the existing temporary roundabout geometry for the design vehicles described above show that in order to negotiate theintersection, these vehicles are required to travel with unacceptablytight clearances from roadside obstructions (eg trees and light poles)



and footpaths. As such, whilst formalising the temporary roundabout had been considered by staff, the current temporary geometry was found to not comply with the relevant design code for the legal use of roundabouts. Further, the temporary roundabout was established and approved on the basis that it would ultimately be replaced by a permanent and design standard compliant roundabout.

Attachment 1 to this report presents the preliminary roundabout design which is proposed to be progressed to a finalised detailed design suitable for construction. This design has been prepared through careful design consideration by Councils consulting engineer (Wallbridge and Gilbert) to firstly ensure compliance with the relevant design code and secondly minimise impact on the surrounding environment. The preliminary design has also been reviewed byMurray F Young and Associates (MFY), Transport Engineering consultants.

MFY were briefed to review the design from a technical perspective and specifically to assess whether there were opportunities to preserve the three trees that are located close to the intersection. In regard to the latter, MFY have concluded that retention of the threetrees would prevent the development of a compliant design and alsowould present both collision risks and sight distance obstructions.

The preliminary design presented with this report satisfies the current 14.5m CA bus routes in use. Within the currently available road reserve, the geometric design has been developed and refined to also accommodate some of the possible future 14.5m CA bus movements.

POLICY IMPLICATIONS1. Financial/budgetAs discussed, Council has been successful in obtaining $ 180,000 in funding through the Black Spot program to construct a permanent roundabout and have recently acquired a corner cut off on the south eastern corner to facilitate Council infrastructure.

With a view to refining the overall project cost, investigations aimed at gaining improved knowledge of the geotechnical conditions, extent of existing road pavement quality and the affect the reconstruction works may have on existing underground services are underway.

The preliminary findings of these investigations indicate that underground services are generally deep enough to be unaffected by the construction of new road pavement. Further, there is a significant existing depth of road pavement which will potentially reduce the extent of pavement reconstruction required. These findings willgenerally have a favourable effect on the project cost. Theseinvestigations are continuing with the consulting engineer and it is proposed that upon completion of the detailed construction drawings,



a pre-tender estimate will be produced to assist in the assessment of the project cost. In the event that there is a significant change to the project estimate, project funding adjustments will be formalised through a subsequent report to Council and/or quarterly budget review process.

It should be noted that the allocation of Blackspot funding to this project has already been carried forward from 08/09 and it is understood that unless the Blackspot contribution is expended in 09/10, it will likely be lost.

2. Legal

Council has delegated powers through the Minister for Transport forthe installation, maintenance, alteration, operation, removal or display of any traffic control device, subject to conditions as outlined in the Instrument of General Approval issued by the Minister for Transport. A roundabout is such a device.

All traffic control devices used must conform to the requirements of the Road Traffic Act and associated Rules and Regulations. Also, all traffic control devices must conform to the requirements of, and be installed in accordance with, the provisions contained in the Code of Technical Requirements for the Legal Use of Traffic Control Devices.

As discussed above, the existing temporary device does not complywith the relevant design codes and hence it has been establishedthat there is a need to formalise a permanent and compliant roundabout at this location.

3. Staffing/Work Plans

The roundabout design is being undertaken by a consultant engineer suitably qualified in road design. Upon completion of the design, construction will be procured through an open tender process and besupervised by a Council nominated project manager.

4. Environmental

The intersection is in a built up area and the design requires the removal of three (3) large trees. The preliminary roundabout design(Attachment 1) presented with this report requires the removal of these trees based on:

• the requirement to accommodate the kerb alignments and associated swept paths of the large design vehicles described above,

• the requirement to create safe clear zones behind kerb-linesto avoid potential collisions with roadside obstacles and footpath areas, and



• the necessity to provide adequate and unimpeded sight lines for intersection users. This particularly applies to road users that must wait at hold lines and view right to give way.

The three trees in question have been recently assessed byCouncil’s arborist. The arborist’s report has been provided as Attachment 3. In summary, of the three trees, the tree adjacent to the Red Cross shop is classed as “significant” pursuant to the Development Act. Further, the report indicates that all three trees have been subjected to inappropriate pruning practices over the years and the structure of each tree has continuously declined due to the ingress and spread of wood decay fungi. Finally, the two non-significant trees have also been identified for removal as part of Council’s Mt Barker CBD Street Tree Masterplan which was adopted by Council in 2004.

It is requested that Council approves the removal of the two non-significant trees and further approves staff making developmentapplication to the relevant authority for the removal of the significant tree on the basis that all three trees present a significant obstruction to the design and implementation of the safety improvements that are required at this important CBD intersection.

Council’s Tree Management Policy requires tree replacement at a ratio of 6 to 1. In this case, a tree replacement plan (Attachment 4) has been produced which exceeds this ratio and proposes the planting of 21 trees in close proximity to the intersection. Whilst the replacement plan submitted draws some direction from the dated 2004 Street Tree Masterplan, given the age of that masterplan and the Town Centre Review project which is just commencing, the Street Tree Masterplan will be undergoing review and update inconjunction with advice from Council’s arborist.

5. Social

This road improvement represents a significant opportunity to make road safety improvements and will therefore contribute towards the improvement and safety of the road network within the DistrictCouncil of Mount Barker.

As the projects progresses to detailed design and specification, it is timely that a reference group is established forthwith to consider construction timing and traffic control measures aimed at minimising disruption with a view to having input to the traffic management specification in the construction tender documents. For example, some works could possibly be undertaken at night to ease the disruption to daytime traffic flows. The reference group will comprise representatives from Business Mt Barker, Gawler Street Traders, SAPOL, TransitPlus and Council staff.



Indications are that a simpler construction method will likely be able to be applied to speed up the construction process however there may still be the need to consider some of the works being carried out at night under construction lighting. This will aim.

It is anticipated that construction could commence in early 2010. Themajority of construction work in roadways is expected to becompleted in approximately 6 to 10 weeks subject to the final extent of service alterations (if any) and pavement rehabilitation determined from the ongoing investigations described above.

6. Strategic Plans

The following extract from Council’s Strategic plan applies:

Lifestyle – “Council will support and encourage a well-planned district that provides for the needs of the community, enhances the quality of life, and is safe and accessible for all”

The draft Transport Master Plan has been through community consultation and identifies the importance of this project. The TMP is intended to be brought to Council for adoption at the 7 December 2009 Council meeting.

COMMUNITY CONSULTATION

1. Customer Needs Analysis

The customers who will be directly affected are the motorists who traverse these roads and local businesses. Advance warning signage will be used to inform the community to expect delays and of any changes to traffic conditions needed as part of the construction works.

2. Promotion/Communications

The community will be made aware through various channels in accordance with Council’s Community Consultation process. This will include appropriate advance warning signage prior to construction work commencing.

The local business community will be engaged through the aforementioned reference group (recommendation 5) with a view to reviewing, informing and communicating the timing of construction activities and work durations.


ITEM 13.7 ATTACHMENT 1


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