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Technical Report - Traffic and Transport Assessment Addendum

May 2011

Mt Victoria to Cobham Drive Scoping Study - Technical Report – Addendum to Traffic and Transport Assessment

© NZ Transport Agency

www.nzta.govt.nz

May 2011

Revision D

ISBN

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Page i

Record of amendment

Report reviewed by:

Name Position Signed/approved Date

David Turner WTA Transport Leader 3/05/2011

Tim Kelly External peer review 13/04/2011

Wayne Stewart External peer review 18/04/2011

Report approved by:

Name Position Signed/approved Date

David Turner WTA Transport Leader 03/05/2011

Chris Purchas WTA Duplication study lead 05/05/2011

Details of Revision

Amendment

number

Description of change Effective date Updated by

A Draft Issue 09/03/2011 GN

B Issued for external review 22/03/2011 GN

C Revised following comments from peer review 03/05/2011 GN

D Revised following edit 27/05/2011 GN

Page ii


May 2011

Contents

Executive summary ..................................................................................................................................................................................... 1

1 Introduction ......................................................................................................................................................................... 3

2 Design philosophy changes ...................................................................................................................................... 4

3 Refinement of options .................................................................................................................................................. 6

3.1 Tunnel alignment options .............................................................................................................. 8

3.2 Ruahine Street alignment ............................................................................................................. 10

3.3 Wellington Road alignment .......................................................................................................... 12

3.4 Intersection options ...................................................................................................................... 14

3.5 Cost estimation ............................................................................................................................. 15

3.6 Preferred option identification ..................................................................................................... 16

4 Land use ............................................................................................................................................................................... 18

5 Option description ........................................................................................................................................................ 21

5.1 ‘Do Minimum’ ............................................................................................................................... 21

5.2 Option ........................................................................................................................................... 22

5.3 Accommodating alternative views and approaches .................................................................... 24

5.4 Reflecting principles in the preferred option .............................................................................. 27

6 Traffic analysis ................................................................................................................................................................ 33

6.1 2009 base ..................................................................................................................................... 33

6.2 2026 ‘Do Minimum’ and Tunnels Alliance option ...................................................................... 39

7 Transport economics ................................................................................................................................................... 53

8 Further investigation ................................................................................................................................................... 56

Executive summary

The Wellington Tunnels Alliance (WTA) has been commissioned by the NZ Transport Agency (NZTA) to

undertake a study and report on alignments for the duplication of the Mt Victoria Tunnel as part of the

wider Roads of National Significance (RoNS) projects covering the Wellington Northern Corridor.

As part of the initial scoping report stage, a long list of route alignment options has been developed and

investigated. Each alignment option has been evaluated against a predetermined multiple criteria

framework which reflected both the higher level RoNS Northern Corridor and project specific objectives.

The RoNS objectives for the Mt Victoria to Cobham Drive corridor include improving access into and

around the Wellington central business district (CBD), and improving route security, as well as improving

access to the airport, the eastern suburbs and the regional hospital. The overriding study objectives

include:

• To keep the State Highway functioning effectively up to and including 2026 (based on high growth

traffic predictions); and

• To maintain or enhance the function of the surrounding area (connectivity with local road

network, public transport, pedestrians, cyclists and recreation including the various activities in

the Town Belt).

This addendum to the traffic report provides an updated assessment of the corridor from a traffic and

transport perspective and should be read in conjunction with the technical report: Traffic and Transport

Assessment1. Since the initial issue of this report, updated data and more detailed information regarding

road alignment, demand forecasts, environmental and statutory constraints, urban design principles and

costings have become available.

Following the development of a long list of options, each option was assessed using a Multiple Criteria

Assessment (MCA) tool as a coarse screening process. More details of the option evaluation process can

be seen in the Evaluation Framework technical report2. The long list of options was narrowed down to a

short list of three options consisting of:

1) A northern duplicate tunnel with at grade intersection treatment

2) A southern duplicate tunnel with at grade intersection treatment

3) A single bore diagonal tunnel with at grade intersection treatment.

Following a further refinement to the MCA process, additional information from urban design specialists,

environment experts and updated cost estimates have allowed further refinement of the option evaluation

process. This addendum has focused on the northern and southern duplicate tunnel alignments. From a

traffic modelling perspective these two options are similar.

1 Mount Victoria to Cobham Drive Scoping Study – Technical Report –Traffic and Transport Assessment.

2 Mount Victoria to Cobham Drive Scoping Study – Technical Report – Evaluation Framework


May 2011

Further assessment has been carried out on the Ruahine Street and Wellington Road alignments, using the

MCAT process. Information and input from technical experts has led to further detail being developed for

the parallel tunnels regarding the removal of parking, pedestrian and cycle treatment through the tunnel

and corridor, access of vehicles from adjoining properties, the landscaping of cuts and the treatment of

the portals.

Updated demands from the Wellington Saturn model have been received after a decision was made to

adopt the high growth regional land use scenario as an assumption to the modelling. Intersection

modelling through the corridor has been updated with these demands.

The Option which has been modelled includes the provision of a parallel tunnel, with capacity

improvements (a mixture of 2/3 lanes in each direction) through the Ruahine Street and Wellington Road

corridor. The performance of the intersections through the corridor still shows issues surrounding

capacity and level of service as experienced with the ‘Do Minimum’ scenario and present situation. In the

‘Do Minimum’ and (to a lesser extent) the existing situation, the limited capacity of the corridor results in

large proportions of vehicles, which would ordinarily make use of the State Highway, rerouting along

alternative routes. The improved capacity of the corridor in the Tunnels Alliance Option results in large

proportions of this traffic returning to the State Highway corridor. This removes traffic from local roads

and supports the intended hierarchy of the road network producing network-wide benefits.


May 2011

1 Introduction

The Wellington Tunnels Alliance (WTA) has been commissioned by the NZ Transport Agency (NZTA) to

refurbish the Mt Victoria and Terrace Tunnels to improve public safety and the operational life of the

tunnels’ infrastructure.

As part of the investigations of options for the refurbishment of the Mt Victoria Tunnel, it was identified

that increased safety might be achieved (in part) by providing egress cross passages from the road tunnel

to a new parallel tunnel, in the event of a major incident (e.g. fire) in the tunnel. A secondary advantage of

a new parallel tunnel is that the user experience for pedestrians and cyclists could be improved by a new,

wider passageway, not subject to the fumes and noise from vehicles as experienced within the current

tunnel.

In May 2010 the NZTA Value Assurance Committee (VAC) asked the WTA to check that the proposed

location for a future pedestrian/cyclist tunnel did not prejudice the optimum location of a future tunnel

from Mt Victoria to Hataitai, understood to be a “10-year horizon” project under the RoNS (Roads of

National Significance). Subsequent to this request, in June 2010 WTA was asked to undertake a study and

report on alignments for the Mt Victoria to Cobham Drive corridor, such that statutory approvals under an

EPA process could be obtained in the future as part of a wider designation of an upgraded road corridor

from the Terrace Tunnel to the airport.

The scoping stage of Mt Victoria to Cobham Drive study has largely been completed with the following key

activities having been carried out in the past months:

• Review existing information

• Develop consenting strategy

• Develop stakeholders/communications plan

• “Blue Skies” assessment of options

• High level technical assessments

• MCA coarse screening.

The scoping study has seen the development of a number of technical reports from the various technical

specialists intended as supporting documentation to an overarching Scoping Report. The Traffic and

Transport Assessment technical report outlined key issues within the study area, provided an operational

evaluation of the corridor using the available data at the time and developed a long list of options from a

traffic and transport perspective. Since the issue of this report, updated data and more detailed

information regarding road alignment, demand forecasts, environmental and statutory constraints, urban

design principles and costings have become available.


May 2011

This document serves as an addendum to the technical traffic and transport report3. It is intended to be

read with the traffic report as supporting technical documents to a Scoping Report.

2 Design philosophy changes

Since the initial scoping stage of the Mt Victoria to Cobham Drive study, we have updated the design

philosophy through the corridor to reflect:

• The project aims for level of service (LOS) within the corridor have been changed to acknowledge

that LOS (C/D) may not be a reasonable or practical target within an urban area. A LOS (E) is

considered appropriate at urban intersections.

• The desired design speed of the route was decided to be 60km/h which provides a natural

transition between 50km/h at the Basin Reserve and 70km/h at Cobham Drive. This still requires

ratification by the Value Assurance Committee (VAC).

A comparison of traffic engineering and geometric design standards from Austroads4 and the State

Highway Geometric Design Manual5 standards have been listed in Table 2-1. Standards which have been

adopted in the design of the Mt Victoria to Cobham Drive project have been highlighted in yellow. Local

roading standards from Wellington City Council have been used when considering the treatment of

changes to the local roads.

3 Wellington Tunnels Alliance, December 2010. Mt Victoria to Cobham Drive Scoping Study – Technical Report – Traffic

and Transport Assessment and Evaluation.

4 Austroads, 2010. Guide to Road Design. Part 3: Geometric Design and Part 4: Intersections and crossings: General.

Third edition, October 2010.

5 NZ Transport Agency, 2000. The State Highway Geometric Design Manual. Draft version, 1 December 2000.


May 2011

Table 2-1: Comparison of

Design Standards Design

Parameter

Austroads SHGDM

50km/h

design

speed

value

60km/h

design

speed

value

Reference

50km/h

design

speed

value

60km/h

design

speed

value

Reference

Reaction Time (Rt)

2.0 secs

Table 5.2

2.0 Secs

2.9.2

(Part 3)

Coefficient of Deceleration 0.36 0.36

Table 5.3

(Part 3) 52% 0.48

2.9.2 (ii)

Stopping Sight Distance

(SSD) 55m 73m

Table 5.4

(Part 3) 50m 65m

Table 2.12

Maximum Grade (over long

lengths of road) 6-8%

Table 8.3 6 – 8%

Table 5.2

Crest Curve (midblock) K

value 6.8 11.8

Table 8.7

(Part 3)

Crest Curve (intersection) K

value 24 13.8

Table 3.1

(part 4 A)

Sag Curve K Value Comfort

and Headlight sight

distance

min 4 min 6

Figure 8.7

(Part 3) Min 6

Table 5.4

Side Friction 0.33 0.35

Table 5.3 0.222

Table 2.8

Superelevation

Max 5%

Table 7.7

8%

(83m

radius at

60kph)

2.8

Superelevation Rotation

Rate 3.50%

Section

7.7.6 (Part

3)

2.50%

Table 2.9

Adverse Cross fall -3%

Minimum Radii 130m 200m

Table 7.10

(Part 3) 550m 800m

Table 2.7

Intersection Advanced

Sight Distance (ASD) 55m 73m

Part 4A

Table 3.1

K min 13.8 K min 24

Minimum Radius (m)

Radius

90m

Radius

130m

Figure 4.16

Minimum lane width (m)

3.3m for

through

lanes

Section

4.2.5 (Part

3)

Items which have been adopted in Tunnels Alliance Design


May 2011

3 Refinement of options

Following the ‘Blue Skies’ option workshop, a long list of corridor options was identified. An assessment

was performed on the long list of options using a Multiple Criteria Assessment (MCA) tool. This process

has led to the identification of a short list of three alignment options to be taken forward to the next stage

of the study. More information on the MCA process and details of the assessment of options can be found

in the Evaluation Framework technical report6. The process has been represented graphically in the Figure

below. Options 3A and 3B (northern and southern duplicate tunnels) and Option 5 (single directional

diagonal tunnel) were identified as the preferred short listed options (stage 2 on the figure below).

6 Mount Victoria to Cobham Drive Scoping Study – Technical Report: Evaluation Framework


May 2011

Option for public engagement

Workshop with VAC, NZTA Initial Cost Estimates

Sta

ge

2: T

un

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l

Sh

ort

Lis

t

Sta

ge

4:

Pre

ferr

ed

Op

tio

n

Sta

ge

1: Tu

nn

el Lo

ng L

ist

50

Op

tio

ns

12

Op

tio

ns

3 O

pti

on

s1

Op

tio

n

Blue Skies Optioneering and

develoment of Long List

Evaluation Framework

Development (MCA tool)

Practicality AssessmentLong List Option Evaluation

Refined Option Evaluation Updated Cost Estimate

Ruahine St/Wellington Rd

Option Evaluation

Sta

ge

3:

Ro

ad

Op

ion

s

Workshop with VAC and NZTA

Figure 3-1: Scoping Study Option Evaluation Process

As the scoping stage progressed, initial cost estimates were provided for the options. Option 5 was

identified to involve a substantial cost disadvantage over Options 3A and 3B. Although the initial cost

estimates are subject to review, Option 5 is expected to attract a 30% cost disadvantage over the Northern

Duplicate tunnel.

Grade separation of the Ruahine Street and Wellington Road corridor for Options 3A and 3B were also

costed. The grade separation of the Ruahine and Wellington Road corridor involved another 13% of the at

grade cost. Grade separation of the State Highway corridor was deemed to be too expensive and not

considered appropriate given the context of the corridor.


May 2011

While the ability of Option 5 (Diagonal single directional tunnel) to relieve land take on Ruahine Street and

reduce effects for Hataitai residents was appreciated by the assessors (NZTA board, DMT, VAC), the

additional benefits associated with this option did not warrant the significant increase in cost over a

parallel duplicate tunnel. Issues around connectively for Hataitai residents due to the formation of one-way

roads, additional travel distance and the difficulty in providing a convenient and desirable pedestrian and

cycle facility were also considered. It was also highlighted that the duplicate tunnel would pose some

significant visual issues and was too remote from the existing Mt Victoria Tunnel to provide for

connectivity in case of emergency access. The diagonal tunnel was dropped as a preferred option.

From a traffic and transport perspective, the analysis of the corridor has been focused on the Northern

Duplicate (3A-1) and Southern Duplicate (Option 3B-1) tunnel options with at grade intersection treatment.

Both options are discussed in more detail to highlight land take, traffic operations, position of tunnel

portals, ability to support cycle routes and cost of options.

Both of the preferred tunnel alignments require widening of the existing State Highway over the length of

Ruahine Street and Wellington Road. The options regarding on which side the widening will occur are

assessed in more detail to provide input into the evaluation process. The effects of these options are

accessed from a connectivity and operation perspective.

3.1 Tunnel alignment options

3.1.1 Northern duplicate tunnel

The northern duplicate tunnel will be positioned approximately 25m, or 1.5 times the duplicate tunnel

diameter, north of the existing tunnel running parallel at a similar level to enable egress passage to be

made between it and the existing tunnel.

Land take

The land take associated with the northern tunnel involves a significant impact on the northern side of

Paterson Street. Some of these properties are currently owned by NZTA, but selected properties will need

to be acquired. Two buildings are listed as heritage buildings and will require special consideration. The

number of other buildings which qualify for the pre-1930s demolition rule and require consent to

demolish will need to be assessed.

On the eastern side of the tunnel, land will be required for the portal. This will involve the acquisition of

the Hataitai Kindergarten on Taurima Street but is unlikely to include any further property take.

Traffic operations

The northern duplicate tunnel means connection to Taurima Street is more difficult to provide. Due to the

alignment of the northern tunnel, the development of the left turn slip lane may require widening of the

tunnel bore. Alternative arrangements are currently being explored which do not require widening of the

tunnel bore. Right turns out of Taurima Street east will be banned. This allows selected access to the


May 2011

Hataitai town centre and suburb. Full turning access is provided at the downstream Goa Street

intersection. The option maintains Taurima Street as the natural gateway to Hataitai, but creates potential

problems for pedestrians and cyclists wanting to cross Taurima Street.

Position of portals

The position of the western portal may to be in line with the existing tunnel portal, depending on final

design levels with approximately 25m of offset between the two. This means significant land take is

required to create the cut necessary to construct a portal in this position. The duplicate tunnel will be

constructed at a similar level to the existing tunnel; this will enable convenient egress to be provided

between the two tunnels.

The Eastern tunnel portal is proposed to be positioned approximately 20m to the north of the intersection

between Taurima Street and Ruahine Street. The level of the eastern portal is designed at around 1.5m

below the level of Taurima Street at this point. This will enable a smoother vertical profile of the road as it

tracks around the bend into Ruahine Street.

Cycle/pedestrians

It is proposed to include a shared pedestrian/cycle path within the duplicate northern tunnel. The

pedestrian/cycle path will be positioned on the northern side of the tunnel with connections to Paterson

Street and Taurima Street in a similar format to the existing situation.

3.1.2 Southern duplicate tunnel

Land take

The land take associated with the southern tunnel involves a significant impact on the southern side of

Paterson Street. Property on the southern side of Paterson Street is occupied by Wellington College and

Wellington East Girls College. The land required to construct the southern tunnel would involve

demolishing the schools tennis courts and a portion of the school playing fields.

At the eastern end of the tunnel, permanent land take will be isolated to town belt land. Temporary areas

are likely to be required to enable construction of the portal. The netball court on the north-east side of

Hataitai park complex, and the access road which links up to the Velodrome parking area with the exit

road from Hataitai Park, are likely to be affected and will require reinstatement after the tunnel

construction is completed. Significant disruption to the netball courts and velodrome is likely during the

construction period.

Traffic operations

The southern duplicate tunnel retains the existing left turn into Taurima Street at the Taurima

Street/Ruahine Road intersection. Right turns into and out of Taurima Street east will be banned. Full

turning access is provided at the downstream Goa Street intersection.


May 2011

Connection to the Basin Reserve scheme will involve use of Paterson Street, similar to the existing

situation. The west-bound traffic will use the proposed elevated structure while east-bound traffic would

follow Vivian Street and Kent Terrace connecting to the existing tunnel.

Position of portals

The western portal is proposed to be positioned to the east of the Wellington College tennis courts. The

Wellington East Girls College access road which connects to Paterson Road will need to be removed during

construction and reinstated following completion of the tunnel portal.

The eastern portal of the tunnel is positioned about 20m east of the north east corner of the Hataitai

sports complex (netball courts). The level will be considerably lower than the netball courts and will be

similar to the present Ruahine Street levels at this point.

Cycle/pedestrians

Pedestrians and cyclists would be provided for on the northern side within the southern duplicate tunnel.

Due to the position of the tunnel’s pedestrian/cyclist facility, pedestrians and cyclists would be positioned

between east-bound and west-bound State Highway traffic. This complicates the treatment at either end of

the tunnel.

At the Basin Reserve side, pedestrians and cyclists wanting to head in a northerly direction or towards the

CBD would need to cross the east-bound State Highway traffic. This could be achieved by a subway linking

the west-bound tunnel with the pedestrian facilities on Paterson Street or by providing a pedestrian link

between the two alignments at the Basin Reserve end of the tunnel.

At the eastern end of the Mt Victoria Tunnel, pedestrians and cyclists would need to cross from the

eastern side of Ruahine Street or from Taurima Street over the east-bound State Highway traffic and into

the eastern portal of the tunnel. This will likely take place at a grade separated structure similar to the

existing elevated structure which provides pedestrian access to Hataitai Park. An at-grade crossing of

Taurima Street would also be provided.

3.2 Ruahine Street alignment

3.2.1 Widening to the west (Town Belt Land)

Land take

Along the length of Ruahine Street, widening is proposed to occur in the Town Belt land on the western

side. Property boundaries on the eastern side of Ruahine Street will remain as is for the most part.

Selected properties at the southern end of Ruahine Street will be required in the realignment of the

Ruahine Street/Wellington Road corner. The Badminton Hall on the western side of Ruahine Street will

need to be removed.


May 2011

The corner of Wellington Road and Ruahine Street is proposed to be realigned to accommodate a

signalised intersection and improved sight distances and a more appropriate design speed. In order to

achieve this, a large portion of the property on the north-eastern corner of the intersection will be

acquired, along with most of the property on the southern side of Wellington Road to the Kilbirnie

Crescent intersection.

Traffic operations

The proposed scheme identifies the following intersections to be signalised:

• Goa Street/Ruahine Street

• Moxham Avenue/Goa Street

• Wellington Road/Ruahine Street

All movements at the Taurima Street/Ruahine Street intersection will be removed except the left in

movement from Taurima Street west approach.

If Goa Street/Ruahine Street is signalised, Goa Street/Moxham Avenue will also need to be signalised due

to its close proximity. Modelling indicates that stacking space on the link between Moxham Avenue/Goa

Street and Goa Street/Ruahine Street is critical, requiring co-ordination between the signals to ensure the

queues can be accommodated during peak periods. This becomes of increasing significance as

movements at the Taurima Street intersection are reduced. Goa Street, with all movements retained,

becomes a more significant intersection for access to Hataitai.

Cycle/pedestrians

The cycling and walking routes along the Ruahine Street corridor are proposed alongside the highway with

a shared accessway which will cater for pedestrians, cyclist and limited vehicle movements. This would be

positioned on the eastern side of Ruahine Street. The path requires an additional 6m of width to the road

reserve for the majority of the corridor length. Vehicular access will be given to those wishing to gain

access to a property on Ruahine Street which previously had access to the State Highway and has

subsequently been removed as part of the upgrades. Signalised crossing points would be provided at each

of the signalised intersections to help such access vehicles and pedestrians/cyclists to cross or enter the

local road network.

3.2.2 Widening to the East (Residential Land)

Land take

Under this option, widening would occur mostly on the eastern side of Ruahine Street. The designation on

the western side of Ruahine Street would be utilised but not to its full extent. Widening on the eastern side

means a full row of property on the eastern edge of Ruahine Street would be required. This is estimated to

include approximately 40 houses.

This option requires land currently occupied by the Church of Jesus Christ of Latter Day Saints. This option

does not affect the Badminton Hall and will allow its retention.


May 2011

At the Wellington Road/Ruahine Street intersection, realignment of the road means a significant number of

properties will be required to complete the widening works. The eastern alignment means the effect on

property is larger than with a western alignment requiring additional property on the north-east corner of

Wellington Road/Ruahine Street intersection.

Traffic operations

Operation of the eastern alignment is similar to the western alignment with signalised intersections at the

following locations:

• Goa Street/Ruahine Street

• Moxham Avenue/Goa Street

• Wellington Road/Ruahine Street.

All movements at the Taurima Street/Ruahine Street intersection will be removed except the left in

movement from Taurima Street west approach.

The link between the Goa Street/Ruahine Street and Moxham Road/Goa Street intersections is shortened

with an eastern alignment on Ruahine Street. The length of link is reduced to around 40m. This creates a

safety concern around the operation of the two consecutive intersections if operated in isolation. Co-

ordination of these intersections would be required, which would introduce additional delay to the Goa

Street/Wellington Road intersection.

Cycle/pedestrians

The cycling and walking routes along the Ruahine Street corridor are proposed alongside the highway on a

shared accessway which will cater for pedestrians, cyclist and limited vehicle movements. This would be

positioned on the eastern side of Ruahine Street. The path requires an additional 6m of width to the road

reserve for the majority of the corridor length. Vehicle access will be given to those wishing to gain access

to a property on Ruahine Street which previously had access to the State Highway and has subsequently

been removed as part of the upgrades. Signalised crossing points would be provided at each of the

signalised intersections.

3.3 Wellington Road alignment

3.3.1 Widening to the south

Land take

East of the Kilbirnie intersection, widening will occur on the southern side of Wellington road within

Kilbirnie Park. A designation currently exists on the southern side of Wellington Road between the

Wellington Road/Ruahine Street intersection and the Kilbirnie Crescent/Wellington Road intersection. The

majority of widening for this section would occur on the southern side within the designated property but

would require more width than the designation provides. A number of properties on the northern side of

Wellington road would also be required as a result of the curve realignment. East of the Kilbirnie


May 2011

Crescent/Wellington Road intersection, a width of approximately 10m is required from the Kilbirnie Park

sports field. The works are likely to affect the clubhouse on the northwest corner of Kilbirnie Park. This

will require the relocation of this building.

Widening will have a small effect on the Saint Patrick’s College site on the south-east corner of the

Cobham Drive/Evans Bay Parade with the need to acquire a sliver of land behind the existing southern

footprint.

Traffic operations

The intersections at Kilbirnie Crescent/Wellington Road and Cobham Drive/Evans Bay Parade are already

signalised but will be widened to accommodate additional future demand. Under the preferred option,

additional through lanes are added to both intersections. On the eastern approach to the Kilbirnie

Crescent/Wellington Road intersection, the left turn slip lane has been removed to reduce the impact on

land take at Kilbirnie Park.

Moxham Avenue and Walmer Street currently connect to the State Highway through priority controlled

intersections. These connections will be closed, with access for properties with current frontage on the

State Highway provided via access lanes.

Cycle/pedestrians

Pedestrians and cyclists will be accommodated on the northern side of Wellington Road on a shared 6m

wide access-way. This access-way will provide for pedestrians cyclists and limited vehicle access to

property. The shared access-way will provide continuity of an off road pedestrian cyclist facility from

Cobham Drive through to the western portal of the Mount Victoria Tunnel.

Signalised crossing points will be provided at the Kilbirnie Crescent/Wellington Road and Cobham

Drive/Evans Bay Parade intersections.

3.3.2 Widening to the north

Land take

Widening to the north of Wellington Road increases the property requirement on the Wellington

Street/Ruahine Street corner. Selected property on the southern side of Wellington Road directly to the

west of the Wellington Road/Kilbirnie intersection will still be required to upgrade the intersection.

Between the Kilbirnie/Wellington Road and Cobham Drive/Evans Bay Parade intersections, an entire row of

property on the northern side of Wellington Road will be required. This does, however, mean that no

effects are felt on Kilbirnie Park and St Patrick’s College.

Traffic operations

Traffic operations remain similar to the southern option. The signalised intersections at Kilbirnie

Crescent/Wellington Road and Cobham Drive/Evans Bay Parade will be widened to accommodate

additional through lanes on the State Highway approaches. On the eastern approach to the Kilbirnie


May 2011

Crescent/Wellington Road intersection, the left turn slip lane has been removed to reduce the footprint.

The left turn slip lane on the west approach to the Evans Bay Parade/Cobham Drive intersection is changed

to a left turning lane to better facilitate the pedestrian and cyclist crossing.

Moxham Avenue and Walmer Street currently connect to the State Highway with priority controlled

intersections. These connections will be shut, with access for properties with current frontage on the State

Highway provided via access lanes.

Cycle/pedestrians

Pedestrians and cyclists will be accommodated on the northern side of Wellington Road on a shared 6m

wide access-way. This access-way will provide for pedestrians, cyclists and limited vehicle access to

property.

Signalised crossing points will be provided at the Kilbirnie Crescent/Wellington Road and Cobham

Drive/Evans Bay Parade intersections.

3.4 Intersection options

A number of intersection options have been considered. These options have been modelled and assessed

from a safety and operational perspective. While these options are not evaluated using the MCA

framework, preference has been based on the most effective operation from a traffic engineering

perspective.

3.4.1 Wellington Road/Ruahine Street

Two options for the treatment of the Wellington Road/Ruahine Street intersection have been considered.

The options which have been considered include:

� Signalised intersection: The intersection would form a signalised T junction. The radius of the

Ruahine Street to Wellington Road curve would need to be realigned to provide adequate stopping

sight distance at the intersection. Pedestrian crossing would be provided on the Wellington Road

south and Ruahine Street approaches. The Wellington Road south approach would consist of dual

right turn lanes and a left turn lane. The Wellington Road eastern approach would have three through

lanes and a left turn slip lane. The Ruahine Street approach would have two through lanes and a right

turn lane.

� Left in Left out. An alternative option is to restrict access to Wellington Road south to left in left out

only. This removes the need to provide three through lanes in the northern direction. The left turn

from Wellington South into Ruahine Street will form a continuous movement resulting in Ruahine

Street gaining a third north-bound lane north of the Wellington Road intersection. The Wellington

Road South approach will consist of a left lane only, while the Ruahine Street approach has two

through lanes. The Wellington east approach has two through lanes and a free left lane.


May 2011

3.4.2 Taurima Street/Ruahine Street

The Taurima Street/Ruahine Street intersection has been identified as a crash black spot in the present

situation. The operation of the intersection is under pressure in the existing situation with frequent

queuing and delays associated with the Taurima Street east approach. Two options have been identified

for the treatment of the intersection:

� Closing Taurima Street completely

� Left in connection to Taurima Street: A diverge lane will begin immediately east of the eastern tunnel

portal and feed into Taurima Street. All other movements at the intersections will be banned for

safety reasons.

3.5 Cost estimation

Initial expected cost estimates were developed as part of the scoping stage of the study. The initial

costing exercise has led to costs being assigned to each of the long list options. A selection of expected

costs is given below in Table 3-1. These cost estimates were used to assess options in the initial MCA

process. More details on initial expected costs are included in the Cost Estimate technical report.7

Table 3-1: Initial expected costs for long list options

Option Description Total Expected

Option Cost

($Million)

0-0 Do Minimum $17

3A-1 New tunnel parallel and to the north of the existing tunnel, with all

other intersections along Ruahine/Wellington at grade with signals $4308

3A-2 New tunnel parallel and to the north of the existing tunnel with all

other intersections grade separated through elevating the main

carriageway at key intersection locations

$495

3B-1 New tunnel parallel and to the south of the existing tunnel with all

other junctions along Ruahine/Wellington at grade with signals $480

4A-1 New twin bore tunnel from Paterson Street to Wellington Road/

Ruahine Street corner with all other intersections along Wellington

at grade with signals

$827

5A-1 New single bore two lane tunnel from Paterson Street to Wellington

Road with Wellington Road intersections at grade with signals $593

7 Mount Victoria to Cobham Drive Scoping Study: Technical Report: Cost Estimates. 8 Costs for Options 3A-1 and 3A-2 have been adjusted following changes to the length of tunnel bore. This is detailed

in the Mt Victoria to Cobham Drive Technical Report: Cost Estimate


May 2011

The initial cost estimate indicates that options 3A-1 and 3B-1 represent the most cost-effective solutions

and were similar in expected cost (around 10%). Option 3A-2 (Parallel tunnel with grade separated

intersection treatment) attracts an additional $65M to the total cost over the at grade solution. The twin

bore diagonal tunnel option was almost double the cost of the parallel tunnel. The single directional

diagonal tunnel attracted around 40% additional total cost over the parallel tunnel options.

Following the development of a preferred option short list, a more detailed assessment of the route

alignment and environmental effects was undertaken. The cost estimate for the preferred option has been

calculated using the NZTA Cost Estimation Manual (SM014). This preferred solution includes the

identification of two possible tunnel options including a Northern and Southern duplicate tunnel. For the

option, the remainder of the route has been adopted as consistent with:

• At grade construction along Ruahine Street through widening the existing route, with a signalised

intersection at Goa Street.

• At grade construction between Ruahine Street and Wellington Road adopting a 60k/ph design speed

through this route.

• At grade intersections along Wellington Road at Kilbirnie Crescent and Evans Bay Parade/Cobham

Drive.

Table 3-2 shows the updated cost estimate which has been prepared following the scoping stage of the Mt

Victoria to Cobham Drive study. More detailed information available at the time of the revised estimate led

to the length of the northern tunnel option (Option 3A-1) reducing. Internal peer review of the schedule of

costs assumed was also carried out. More details on the cost estimate can be found in the Cost Estimate

Technical Report9.

Table 3-2: Updated cost estimate

Option Base Cost Expected Estimate 95%ile Cost

Preferred Option $339.4 M $430.3 M $492.8.0 M

3.6 Preferred option identification

Further refinement of the short list of alignment options has led to a preferred option being identified.

The MCA assessment of the north and south tunnel has been updated with regard to the more detailed

information on route alignment, land impact, environmental assessment, cost estimation and urban

design. The main points of difference influencing the decision were:

9 Mount Victoria to Cobham Drive Scoping study: Technical report: Cost Estimate


May 2011

� Cost: Following refinements to the alignments, the length of the northern tunnel has been updated to

680m while the southern tunnel is 835m. The tunnelling cost is a significant proportion of the overall

cost making the northern tunnel approximately 10% ($50m) cheaper in total costs.

� Land impact: Northern tunnel impacts approximately 12 properties on Paterson Street and the crèche

on Taurima Street, while the southern tunnel impacts a number of schools and Hataitai Park sports

facilities.

� Pedestrian and cycle connection: Northern tunnel provides for desire lines better than southern

tunnel which requires grade separated treatment at either end of the tunnel.


May 2011

4 Land use

In January 2011 a workshop was held between key decision-makers from the Wellington City Council,

Greater Wellington Regional Council (GW), the New Zealand Transport Agency, OPUS consultants and the

WTA. Discussions revolved around the land use assumptions and inputs in the Wellington Strategic

Transport model (WTSM) and other Wellington models.

The meeting aimed to establish immediate requirements for land-use planning in the assessment of RoNS

projects, such as the Mt Victoria Tunnel and the Basin Reserve project. From an overall project perspective,

Greater Wellington Regional Council was keen to see the redistribution of trips within the region, rather

than additional trips being added to the network. It sees no new trips added to the model assuming that

all changes in population and employment patterns are shifts in population density within the current

maximum.

Mike Vincent produced a paper “WTSM Input Tracking 2009” in January 2010 and the conclusion from the

data was that “Regional population was tracking between our medium and high growth forecast, with

Wellington City/Upper Hutt/Carterton/South Wairarapa tracking towards the higher projections, Lower

Hutt/Porirua/Masterton tracking on or just above the medium, and Kapiti below the medium.” A proposal

was made to test the urban RoNS projects with the high growth forecast rather than the previously used

medium growth scenario.

Discussion around land use has led to the following assumptions:

• Airport: a reasonable growth level is assumed

• Kilbirnie growth spine: as previously forecast

• Rugby Street supermarket: included but will need to be updated following the latest developments

• Adelaide Road supermarket: assumptions as existing but to be updated

• Rongotai Big Box: Industrial development associated with airport included in 2016

• Miramar Growth: potential intensification excluded

• Indoor Community Sports Centre: included in 2016

• Johnsonville Mall: not included

• Newlands supermarket: not included

• Churton Park supermarket and school: not included.

The high growth forecast leads to a number of assumptions being made in the development of the

SATURN model. The trip matrices used for all the modelling (except the 2009 Base) are based on the high

growth trip matrices from WTSM. The high growth matrices are based on the following assumptions:

• Population increases 21% from 2006 by 2026 (compared to 12% for medium growth)

• Households increase 32% from 2006 by 2026 (23% for medium growth)

• Employment increases 30% from 2006 by 2026 (21% for medium growth)

• Real gross domestic product (GDP) per capita will grow by 2.1% per annum (1.8% for medium

growth).


May 2011

The revised land use (RLU) growth assumptions were used in the first iteration of the SATURN modelling.

The RLU assumed a medium growth scenario which had been revised to include specific land use activities

which had progressed since the original WTSM forecast. The demands for this scenario have been included

for comparison.

Naturally the high growth scenario translates to high levels of forecasted demand in 2026. Table 4-1

shows that high growth produces demands ranging from 6% to 46% higher than for the previous RLU

scenario and between 36% and 154% higher than 2009 validated demands.

Table 4-1: Comparison of SATURN model demand (PCU/h)

Intersection Approach 2009

Validated

model

2026

Revised

Land Use

(RLU)

2026 High

Growth -

Option

Tunnels

Alliance

%

increase

between

2009 and

2026

Tunnels

Alliance

%

increase

between

2026 RLU

and 2026

Tunnels

Alliance

Evans Bay/Cobham

Drive East am 1951 2304 2648 36% 15%

pm 1426 1779 2022 42% 14%

West am 1404 2088 2495 78% 19%

pm 1606 2574 2732 70% 6%

Kilbirnie Cres/ East am 1520 2371 2634 73% 11%

Hamilton Rd pm 1234 1918 2148 74% 12%

West am 1611 2068 2999 86% 45%

pm 1696 2633 3144 85% 19%

Wellington Rd/ East am 1583 2662 3484 120% 31%

Ruahine St pm 1547 2389 2577 67% 8%

North am 1640 1985 2889 76% 46%

pm 1589 2570 2940 85% 14%

Goa St/ North am 1603 2238 3186 99% 42%

Ruahine St pm 1598 2898 3363 110% 16%

South am 1416 2651 3590 154% 35%

pm 1429 2418 2835 98% 17%


May 2011

Intersection Approach 2009

Validated

model

2026

Revised

Land Use

(RLU)

2026 High

Growth -

Option

Tunnels

Alliance

%

increase

between

2009 and

2026

Tunnels

Alliance

%

increase

between

2026 RLU

and 2026

Tunnels

Alliance

Paterson Street East am 1676 2955 3791 126% 28%

pm 1473 2637 2998 104% 14%

West am 1725 2238 3186 85% 42%

pm 1808 2898 3365 86% 16% Notes:

1. Revised land use demands were used in the initial Traffic and Transport Assessment Report

2. Tunnel Alliance option demands have been used for reporting in the Addendum.

Both the Revised Land Use and High Growth scenario WTSM model runs assume the following

infrastructure improvements are implemented:

• No change to fuel prices

• State Highway 2 Dowse to Petone upgrade (2016)

• Public Transport rail extension to Waikanae (2016)

• Public Transport real time information (2016)

• SH1 Ngauranga to Aotea Quay Hard Shoulder Running (2016)

• Basin Reserve Grade Separation to Buckle Street (2016)

• Western Link Road stage 1 and 3 (2016)

• Peka Peka to Otaki expressway (2016)

• Terrace Tunnel duplication (2026)

• Mt Victoria Tunnel duplication (2026)

• Grenada to Petone 4 laning (2026)

• Transmission Gully (2026)

• Kapiti Expressway (2026)

• Otaki to Levin, Levin Bypass and north of Levin (2026).

The SATURN modelling has assumed the following changes to both the Option and ‘Do Minimum’

networks:

• Manners Mall bus lanes

• Kent Terrace/Cambridge Terrace bus lanes

• Adelaide Road bus lanes

• Golden Mile speed reduction

• Signalised pedestrian crossing at Courtenay Place with bus priority

• Adelaide Road/John Street improvement

• Signalise Hanson Street/John Street intersection


May 2011

• Signalise Constable Street/Owen Street intersection

• Signalise Constable Street/Coromandel Street intersection

• Signalise Riddiford Street/Hospital Entrance

• Signalise Riddiford Street/South of Hospital pedestrian crossing

• Signalise Mulgrave Street/Aitken Street intersection

• Troy Street/Cobham Drive roundabout improvemet;

• Ruahine Street and Wellington Road two lanes each direction as per WTA ‘Do Minimum’

• Basin Reserve grade separation as per Option A

• Tory Street and Taranaki Street widening

• Inner City Bypass widening; and

• Terrace Tunnel Duplication in 2026 only.

Under the current modelling methodology no consideration has been given to the effect the options have

on public transport patronage. This is an important consideration and the WTSM model will be

interrogated in more detail during the SAR phase of the project.

5 Option description

5.1 ‘Do Minimum’

The ‘Do Minimum’ scenario assumes no improvements to capacity through the tunnel would be offered.

This would result in the tunnel remaining as the key constraint through this section of the corridor. The

walking and cycling facilities within the existing tunnel would remain. Four lanes (two in each direction)

would be provided between Taurima Street and the Wellington Road/Kilbirnie Crescent intersection.

Traffic signals would be introduced at the following intersections:

� Goa Street/Ruahine Street. Localised widening at the intersection to include right turning

lanes on the Ruahine Street approaches. Two approach lanes on Goa Street.

� Goa Street/Moxham Avenue. Right turn lane added to the north approach.

� Wellington Road/Ruahine Street: Dual right turn lanes on Wellington Road west. Right turn

lane on Ruahine Street and left turn slip on Wellington Road south.

� Walmer Street/Wellington Road: Single lane approach on Walmer Street.

The majority of movements at the Taurima Street intersection are banned leaving a left in turn into

Taurima Street. The intersection between Wellington Road and Moxham Avenue is closed completely.


May 2011

5.2 Option

West of the Mt Victoria Tunnel, Paterson Street is currently two lanes in either direction. The duplication of

the tunnel will provide continuity of the two lanes in either direction to the eastern side of Mt Victoria. At

the Ruahine Street/Taurima Street intersection, a left turn slip lane from the State Highway into Taurima

Street will be provided. All other movements are banned. Shortly after the Ruahine Street/Taurima Street

intersection the road is proposed to flare out with an additional lane in either direction immediately north

of the Goa Street totalling six through lanes.

At the Goa Street intersection, additional right turn slots are provided on both the north and south

Ruahine Street approaches. Left turning traffic is provided for by a shared left/through lane on the

Ruahine Street south approach.

South of the Goa Street intersection the third lane on the south-bound side is dropped. At the Wellington

Road/Ruahine Street intersection, there are two through lanes in the east-bound direction and three in the

west-bound direction. The heavy right turn from Wellington Road south approach means an additional

right turn lane is needed.

Just to the east of the Wellington Road/Ruahine Street, a third lane is developed for east-bound traffic as it

approaches Kilbirnie Crescent/Wellington Road intersection.

The six lane arrangement is continued to the Cobham Drive intersection. To the east of the Cobham

Drive/Evans Bay Parade intersection the SH drops back to two lanes in each direction. A table of

intersection treatment under each of the modelled scenarios is outlined in Table 5-1.

Pedestrian and cycling facilities through the tunnel are proposed on the northern side of the duplicate

tunnel. Connection to Paterson Street will be provided from the western portal of the duplicate tunnel.

From here pedestrians and cyclists will have convenient access to the CBD via the facilities at the Basin

Reserve or Brougham Street.

On the eastern side of the tunnel, pedestrians and cyclists will emerge from the northern side of the

tunnel with the option to connect to Moxham Avenue via Taurima Street or travel parallel to the State

Highway on the proposed shared pedestrian/cycle/access-way which runs down the eastern side of

Ruahine Street and the northern side of Wellington Road.


May 2011

Table 5-1: Assumed intersection treatment

Intersection 2009 Existing Situation 2026 ‘Do Minimum’ 2026 Option

Taurima Street / Ruahine

Street

Priority intersection. All

movements allowed

except right turn into

Taurima East

Left in to Taurima Street only Left in to Taurima Street

only

Moxham Avenue / Goa

Street

Priority intersection, Goa

St approaches give way to

Moxham Ave

Signalised, additional right

turn lane on Moxham N

approach

Signalised, additional right

turn lane on Moxham N

approach

Goa Street / Ruahine

Street

Priority intersection. Goa

St approaches give way to

Ruahine St

Signalised. Ruahine St N

approach has RT lane, a

through lane and a shared

TH/LT lane. Ruahine St S

approach has RT lane, 2 TH

lanes and a LT slip lane. Goa

St has a RT lane and a shared

RT/TH/LT lane. Hataitai Park

has a RT lane and shared

TH/LT lane

Signalised. Similar to Do-

Min with additional TH lane

on each Ruahine St

approach and LT lane on

Ruahine St N. LT Slip lane

on Ruahine S is removed.

Wellington Road / Ruahine

Street

Priority intersection.

Wellington Rd S

approaches give way to

Ruahine St and Wellington

St E

Signalised. Wellington St E

has 2 TH lanes and a LT slip

lane, Ruahine St has 2 TH

lanes and a RT lane.

Wellington S has a RT lane

and a signalised LT lane

Signalised. Similar to Do-

Min with additional TH lane

on Wellington St E and

additional RT lane on

Wellington St S.

Wellington Road / Walmer

Street Priority intersection

Signalised. No widening is

proposed. Single lane

approach for Walmer Street

Closed. Walmer Street

accessed via a service lane

from Moxham Avenue

Kilbirnie Crescent /

Wellington Road

Signalised. Wellington

Road E approaches with

RT lane, 2 TH lanes and

LT slip lane. Wellington

Road W with RT lane, TH

lane and shared TH/LT

lane. Hamilton Road with

RT lane, shared TH/LT

lane. Kilbirnie Crescent

has shared RT/TH and LT

slip lane

As existing except LT lane on

Kilbirnie Cr approach is

signalised and an additional

RT lane is added to the

Hamilton Road approach

Additional TH lane on

Wellington Rd E and W

approaches. Left slip lane

on Wellington east

approach becomes a shared

TH/LT lane. Kilbirnie Cr and

Hamilton Rd approaches

change to LT slip, Bus lane

and shared TH/RT lane


May 2011

Evans Bay Parade /

Cobham Drive

Signalised. Wellington

Road W and Cobham Dr

approaches with RT lane,

2 TH lanes and LT slip

lane. Evans Bay Parade N

and S have RT lane, TH

lane and LT slip lane.

As existing except LT slip on

Evans Bay Parade is signalised

As Do-Min with additional

TH lane on Cobham Dr and

Wellington Rd W. LT slip

lane on Wellington W

approach is changed to LT

lane.

5.3 Accommodating alternative views and approaches

The traffic modelling of the study corridor has highlighted the large demand for travel through the study

corridor using high growth scenario assumptions. The demand is reflected with the existing corridor at

capacity at present and it will be under pressure when subjected to future forecasts. The current operation

results in vehicles finding alternative routes which, in the majority of cases, involve the use of local roads.

Upgrades along the State Highway increase the capacity of the corridor. This does not always lead to

improvements in performance at the intersections or of the corridor itself. Rather, the additional capacity

is consumed by an increased proportion of vehicles using the corridor. However, this does produce

significant decreases in traffic using local roads enhancing the network performance as a whole.

The large demand associated with this corridor, and the questions regarding the ability of the road to

meet an acceptable level of service, has meant the focus of the study must be shifted to what can be

provided in an appropriate context within the corridor.

The corridor is placed in an urban environment and is relatively confined from a land perspective,

particularly on Wellington Road where the road is lined with property on either side. Along Ruahine Street

the corridor is lined by property on the eastern side, and town belt land on the west. The corridor has

been designed to a speed of 60km/h. Achieving a higher design speed was considered desirable from an

operational perspective, but had to be weighed up against the effect on property and access, land take

and the requirement to tie into the Basin Reserve scheme.

The views of Wellington City Council have been considered in developing the preferred route alignment

though the corridor. Town belt land on the western side of Ruahine Street is required to accommodate the

widening of the corridor through this section. Property on the northwest corner of the Wellington

Road/Ruahine Street intersection will be required for the realignment of the State Highway between

Ruahine Street and Wellington Road. The strip of property lining the southern side of Wellington Road

between Ruahine Street and Kilbirnie Crescent is required for road widening purposes, as well as a small

portion of Kilbirnie Park to the east of the Kilbirnie/Wellington Road intersection.

Several workshops were convened during the study, and the views of urban designers, heritage experts

and architects were solicited to provide input and inform the engineers of their views and principles whilst


May 2011

the alignment of the State Highway was being developed. This became of increasing importance when the

preferred option was taking shape.

5.3.1 Urban design

The main urban design principles which have been identified and are being addressed throughout the

design of the project include:

� Accentuate existing shifts in environment along the journey through design

� Observe and build on the historical networks, urban structure, and linkages to different centres

� Situate the road between the structure of Hataitai and the Town Belt and retain the integrity of each in

form, fabric, and networks

� Optimise the quality of the corridor, its edges and interface

� Manage perception and impact of the road and tunnels by reducing the area of impact, by keeping

the tunnels together or physically separating road structures

� Build on social connectivity by respecting significant urban facilities and connections

� Improve multi-modal connectivity by understanding and building on existing networks

� Maintain sense of cohesive definable communities that exist in Hataitai, Kilbirnie and Mt Victoria.

Further detail on how these issues are being addressed is discussed in the Urban Design Technical report.

5.3.2 Heritage

All buildings located in the Mt Victoria suburb are subject to the pre-1930s demolition rule that requires a

consent to demolish a building which is older than 1930. The preferred option involves the removal of a

number of properties to the north of Paterson Street. Some of the buildings in the study area in Mt Victoria

fall within this category and have the potential to require consent for alteration or removal. The number of

these buildings which are pre-1930s needs to be considered further in the next phase of the project.

The following heritage buildings have been identified as within the study area of the Mt Victoria to

Cobham Drive study area:

• Ettrick Cottage at 19 Paterson Street. This building has been moved once before from Austin

Street following work on the ICB. It was built in the early 1870s, and was bought by Samuel

Atkins, a sergeant in the Seaforth Highlanders. The home remained in the Atkins family for 81

years.

• 7 Paterson Street. Built in 1869, the property was the original home of William Waring Taylor, a

member of the House of Representatives.

The northern tunnel option requires the removal of both of the properties identified above.

On the eastern side of the tunnel, the 1930s demolition rule does not apply. No heritage properties are

listed along the Ruahine Street and Wellington Road corridor.


May 2011

5.3.3 Community severance

Under the existing situation, the high traffic volumes on Ruahine Street and Wellington Road create a

sense of community severance between Hataitai and the Hataitai Park. The corridor is particularly hard to

cross. A grade separated pedestrian crossing currently connects the Hataitai Village to the Town Belt. The

preferred option is unable to retain the existing elevated crossing, but the intention is to replace the

former with some form of grade separated crossing facility at this point accommodating cyclists and

pedestrians.

The signals at the Wellington Road/Ruahine Street and Ruahine Street/Goa Street intersections will allow

the addition of signalised pedestrian crossing points to be provided which will greatly decrease the

severance issue currently experienced along the corridor.

The issue of vehicle access to Hataitai village is important when considering community severance. The

preferred option involves removing all vehicular access to Taurima Street except the left turn in. The

access arrangement has been modified to increase safety and operation of the intersection. Local business

and residents in Hataitai may experience a degree of severance as a result, and options to retain some of

the removed movements are being explored. However, the closure could enable a parking area to be

provided for access to neighbouring shops or the Town Belt and Hataitai Park.

5.3.4 Construction disruption

On the western side of the Mt Victoria Tunnel the northern and southern tunnel options both have a

significant effect on surrounding property.

As described in Section 3.1.2, the southern tunnel option involves land take from the southern side of

Paterson Street which is occupied by Wellington College and Wellington East Girls College. The

construction period of building a duplicate tunnel will have a significant disruption effect on the school.

The northern duplicate tunnel option involves the removal of the majority of the properties lining Paterson

Street on the northern side; however NZTA currently owns the majority of these properties.

On the eastern side of the tunnel, the southern tunnel alignment will require land from the Town Belt and

will impact on the road used to exit the Velodrome. In order to construct the portal, a section of cut and

cover will be required which would have a significant impact on Hataitai Park, removing the access road

and the parking area directly to the east of the netball courts. The netball championship court will also be

unavailable for the duration of the construction period.

The northern tunnel alignment means that the Kindergarten on the corner of Taurima Street would need to

be removed. The option would require Town Belt land to be used for the construction of the portal.


May 2011

5.3.5 Environmental issues

The Town Belt provides a scenic back-drop to the inner city, and is a valuable asset offering recreational

opportunities. Any attempts to encroach on Town Belt land are likely to be opposed.

Vegetation is a significant feature in the visual and ecological environment. Vegetation in the Town Belt is

protected by legislation which needs to be considered if Ruahine Street is to be widened. The established

Pohutukawa and Macrocarpa trees immediately adjacent to the road on Ruahine Street provide a

significant landscape and ecological resource. The trees on the northern side of Ruahine Street

immediately adjacent to the Wellington Road/Ruahine Street intersection will be affected by the

realignment of the corner.

Presently the preferred option involves a 60km/h design curve on the Wellington Road/Ruahine Street

intersection. By reducing the design speed of this curve, the affected area of town belt land can be

reduced together with the effect on valuable ecological environments. Options are currently being

explored involving minor changes to the alignment to reduce the effect on town belt land, reduce cuttings

and still provide adequate operational characteristics.

5.3.6 Noise assessment

The noise assessment of the northern and southern tunnel alignment options indicate some benefits to

the southern tunnel as it has a greater degree of separation from the residential settlement on either end

of the tunnel.

5.3.7 Air quality

The air quality assessment indicates no significant difference between northern and southern tunnel

options. The monitoring data indicates that the likely worst case air quality (based on maximum

observations) will comply with the relevant national guidelines and standards for ambient air.

5.4 Reflecting principles in the preferred option

5.4.1 Retaining access

Currently a number of properties along the eastern side of Ruahine Street gain access directly onto the

State Highway. Red stars on the figure below indicate properties which currently have vehicle access onto

Ruahine Street.


May 2011

Figure 5-1: Property access on Ruahine Street

With widening on the western side of Ruahine Street, the Badminton Hall and the property on the corner of

Wellington/Ruahine Street are likely to be required to be removed, so access to these properties will not

be an issue. Of more concern is the number of properties clustered around the Goa Street intersection

which currently have direct access onto the State Highway. Many of these properties have garages and

perform reverse manoeuvres onto Ruahine Street to get out.

Widening on the eastern side of Ruahine Street would require the western-most row of houses for

widening. This includes all property which currently has access to the State Highway. No access would

need to be provided on the eastern side of Ruahine Street. The Badminton Hall would be retained in its

existing position and access would need to be provided.

Property access on Wellington Road is generally provided for the entire length on either side of the road

from the Wellington Road/Ruahine Street intersection to the Kilbirnie/Wellington Road intersection.

Properties on the northern side of Wellington Road between Kilbirnie Crescent and Evans Bay Parade


May 2011

currently have direct access to the State Highway. Figure 5-2 indicates properties which currently gain

access onto Wellington Road with a red star symbol.

Figure 5-2: Property access on Wellington Road

With widening on the south of Wellington Road, the row of property on the southern side of Wellington

Road is intended to be used for road widening purposes, so no access will be needed to these properties.

Access into and out of Moxham Avenue and Walmer Street is intended to be removed from the State

Highway. Access to Walmer Street will be maintained through the construction of a service lane connecting

to the southern end of Moxham Avenue.

The option including widening to the north of Wellington Road would remove the properties which

currently access the State Highway directly on the northern side. The row of property to the south between

Wellington Road and Kilbirnie Crescent would need access to be provided. Access into and out of Moxham

Avenue and Walmer Street is intended to be removed from the State Highway. Access to Walmer Street will

be maintained through the construction of a service lane connecting to the southern end of Moxham

Avenue.

Whilst vehicle access from property on Ruahine Street and Wellington Road onto the State Highway is

appropriate in the current situation due to the additional width from the on-street parking and single lanes

of traffic in each direction, the proposed option removes any shoulder and adds additional lanes and will


May 2011

attract more traffic. It is not considered appropriate to allow these properties direct access to the State

Highway.

Options to widen the State Highway include a service lane providing access to property on the eastern side

of Ruahine Street and the northern side of Wellington Road. This service lane will run parallel to the

highway and provide access to property as well as providing for pedestrians and cyclists. An indicative

sketch of the service lane is shown in Figure 5-3. This facility will allow for the shared use of pedestrians,

cyclists and motor vehicle users of those properties affected by the road scheme. Parking/passing bays

will be provided at regular intervals to allow vehicles an opportunity to pass pedestrians and cyclists. This

will involve removing the planting strip for a short section to provide additional width to the access-way.

Figure 5-3: Indicative shared pedestrian/cycle/access way

5.4.2 Retaining parking space

In the existing situation, on-street parking is available for a 190m section on the eastern side of Ruahine

Street. Whilst properties adjacent to this parking generally have off-street parking or access to Moxham

Avenue instead, this parking is also heavily utilised by visitors to the Hataitai Park sports facilities.

All of the short-listed options close all movements except the left into Taurima Street at the Taurima

Street/Ruahine Street intersection and as a result could lead to an area of unused land being created.

Options are being considered which involve providing additional parking for the Hataitai Park in this

location.

Currently, on-street parking is permitted on the northern side of Wellington Road. This parking is believed

to be utilised mostly by residents on Wellington Road. The majority (but not all) of property along the


May 2011

northern side of Wellington Road have off-street parking. Arrangements will be considered to provide

adequate parking for these properties.

Ruahine Street and Wellington Road have long been identified as a road corridor. Removal of the on-street

parking to improve traffic efficiency and safety should come as no surprise, although residents may be

inconvenienced with increases in walking distance to access their vehicles.

5.4.3 Enhancing pedestrian and cycling facilities and connection

Following the scoping stage of the Mt Victoria to Cobham Drive study, the preferred option for a duplicate

Mt Victoria Tunnel has been identified as the northern tunnel. The need for a pedestrian/cycle space to

double up as a fire egress to both the Mt Victoria and duplicate tunnel has meant that the preferred option

for pedestrians and cyclists is to place them inside the duplicate tunnel with a dual function of providing

egress to both tunnels.

The provision for pedestrians and cyclists can be accommodated in a duplicate tunnel but attracts

additional cost. The pedestrian and cyclist pathway would be positioned on the northern side to best align

with the desire lines of pedestrians and cyclists from the eastern suburbs. With a northern duplicate

tunnel, treatment on either end will remain similar to the existing situation with pedestrians and cyclist

entering and exiting on the northern side of the State Highway. This arrangement allows pedestrians and

cyclists on the eastern side of Mt Victoria to be directed along Taurima Street to Moxham Avenue, or

remain alongside the highway on a new pedestrian/cycle path.

From the eastern side of Mt Victoria and once they enter the duplicate tunnel, pedestrians and cyclists will

travel down the northern side of Paterson Street and feed into the CBD on the north-eastern side of the

Basin Reserve. For CBD destinations this will mean travelling along Paterson Street and using Brougham

Street. Opus, as part of the Basin Reserve Study, will be determining how to link Paterson Street with cycle

facilities to the north of Buckle Street and also to Adelaide Road and Newtown.

On the eastern side of the tunnel, the main catchment for pedestrian and cycle trips is to the Hataitai

suburb which is to the north of the tunnel portal. It is considered important to provide convenient access

to Hataitai village. The preferred option provides access to the pedestrian/cycle facilities from the north

via Taurima Street.

The preferred option includes a 6m-wide service lane on the eastern side of Ruahine Street and the

northern side of Wellington Road. This lane provides a continuous pedestrian and cycling facility from the

western tie-in to Paterson Street through the Mt Victoria Tunnel and alongside the highway to the Cobham

Drive intersection tying in to the existing shared pedestrian/cycle path on Cobham Drive.

The service lane alongside Ruahine Street and Wellington Road is intended to provide space for property

access in the form of a one directional service lane as well as pedestrians and cyclists. There are several

properties likely to make use of this service lane which presently have access to the highway. Within the

6m width, a 1.5m strip of vegetation will separate the service lane from the main carriageway, with a 4m


May 2011

shared lane for limited vehicle access, pedestrians and cyclists. A 0.5m offset would be provided between

the service lane and properties. A signalised crossing point will be provided at the Goa Street intersection

which will allow pedestrians and cyclists and any vehicles using the service lane a safe crossing point

should they wish to access Hataitai Park.

Alternative routes are available via Hamilton Road and Moxham Avenue for pedestrians and cyclists. This

route may be more appropriate for pedestrians due to interaction with local communities rather than

remaining remote along the service lane. The traffic on Moxham Avenue may offer an improved sense of

security during quieter times for pedestrians.

5.4.4 Sensitive landscaping

Significant cuts will be required on the western corner of Wellington Road and Ruahine Street. Further cuts

will be required along the western side of Ruahine Street as the road widening extends into the Town Belt

land. High level assumptions on the types of cuts that could be used are discussed in more detail in the

Engineering and Construction Technical Report10.

From a traffic and transport perspective, the cuts should be made in such a manner as to provide

adequate sight distance at the Wellington Road and Ruahine Street intersection.

At the Ruahine/Wellington Street corner, the critical location for sight distance is the north-eastern corner

of the intersection which is currently occupied by private properties. The cuts are located in the Town Belt

with established Pohutukawa and Macrocarpa trees immediately adjacent to the road on Ruahine Street

providing a significant landscape and ecological feature. Cuts will be designed to have a minimal impact

on this sensitive environment whilst still providing adequate road safety.

The most significant cuts will be immediately west of the Ruahine Street/Wellington Road intersection

south of the Badminton Hall. The existing bluffs will need to be cut back and the exposed areas will

require sensitive landscaping.

5.4.5 Portal treatment

Portal locations for the northern duplicate tunnel are outlined in Section 3.1.1. The final 50m from the

tunnel portal will take the form of a cut and cover section. This will involve significant cuts and

considerable earthworks. The cut form and landscaping will be designed to take account of the project’s

Urban Design principles and surrounding environment. The tunnel portal itself needs to fit with the

existing portal and urban fabric of the area.

10 Wellington Tunnels Alliance, 2011. Mt Victoria to Cobham Drive Scoping Study. Technical Report: Engineering and

Construction


May 2011

6 Traffic analysis

Results from a recently validated 2009 SATURN model were received from Opus in February 2011. This

model included inputs from the high growth scenario WTSM model run for the 2016 and 2026 design

years. Demands from the SATURN model were used to input into SIDRA to assess individual intersection

performance.

A number of performance measures have been extracted from the WTM SATURN model including travel

time of the network, vehicle operating costs of the network and volumes of traffic on key State Highway

and local road links.

6.1 2009 base

In the 2009 base case, intersections have been modelled as per the existing layout on the corridor. Two

intersections are currently signalised including Kilbirnie Crescent/Wellington Road and Cobham

Drive/Evans Bay Parade. All other intersections in the corridor are currently priority controlled

intersections. The State Highway approaches experience minimal delay as a result of the intersections.

Side roads suffer from significant delay due to the high level of traffic on the SH route during peak

periods.

6.1.1 Taurima Street intersection

The Taurima Street priority controlled intersection operates well on the SH approaches, but the Taurima

Street eastern approach operates with a significant delay. The degree of saturation (DOS) of the Taurima

Street eastern approach far exceeds capacity and results in large queuing and delay. The models indicate

excessive delay on Taurima Street east approach. It is unlikely vehicles will experience an average delay of

about 30 minutes, however. It is likely the intersection operates better than the model predicts with

vehicles picking smaller gaps. Vehicles will re-route on alternative routes once the associated delay with a

movement becomes too large.


May 2011

Table 6-1: Taurima Street intersection performance

Taurima StreetTraffic

demand Approach DOS

Average

Delay (s)LOS

95th

percentile

back of

queue (m)

Left in Left out2009 AM peak Overall 2.86 163 n/a 860

Ruahine St 0.74 6 A 0

Taurima St E 2.87 1637 F 860

Taurima St N 0.71 7 A 0

Left in Left out 2009 PM Peak Overall 2.07 67 n/a 481


Taurima St E 2.06 1000 F 481


6.1.2 Moxham Avenue intersection

The Moxham Avenue intersection is currently a priority controlled intersection with priority given to the

north-south traffic on Moxham Avenue. The intersection experiences low traffic volumes in the current

situation and as such operates with a good LOS and low average delay to vehicles.

Table 6-2: Moxham Avenue intersection performance

Moxham AvenueTraffic

demand Approach DOS

Average

Delay (s)LOS

95th

percentile

back of

queue (m)

Do minimum2009 AM peak Overall 0.12 3 n/a 6

Moxham Rd S 0.10 2 A 6

Goa St E 0.05 12 B 2

Moxham Rd N 0.12 1 A 6

Goa St 0.04 12 B 1

Do minimum2009 PM Peak Overall 0.14 2 n/a 10

Moxham Rd S 0.14 0 A 10

Goa St E 0.01 14 B 0

Moxham Rd N 0.12 0 A 7

Goa St 0.14 13 B 5

6.1.3 Goa Street intersection

The Goa Street intersection operates as a priority intersection with the north-south traffic on Ruahine

Street having priority. The Ruahine Street approaches operate with LOS (A) during both peak periods. The


May 2011

Goa Street and Hataitai Park approaches cannot find sufficient gaps in traffic and as a result experience a

high average delay and LOS (F).

The models indicate excessive delay on Goa Street east approach, and whilst this does indicate an

operational problem with the priority intersection, it is unlikely vehicles will experience an average delay

to the level predicted. It is likely the intersection operates better than the model predicts with vehicles

picking smaller gaps and driver courtesy allowing vehicles to turn onto the State Highway. Vehicles will re-

route on alternative routes once the associated delay with a movement becomes too large.

Table 6-3: Goa Street intersection performance

Goa StreetTraffic

demand Approach DOS

Average

Delay (s)LOS

95th

percentile

back of

queue (m)

Existing Scenario

(Base)2009 AM peak Overall 1.00 11 n/a 98

Ruahine St S 0.72 0 A 95

Goa St 1.00 711 F 74

Ruahine St N 0.71 1 A 98

Hataitai Park 0.69 160 F 14

Existing Scenario

(Base)2009 PM Peak Overall 1.00 9 n/a 86

Ruahine St S 0.71 1 A 86

Goa St 1.00 786 F 58

Ruahine St N 0.65 1 A 70


Existing Scenario

(Base)

2009 Saturday

PeakOverall 1.91 77 n/a 317

Ruahine St S 0.73 4 C 144

Goa St 1.00 732 F 93

Ruahine St N 0.58 4 C 51


Under the existing situation, the Goa Street/Ruahine Street intersection experiences significant demands

during the Saturday peak periods. The Hataitai park sports area generates a significant amount of traffic

during the weekend peaks which use the intersection as the sole point of access. A Saturday peak model

has been built based on peak hour survey results from 2007.

During the Saturday peak period the Goa Street intersection operates above capacity. The Goa Street and

Hataitai Park approaches experience large delay and queuing as there are insufficient gaps for vehicles to

enter the highway traffic.


May 2011

6.1.4 Wellington Road intersection

The State Highway approaches at the intersection of Wellington Road/Ruahine Street is operating at a LOS

(A). The Wellington Road south approach cannot find sufficient gaps in the State Highway traffic stream

and as a result experiences a high average delay and LOS (F).

The models indicate excessive delay on Wellington Road south approach. It is unlikely vehicles will

experience an average delay of about 10 minutes, however. It is likely the intersection operates better

than the model predicts with vehicles picking smaller gaps and courteous behaviour from through traffic.

Vehicles will re-route on alternative routes once the associated delay with a movement becomes too large.

Table 6-4: Wellington Road intersection performance

Wellington

Road/Ruahine Street

Traffic

demand SH Approach DOS

Average

Delay (s)LOS

95th

percentile

back of

queue (m)

Existing Scenario

(Base)2009 AM peak Overall 1.05 44 n/a 121

Wellington Rd E 0.74 7 A 18


Wellington Rd S 1.05 937 F 121

Existing Scenario

(Base)2009 PM Peak Overall 1.15 35 n/a 125

Wellington Rd E 0.72 7 A 14


Wellington Rd S 1.15 593 F 125

6.1.5 Kilbirnie Crescent intersection

The Kilbirnie Crescent intersection is currently operating at capacity on the State Highway approaches

during the morning and afternoon peak periods. The Kilbirnie Crescent approach is operating above

capacity in the existing situation. Large queues occur on the Wellington Road western approach reaching

500-600m depending on the peak period.


May 2011

Table 6-5: Kilbirnie Crescent intersection performance


Wellington Road

Traffic


Average

Delay (s)LOS

95th

percentile

back of

queue (m)

Existing Scenario

(Base)2009 AM peak Overall 1.09 62 E 591

Kilbirnie Cr 1.09 90 F 315

Wellington Rd E 1.00 29 C 257

Hamilton Rd 0.55 51 D 86

Wellington Rd W 1.00 81 F 591

Existing Scenario

(Base)2009 PM Peak Overall 1.05 42 D 457

Kilbirnie Cr 1.02 47 D 185



Wellington Rd W 1.00 51 D 457

The Evans Bay Parade intersection is currently operating at or approaching capacity on the State Highway

approaches during the morning and afternoon peak periods. The Wellington Road approach is at capacity

whilst Cobham Drive operates at LOS (C/D). Large delay is associated with the State Highway approaches.

Large queues form on the Wellington Road approach during both peak periods.

Table 6-6: Evans Bay Parade intersection performance

Cobham Drive/Evans

Bay Parade

Traffic


Average

Delay (s)LOS

95th

percentile

back of

queue (m)

Existing Scenario

(Base)2009 AM peak Overall 1.02 52 D 385

Evans Bay S 0.93 44 D 61

Cobham Dr 1.00 31 C 219

Evans Bay N 1.00 26 C 93

Wellington Rd 1.02 95 F 385

Existing Scenario

(Base)2009 PM Peak Overall 1.06 74 E 532

Evans Bay S 1.06 84 F 188

Cobham Dr 1.03 41 D 150




May 2011

6.1.6 Travel time

Travel time through the study area is provided in Table 6.7. Increases of between 4% and 22% can be

observed in the existing situation and the ‘Do Nothing’ scenario for 2026. A larger time saving is achieved

in the peak direction of travel during each peak.

Table 6-7: Travel time through the SH Corridor

Scenario

Period

Terrace tunnel to Cobham Drive /

Evans Bay Parade (West-bound)

Cobham Drive / Evans Bay Parade

to Terrace Tunnel (East-bound)

Time (s) Average Speed

(km/h) Time (s)

Average Speed

(km/h)

2009 Base

AM

Peak 729 29 668 31

PM

Peak 722 29 742 28

2026 ‘Do

Nothing’

AM

Peak 888 24 698 30

PM

Peak 867 24 808 26

Some of the changes to travel time may appear marginal. It should be appreciated that the State Highway

is at capacity during the peak hours in the existing situation and by 2026; additional traffic wanting to use

the State Highway cannot be accommodated and is obliged to use alternative routes.


May 2011

6.2 2026 ‘Do Minimum’ and Tunnels Alliance option

SIDRA modelling has been updated at each of the existing and proposed signalised intersections within

the study area. The ‘Do Minimum’ scenario has been largely based on the Ruahine Street PFR produced by

OPUS in June 2010. As described previously, the ‘Do Minimum’ option includes the Mt Victoria Tunnel as is

with four lanes along both Ruahine Street and Wellington Road.

The Tunnels Alliance option has been developed through past modelling, and optimisation of the corridor

from a traffic operation, urban design and cost perspective. The option involves the at-grade upgrade of

several intersections. Summaries of the intersection performance for the ‘Do Minimum’ and Tunnels

Alliance options are given in the tables below.

6.2.1 Traffic volumes

Traffic volumes at key locations on both the State Highway and local roads have been pulled out of the

model to provide insight into the level of re-routing occurring under different scenarios. Peak hour flows

from the morning, inter-peak and afternoon have been combined and converted to a seven-day AADT.

Table 6-8 sets out the conversion rates which have been used:

Table 6-8: Conversion Rates for AADT

Time Period Representative hrs/day

in a week

Weekday AM Peak 2

Weekday Inter-Peak 7

Weekday PM Peak 2

Weekday Off-peak/Night

(0.30*IP ) 13

Weekend/Holiday Day Time

(1.13*IP ) 8

Weekend/Holiday Night

(0.36*IP ) 16

Table 6-9 provides AADT volumes on key sections of State Highway and on local roads which can be used

as alternatives to the State Highway corridor. Three variations of preferred option have been included in

this analysis, all of which are predominantly the same with slight changes to the permitted side road

movements. These include:

• Option with Taurima Street/Ruahine Street restricted to left in

• Option with Taurima Street/Ruahine Street connection completely removed

• Option with Taurima Street Ruahine Street restricted to left in left out and Wellington

Road/Ruahine Street restricted to left in only.


May 2011

These options were compared with the ‘Do Minimum’ and existing networks.

Table 6-9: Traffic volumes on key links from WTM

Traffic Volumes on Key links 2009 Base2026 Do

Nothing

2026 Do

Min

2026

Option

Taurima

Street LILO

2026

Option

Taurima

Street

closed

2026

Option

Taurima

Street

LILO and

Wellingt

on Road

LILO

Cobham Drive (East of the Evans Bay

Parade intersection)40400 52000 53100 54100 54100 53900

Wellington Road (Between Evans Bay

Parade and Kilbirnie intersection)39200 48600 50300 53500 54100 53000

Ruahine Street (Between Wellington

Road and Goa Street)37500 44400 43800 61800 62400 62800

Mt. Victoria Tunnel/s41600 49500 47200 71500 71100 70900

Moxham Avenue (North of Goa Street)5300 7700 10100 11500 11700 9100

Moxham Avenue (North of Taurima

Street)8800 12300 17800 16500 13500

Palliser Road (west of Grafton Road)4700 9900 10900 5500 5400

Rongotai Road (east of Onepu Road)9100 10300 11300 8700 11200

Riddiford Street (south of Mein Road)33800 43100 43200 38900 38800

Adelaide Road (South of the Basin

Reserve)34000 50100 49600 53000 54000

Constable Street (east of Coromandel

Street)30500 31400 32200 33300 31800

Oriental Parade (North of Evans Bay

Parade intersection)13700 21300 23300 13000 13100 12000

Sta

te h

igh

wa

yLo

cal ro

ad

s

The option provides significant increases to the throughput of traffic on the State Highway corridor over

the ‘Do Minimum’, ‘Do Nothing’ and existing scenarios. This can be observed by volumes through the Mt

Victoria Tunnel which increase by about 70% over the existing volumes and 50% over the ‘Do Minimum’

scenario.

Volumes on Cobham Drive east of the Evans Bay Parade intersection remain largely consistent between

options for 2026. The ‘Do Nothing’ scenario results in about 2000 less vehicles as a result of the

congestion and lack of capacity on the State Highway network. Significant changes can be seen at the

Evans Bay Parade/Cobham Drive intersection. A significant proportion of traffic in the ‘Do Minimum’ and

‘Do Nothing’ scenarios divert along Evans Bay Parade (Oriental Parade). The Option is able to

accommodate additional through traffic on the State Highway and, as a result, similar traffic levels around

Oriental Parade as in the existing situation. The option halves the traffic on Oriental Parade and effectively

maintains it at 2009 levels.


May 2011

Significant changes to volumes on Palliser Road can be seen between the ‘Do Minimum’/’Do Nothing’ and

the Option. Under the ‘Do Minimum’/’Do Nothing’ scenario insufficient capacity on the State Highway

means a large proportion of vehicles need to find alternative routes. Palliser Road is a steep narrow road

over Mount Victoria through Hataitai. The volume of traffic using this road doubles from existing levels in

the ‘Do Minimum’ and ‘Do Nothing’ scenario. Under the option volumes are kept roughly to existing

levels.

Moxham Avenue experiences increases in traffic in the ‘Do Nothing’, ‘Do Minimum’ and Option scenarios

when compared with the present situation. This comes as a result of banning some movements at Taurima

Street, meaning all vehicles heading west from Hataitai must travel on this link to gain access to the State

Highway. In the ‘Do Nothing’ case, the right turn from Taurima Street is allowed, but high levels of traffic

on Ruahine Street mean that the turn does not operate well.

The option which closes of Taurima Street (2026 Option Taurima Street closed) appears to have little

effects to volumes on the State Highway. Volumes on Moxham Avenue remain consistent with levels seen

when the left in movement is allowed. Traffic which would ordinarily use the left in is forced onto the State

Highway at Goa Street/Ruahine Street or Hamilton Road/Kilbirnie Crescent.

The option which restricts movement at Wellington Road to left in left out attracts similar volumes on the

State Highway. Changes can be seen on Moxham Avenue where the restriction of movements at Wellington

Road seems to reduce traffic slightly over the options with full movements. An increase in traffic volumes

on Rongotai Road can be observed as a result of the restriction at Wellington Road.

6.2.2 Travel time savings

The travel time data indicate significant reduction in delay to the State Highway in both directions. The

preferred option results in approximately four minutes of travel time savings in the west-bound direction,

with between 2.5 and 3 minutes in the east-bound direction over the ‘Do Minimum’ scenario. It also

results in average speed increases of between 6km/h and 13km/h.


May 2011

Table 6-10: Travel times through study area

Scenario

Period

Terrace tunnel to Cobham Drive

/ Evans Bay Parade (West-

bound)

Cobham Drive / Evans Bay

Parade to Terrace Tunnel (East-

bound)

Travel Time (s) Ave Speed

(km/h) Travel Time (s)

Ave Speed

(km/h)

2009 Base

AM

Peak 729 29 668 31

PM

Peak 722 29 742 28

2026 ‘Do

Nothing’

AM

Peak 888 24 698 30

PM

Peak 867 24 808 26

2026’ Do

Minimum’

AM

Peak 813 26 723 29

PM

Peak 775 27 866 24

2026 Option TA1

AM

Peak 569 36 565 36

PM

Peak 511 40 691 30

6.2.3 Taurima Street/Ruahine Street

Under the ‘Do Minimum’ and Tunnels Alliance option all turning movements except the left turn from

Taurima Street north into Taurima Street east are banned. The intersection operates with a good LOS with

no significant delay or queuing.

An additional intersection option at Taurima Street/Ruahine Street involved closing the connection to

Taurima Street. This option has not been modelled as the intersection would no longer exist. The majority

of traffic which would make use of Taurima Street would need to use the Ruahine Street/Goa Street

intersection instead. The resulting additional traffic has been modelled at the Goa Street intersection.


May 2011

Table 6-11: Taurima Street intersection summary

Taurima Street Traffic demand Approach DOSAverage

Delay (s)LOS

95th

percentile

back of

queue (m)

Do minimum - Left in 2026 TA AM peak Overall 0.55 6 n/a 0



Do minimum - Left in 2026 TA PM peak Overall 0.50 6 n/a 0



Tunnels Alliance Option 2026 TA AM peak Overall 1.00 6 n/a 0

Left in Only Ruahine St 1.00 6 A 0


Tunnels Alliance Option 2026 TA PM peak Overall 0.79 6 n/a 0

Left in Only Ruahine St 0.79 6 A 0


6.2.4 Moxham Avenue/Goa Street

The Moxham/Goa Street intersection is signalised in the ‘Do Minimum’ model with a right turn slot being

added to the Moxham Avenue north approach. The Moxham Road south approach experiences a 200m

queue in the morning peak period due to left turning traffic. The Goa Street approaches operate at a LOS C

during the morning peak.

The signalised intersection operates with a similar average delay to the ‘Do Minimum’ scenario. The

largest queues are experienced on the Moxham Road north approach. Queues on Goa Street remain within

the available queuing space.


May 2011

Table 6-12: Moxham Avenue intersection summary

Moxham Avenue Traffic demand Approach DOSAverage

Delay (s)LOS

95th

percentile

back of

queue (m)

Do minimum 2026 TA AM peak Overall 0.70 19 B 200

Moxham Rd S 0.70 16 B 200

Goa St E 0.03 46 D 3

Moxham Rd N 0.64 22 C 77

Goa St 0.16 41 D 21

Do minimum 2026 TA PM peak Overall 0.42 19 B 79


Goa St E 0.02 33 C 2


Goa St 0.16 27 C 26

Tunnels Alliance Option 2026 TA AM peak Overall 0.65 22 C 122


Goa St E 0.02 30 C 2


Goa St 0.32 22 C 33

Tunnels Alliance Option 2026 TA PM peak Overall 0.67 21 C 114


Goa St E 0.02 28 C 2


Goa St 0.44 22 C 47

6.2.5 Goa Street/Ruahine Street

The Goa Street/Ruahine Street intersection is proposed to be signalised in the ‘Do Minimum’ scenario. The

intersection operates at a LOS (E) during the morning peak and LOS (D) during the afternoon peak. The

Ruahine Street north approach is essentially operating at capacity and as a result experiences a queue in

the vicinity of 600m.

In the Tunnels Alliance option, the intersection is upgraded to accommodate three through lanes in each

direction. In addition, a left turn is added to the Ruahine Street north approach. The improvements to this

intersection and the limited movements available at Taurima Street mean a significant increase in traffic is

experienced at the Goa Street intersection. During the morning peak, the intersection operates at a LOS

(F), mainly due to the significant increase in volume of through traffic on the Ruahine Street south

approach. The delay and queue length on this approach represent an increase over the ‘Do Minimum’

scenario and represent a congested state for the corridor. During the afternoon peak, the intersection

operates at LOS (C) with less delay than the ‘Do Minimum’ scenario.

The significant increase in through traffic at the Goa Street intersection represents a large proportion of

vehicles which previously made use of local roads being attracted to the State Highway route. While the

improvements to capacity at the intersection do not appear to offer improved localised gains, the network

as a whole will operate more efficiently with the roading hierarchy reinforced.


May 2011

Although the WTM model does not include the Saturday peak period in its future forecasting, an

approximation as to the expected volumes of traffic has been made. Saturday peak period traffic from

2007 was used as a base, with the traffic factored up according to the changes between 2009 Base

demands and 2026 demands. The 2026 demands are a best guess estimate to likely traffic volumes at the

intersection.

During the Saturday peak period, the Goa Street/Ruahine Road experiences a substantial increase in

turning traffic. This, in turn, means additional green time is needed for Hataitai Park and Goa Street

approaches. Under the preferred option, all approaches except the Goa Street approach are at capacity

and sizable queues and delays are experienced.

Table 6-13: Goa Street intersection summary

Goa Street Traffic demand Approach DOSAverage

Delay (s)LOS

95th

percentile

back of

queue (m)

Do Minimum 2026 TA AM peak Overall 0.99 56 E 601

Ruahine St S 0.91 40 D 411

Goa St 0.25 49 D 84

Ruahine St N 0.99 73 E 601

Hataitai Park 0.24 49 D 18

Do Minimum 2026 TA PM peak Overall 0.99 55 D 583


Goa St 0.11 44 D 39



Do Minimum 2026 TA Saturday peak Overall 1.00 54 D 452

Ruahine St S 0.97 64 E 451

Goa St 0.28 62 E 29

Ruahine St N 1.00 40 D 298

Hataitai Park 0.87 60 E 78

Tunnels Alliance Option 2026 TA AM peak Overall 1.11 102 F 1041

Ruahine St S 1.11 161 F 1041

Goa St 0.49 51 D 79





Goa St 0.44 51 D 73

Ruahine St N 0.89 35 D 406


Tunnels Alliance Option 2026 TA SAT peak Overall 1.19 148 F 129

Ruahine St S 1.19 221 F 901

Goa St 0.11 40 D 16




May 2011

The Goa Street/Ruahine Street intersection provides an important connection for Hataitai, Hataitai Park

and Kilbirnie. Intersection options at Taurima Street/Ruahine Street and at Wellington Road/Ruahine Street

propose to limit turning movements. This forces some traffic to use Goa Street to connect with the State

Highway. The effects these options have on the Goa Street/Ruahine Street intersection have been

modelled.

With no connection between Taurima Street and the State Highway, the volume of traffic turning left from

Ruahine Street into Goa Street effectively doubles. The closure of Taurima Street increases the through

traffic on the State Highway in the northern direction which leads to slight deterioration in the overall

delay and queuing at the intersection.

The option involving a left in left out arrangement at Wellington Road/Ruahine Street diverts more traffic

up Moxham Avenue and to the Goa Street intersection. The operation of the Goa Street intersection is

similar in the morning peak but decreases in delay and queuing are evident during the afternoon peak.

The table below provides a summary of the intersection performance for the alternative options.

Table 6-14: Alternative Options: Goa Street intersection summary

Goa Street Traffic demand Approach DOSAverage

Delay (s)LOS

95th

percentile

back of

queue (m)

Tunnel Alliance Option 2026 TA AM peak Overall 1.02 60 E 920

No connection at Taurima Ruahine St S 1.02 88 F 920

Goa St 0.58 77 E 85



Tunnel Alliance Option 2026 TA PM peak Overall 1.00 28 C 417

No connection at Taurima Ruahine St S 0.82 25 C 389

Goa St 0.21 66 E 58



Tunnel Alliance Option 2026 TA AM peak Overall 1.12 107 F 1080

Wellington Road LILO Ruahine St S 1.12 170 F 1080

Goa St 0.77 57 E 131



Tunnel Alliance Option 2026 TA PM peak Overall 1.00 57 E 704

Wellington Road LILO Ruahine St S 0.85 28 C 350

Goa St 0.63 53 D 102

Ruahine St N 1.00 83 F 704


6.2.6 Wellington Road/Ruahine Street

Under the ‘Do Minimum’ scenario, the Wellington Road/Ruahine Street intersection is intended to be

signalised. The intersection operates well with LOS (C) in both the morning and afternoon peak periods.


May 2011

Intersections at the upstream and downstream end (Goa Street and Kilbirnie Crescent intersection)

effectively meter the traffic demands to the Wellington Road intersection.

In the Tunnels Alliance option, an additional through lane has been added to the Wellington Road east

approach. Intersection upgrades at the Kilbirnie Crescent intersection increase the capacity for traffic in a

west-bound direction which means more vehicles arrive at the stop line at the Wellington Road

intersection. An additional right turn lane has been added to the Wellington Road south approach. The

Wellington Road east approach operates at capacity in the morning peak period with a large increase in

volume of through traffic. The intersection operates with a LOS (E) during the morning peak and at LOS (D)

in the afternoon peak periods.

Table 6-15: Wellington Road intersection summary

Wellington Road/Ruahine

StreetTraffic demand SH Approach DOS

Average

Delay (s)LOS

95th

percentile

back of

queue (m)

Do Minimum 2026 TA AM peak Overall 0.85 27 C 236


Ruahine St 0.84 21 C 207

Wellington Rd S 0.78 38 C 120

Do Minimum 2026 TA PM peak Overall 0.81 24 C 233



Wellington Rd S 0.81 40 D 133

Tunnels Alliance Option 2026 TA AM peak Overall 1.02 64 E 720

Wellington Rd E 1.02 92 F 720


Wellington Rd S 1.00 76 E 26

Tunnels Alliance Option 2026 TA PM peak Overall 1.00 44 D 501

Wellington Rd E 0.91 50 D 348

Ruahine St 0.92 36 D 501

Wellington Rd S 1.00 49 D 154

An additional option of restricting the Wellington Road/Ruahine Street intersection to only cater for left

turning traffic has been tested. Both the right turn from the Ruahine Street approach and the Wellington

Road south approach have been banned. The intersection has been modelled as a priority intersection.

This allows the through lanes on the State Highway to be reduced to two lanes in either direction apart

from a diverge lane and merge lane on the State Highway. The left turn from Wellington south has been

treated as a lane gain which merges with the two north-bound through lanes. Intersection modelling

indicates the intersection operates well with minimal delay and no associated queuing.

The network-wide effects of changes to traffic volumes on both the State Highway and local roads were

discussed in Section 6.2.1. Intersection modelling has been completed at upstream and downstream

intersections on the State Highway.


May 2011

An option involving the closure of the Taurima Street/Ruahine Street connection has been modelled. The

effects of this closure have been tested at the Wellington Road/Ruahine Street intersection. The closure of

Taurima Street produces some changes to the delay at the intersection. During the morning peak only

minor changes in delay and queuing were experienced. During the afternoon peak, the intersection LOS

changed from LOS (D) in the preferred option to LOS (E) once Taurima Street was closed. Average delay

increased by around 70% once Taurima Street was closed. Table 6-15 provides a summary of the

intersection performance for the alternative options.

Table 6-16: Alternative Options: Wellington Road intersection summary

Wellington Road/Ruahine

StreetTraffic demand SH Approach DOS

Average

Delay (s)LOS

95th

percentile

back of

queue (m)


No connection at Taurima Wellington Rd E 1.03 101 F 763

Ruahine St 0.96 51 D 694



No connection at Taurima Wellington Rd E 1.00 89 F 491

Ruahine St 0.99 67 E 848


Tunnel Alliance Option 2026 TA AM peak Overall 0.91 6 n/a 0

Wellington Road LILO Wellington Rd E 0.91 6 A 0


Wellington Rd S 0.16 6 n/a 0

Tunnel Alliance Option 2026 TA PM peak Overall 0.80 6 n/a 0

Wellington Road LILO Wellington Rd E 0.80 6 A 0


Wellington Rd S 0.30 6 n/a 0

6.2.7 Kilbirnie Crescent/Wellington Road

Under the ‘Do Minimum’ scenario, the Kilbirnie Crescent intersection is modelled as it is in the existing

situation with the exception of the left turn slip lane on the Kilbirnie approach being signalised. The

intersection operates at capacity in the ‘Do Minimum’ scenario. In the morning peak all approaches are at

or above capacity leading to the intersection operating at a LOS (F). Large queues are formed on the State

Highway approaches. In the afternoon peak, both of the State Highway approaches exceed capacity

resulting in large delay and queue lengths. The intersection operates at a LOS (E) during the afternoon

peak.

Under the Tunnels Alliance option, additional through lanes are included on both the Wellington Road

approaches. The Wellington Road W approach exceeds capacity and operates at a LOS (F) during both the

morning and afternoon period. Large queues (exceeding 600m) are experienced on the Wellington Road

west approach. The intersection as a whole operates at a LOS (F) during the morning and at LOS (E) in the


May 2011

afternoon peak period. The Kilbirnie Crescent left turn experiences high volumes of traffic resulting in

large queues forming. Queuing on this approach reaches 140m. Although this queue can be

accommodated on Kilbirnie Crescent, the intersection design needs to insure queues do not affect the

operation of buses and the viability of bus signal improvements at the intersection.

While the additional capacity of the upgraded intersection does not lead to the expected immediate

improvements in intersection performance, the throughput of traffic is greatly increased. This additional

traffic on the State Highway route represents a large proportion of vehicles which previously made use of

other local roads.

Table 6-17: Kilbirnie Crescent intersection summary


Wellington RoadTraffic demand SH Approach DOS

Average

Delay (s)LOS

95th

percentile

back of

queue (m)

Do Minimum 2026 TA AM peak Overall 1.09 94 F 869

Kilbirnie Cr 1.00 26 C 140

Wellington Rd E 1.00 64 E 527

Hamilton Rd 1.00 64 E 136


Do Minimum 2026 TA PM peak Overall 1.11 91 F 932

Kilbirnie Cr 0.64 25 C 76




Tunnels Alliance Option 2026 TA AM peak Overall 1.06 94 F 653

Kilbirnie Cr 1.00 17 B 141




Tunnels Alliance Option 2026 TA PM peak Overall 1.04 67 E 632

Kilbirnie Cr 0.92 39 D 135




The performance of the Kilbirnie Crescent/Wellington Road intersection has also been assessed following

changes to the layouts of other intersections in the corridor and the effects and changes which are

produced.

The closure of Taurima Street causes slight variations to the operation of the Kilbirnie Crescent/Wellington

Road intersection. LOS changes from LOS (F) in the preferred option to LOS (E) with Taurima Street closed

in the morning peak, but slight increases in DOS and queuing are produced. During the afternoon peak

the LOS remains consistent and average delay and queuing drop slightly.


May 2011

The left in left out arrangement at Wellington Road/Ruahine Street improves intersection performance with

LOS improving in both the morning and afternoon peak periods. Average delay also drops. Table 6-18

provides a summary of the intersection performance for the alternative options.

Table 6-18: Alternative Options: Kilbirnie Crescent intersection summary


Wellington RoadTraffic demand SH Approach DOS

Average

Delay (s)LOS

95th

percentile

back of

queue (m)


No connection at Taurima Kilbirnie Cr 1.00 17 B 142

Wellington Rd E 0.95 56 E 418




No connection at Taurima Kilbirnie Cr 0.86 39 D 145





Wellington Road LILO Kilbirnie Cr 1.00 18 B 141



Wellington Rd W 1.00 46 D 442

Tunnel Alliance Option 2026 TA PM peak Overall 1.00 52 D 578

Wellington Road LILO Kilbirnie Cr 0.79 38 D 138



Wellington Rd W 1.00 73 E 578

6.2.8 Evans Bay Parade/Cobham Drive

For the ‘Do Minimum’ scenario, the Evans Bay Parade intersection remains the same as the existing layout

except for the signalisation of the left turn from the Evans Bay Parade northern approach. The intersection

operates above capacity during both peak periods with large delay, queuing and a LOS (F). The State

Highway approaches are severely over-capacity, which essentially meters the flow of traffic to upstream

intersections.

Under the Tunnels Alliance option, the intersection is upgraded with an additional through lane in the

east-bound and west-bound direction. The additional capacity at the intersection means the intersection

performance improves to LOS (E) during the morning peak and LOS (C) during the afternoon peak. The

average delay at the intersection improves significantly as a result of the improved capacity. The Cobham

Drive approach experiences the largest queues with a 420m queue in the morning peak. During the

afternoon peak, the Wellington Road approach experiences a 400m queue which would interfere with the

Kilbirnie Crescent intersection.


May 2011

Table 6-19: Evans Bay Parade intersection summary

Cobham Drive/Evans Bay

ParadeTraffic demand SH Approach DOS

Average

Delay (s)LOS

95th

percentile

back of

queue (m)

Do Minimum 2026 TA AM peak Overall 1.57 377 F 1885

Evans Bay S 1.56 305 F 651

Cobham Dr 1.57 528 F 1885

Evans Bay N 0.79 19 B 101

Wellington Rd 1.41 391 F 1117.7

Do Minimum 2026 TA PM peak Overall 1.59 264 F 1370.4

Evans Bay S 1.59 282 F 673

Cobham Dr 1.12 175 F 770

Evans Bay N 1.00 19 B 117


Tunnels Alliance Option 2026 TA AM peak Overall 1.00 60 E 417

Evans Bay S 0.74 38 D 62

Cobham Dr 1.00 74 E 417

Evans Bay N 1.00 50 D 176

Wellington Rd 0.92 51 D 323


Evans Bay S 0.96 61 E 175

Cobham Dr 0.97 37 D 207


Wellington Rd 1.00 25 C 287

The performance of the Evans Bay Parade/Cobham Drive intersection has also been assessed following

changes to the layouts of other intersections in the corridor and the effects and changes which are

produced.

The closure of the Taurima Street intersection has little to no effect at the Cobham Drive/Evans Bay Parade

intersection. Slight variations are experienced but these are insignificant in the operation of the

intersection.

The Wellington Road left in left out arrangement means slightly more traffic uses the Cobham Drive/Evans

Bay Parade. Traffic which usually makes use of the Wellington Road/Ruahine Street has to re-route through

Kilbirnie due to the banned right turn at Wellington Road/Ruahine Street. Increases in turning traffic at

Kilbirnie Crescent/Wellington Road intersection result in increased delay. During the afternoon peak the

LOS changes from LOS (C) in the preferred option to LOS (E) with the new alternative Wellington

Road/Ruahine Street intersection. Table 6-19 provides a summary of the intersection performance for the

alternative options.

Table 6-20: Alternative options: Evans Bay Parade intersection summary


May 2011

Cobham Drive/Evans Bay

ParadeTraffic demand SH Approach DOS

Average

Delay (s)LOS

95th

percentile

back of

queue (m)


No connection at Taurima Evans Bay S 0.82 43 D 70

Cobham Dr 1.00 78 E 448

Evans Bay N 1.00 66 E 218

Wellington Rd 0.93 53 D 347

Tunnel Alliance Option 2026 TA PM peak Overall 1.00 32 C 261

No connection at Taurima Evans Bay S 0.96 61 E 175

Cobham Dr 0.97 36 D 204


Wellington Rd 0.99 23 C 261


Wellington Road LILO Evans Bay S 0.87 21 C 62

Cobham Dr 0.99 83 F 69

Evans Bay N 1.00 69 E 39

Wellington Rd 1.00 66 E 61


Wellington Road LILO Evans Bay S 1.04 56 E 219

Cobham Dr 0.78 39 D 233

Evans Bay N 1.00 35 D 114


6.2.9 Corridor as a whole

The operation of the upgraded intersections as part of the Tunnels Alliance option remains largely

consistent with the ‘Do Minimum’ option. The operation of selected intersections improves slightly while

the Goa Street intersection and the Wellington Road intersection perform slightly worse than the ‘Do

Minimum’ scenario.

In the ‘Do Minimum’ case, the throughput of traffic in a west-bound direction is limited at the Cobham

Drive/Evans Bay Parade intersection which operates at capacity. A large proportion of west-bound traffic

turns right onto Evans Bay Parade and proceeds around the bays. The remainder of the corridor remains

saturated with some traffic directing onto Constable Street and along Moxham Avenue.

The Tunnels Alliance option provides significantly more capacity along the State Highway route,

particularly from the Wellington Road/Ruahine Street intersection north. The increased capacity is

generally able to accommodate demand except for a few intersections which exhibit deteriorating LOS.

When compared with the ‘Do Minimum’ scenario, the option provides a significant reduction of traffic

movements using local roads. The route along Oriental Parade experiences a significant reduction in

traffic numbers with around 1500 less vehicle using the route in the morning peak hour and around 1350

less vehicles in the afternoon peak hour or approximately 10,000 vehicles per day. Reductions can also be

observed on Palliser Road and Constable Street as a result of the upgrades on the State Highway. This

reinforces the intended hierarchy of the State Highway.


May 2011

The Tunnels Alliance option produces a corridor which operates at capacity. With optimisation and co-

ordination of the signals, there is a reasonable expectation that both the efficiency and LOS of the State

Highway approaches and the overall intersections would improve. The increased traffic on the State

Highway and reduction in traffic using local roads supports the intended hierarchy of the road network

and will lead to further efficiencies and safety benefits.

Alternative intersection treatments were tested at Wellington Road/Ruahine Street and Taurima

Street/Ruahine Street. These alternative intersection treatments were modelled to assess operational

performance. Upstream and downstream intersections were also assessed to establish what changes these

alternative arrangements made to traffic patterns through the study area.

The Closure of Taurima Street produced minimal change to the majority of the State Highway route. Goa

Street experienced slightly more turning traffic but overall experienced a slight increase in performance.

Wellington Road experienced a slight increase in delay. Evans Bay Parade/Cobham Drive and Kilbirnie

Crescent/Wellington Road experience very little change. Overall the closure of Taurima Street has an

insignificant effect on the other intersections within the corridor. Changes to volumes on local roads can

be seen as discussed in Section 6.2.1 of this report.

The left in left out arrangement at Wellington Road/Ruahine Street has been reported to lead to vehicles

rerouting both through Kilbirnie and along Constable Street/Adelaide Road. The Wellington Road/Ruahine

Street intersection operates well, with minimal delay and queuing. The Goa Street/Ruahine Street

intersection experiences increases in turning traffic and, as a result, increases in delay. Increases in

turning traffic are evident at Kilbirnie Crescent/Wellington Road and Evans Bay Parade/Cobham Drive

intersections as well leading to slight decreases in intersection performance. Changes to volumes on local

roads can be seen as discussed in Section 6.2.1 of this report.

7 Transport economics

A paper11 has been prepared for NZTA that provides the assumptions and results of a preliminary

transport economic assessment of a duplicate tunnel. Three variations of the preferred option have been

tested from a BCR perspective. These include:

• Option with Taurima Street/Ruahine Street restricted to left in

• Option with Taurima Street/Ruahine Street connection completely removed

• Option with Taurima Street Ruahine Street restricted to left in left out and Wellington

Road/Ruahine Street restricted to left in left out.

11 Preliminary benefits for WTA developed Option TA1 (Taurima Street Closed) and TA6 (Taurima Street Open – LILO) –

Opus International Consultants 31 March 2011.


May 2011

This work provides a suitable framework for an economic assessment of the Preferred Option. The process

uses a Wellington SATURN model developed from 2009 validated WTSM models. The future forecasting

model demands are provided by the WTSM model. The high growth WTSM scenario with RoNS project

demands has been used in this project as agreed by NZTA, GWRC and WCC.

Since the initial cost estimate, a quantitative risk analysis has been carried out which led to the estimated

cost of the northern duplicate tunnel and the ‘Do Minimum’ Scheme being revised. These updated costs

have been supplied in the table below.

The SATURN model provides one hour outputs for morning, inter-peak and afternoon peak periods for

2016 and 2026. Travel time (TT) savings and vehicle operating cost (VOC) savings have been extracted

from each of these time periods and ‘annualised’ using a series of accepted factors.

OPUS have calculated crash benefits for the Basin Reserve work in 2009 by construction of a crash model

that covered a large portion of Wellington City south and east of the Terrace Tunnel. This model was

updated for the WTA scheme with additional intersections and links (particularly in Hataitai) added to the

model on the eastern side of the Mount Victoria Tunnel. To calculate ‘Do Minimum’ crash costs, the model

uses the methodology from ‘Method A’ as outlined in Section A6 of the EEM (volume 1). Crash costs for

the option are calculated using a mixture of ‘Method A’ and ‘Method B’ and applying percentage reduction

factors where neither method was appropriate. Analysis of the crash benefits indicates that almost all of

benefits have been generated from a reduction in traffic on Evans Bay Parade.

An assessment of walking and cycling benefits has been undertaken based on demands, issues and desire

lines outlined in the WTA technical note12. Combined walking and cycling benefits have been estimated at

$788k per annum. This is largely based on benefits relating to health and reduction in traffic.

Public transport benefits cannot be assessed using the WTSM or SATURN model. If bus lanes are

implemented on Moxham Avenue, as per WCC plans, there will be minimal impact to public transport

operation and it is considered likely to produce minimal benefits.

An indicative BCR is given in the table below (for further details refer to the technical report). A selection

of sensitivity tests have been produced looking at the effects of a change to TT savings, VOC savings,

expected costs or crash costs. The majority of benefits are generated through TT savings. Sensitivity to

the TT values results in the most significant changes to the BCR.

12 Wellington Tunnels Alliance 2011, Walking and Cycling Demand, 18 February 2011


May 2011

Table 7-1: BCR Summary Option 3A-1 (Pedestrian and Cyclist Benefits included)13

Scenario Estimated Cost $

Costs $ (NPV) Benefits $ (NPV)

Indicative BCR

Do Minimum $13,175,652 12,199,679 131991856

Option with

Taurima left in

left out

$430,300,000 $342,200,000 $161,439,963 0.47

Option with no

connection to

Taurima Street

$430,300,000 $342,200,000 $157,284,686 0.46

Option with

Taurima Street

LILO and

Wellington Road

LILO

$430,300,000 $342,200,000 $141,528,554 0.41

13 Source: Opus technical note: Preliminary benefits for WTA developed Option TA1 (Taurima Street Closed) and TA6

(Taurima Street Open – LILO) – Note: TA6 is equivalent to Option 3A-1


May 2011

8 Further investigation

Following the scoping stage of the Mt Victoria to Cobham Drive study, a preferred option has been

identified. The preferred option is by no means a complete solution. There are a number of areas where

further information is required and sub-options exist. This section outlines areas which require further

information from a traffic and transportation perspective as the project moves into the Scheme

Assessment phase.

8.1.1 Optimisation of signal timings

The Tunnels Alliance option involves a number of signalised intersections in close proximity. It is expected

that the co-ordination of these signals will lead to improved efficiency at each of the intersections within

the study area. The LOS of the State Highway approaches is likely to improve.

At present the intersections have been modelled in isolation using SIDRA to establish the LOS and delay.

Going forward into the Scheme Assessment phase of the project, the signal timings of each of the

intersections will be co-ordinated to reduce delay and queuing at each of the intersections. Once the

signal phases have been optimised and co-ordinated, the model will be re-run to assess the operation.

8.1.2 Taurima Street connection

The preferred option with a northern duplicate parallel tunnel will provide a left in connection to Taurima

Street west approach. The Taurima Street connection has long formed a “Gateway” to the Hataitai

Township and removing movements from the intersection will have a significant impact on Hataitai.

The need to provide a full diverge taper for the left in movement in Taurima Street means the start of the

diverge would need to begin well inside the tunnel bore. Widening of the tunnel bore is likely to be an

expensive exercise. Alternative treatments which do not involve widening the tunnel are being

investigated. Pedestrians and cyclists will also need to cross this left turn slip lane, which would introduce

conflict between vehicles and pedestrian/cyclists.

8.1.3 Pedestrian and cycle path along Ruahine Street/Wellington Road

The proposed shared pedestrian/cycle/service lane is in a conceptual stage. This will need to be

developed in more detail as the project progresses to Scheme Assessment stage. Intersection treatments

will need to be developed for the pedestrians and cycles as well as vehicles using the lane for property

access. Passing areas will be provided to allow passing opportunities for vehicles interacting with

pedestrians and cyclists. This widening is accommodated by removing the planting strip.

In certain locations a grade difference is likely to be established between the access lane and the road

carriageway. In these locations details of retaining walls will need to be included as this may affect the

available width.


May 2011

8.1.4 Parking

Under the preferred option, certain sections of on-street parking are removed from the existing road

layout. While the majority of properties on the route have off-street parking facilities, this parking is used

by other activities such as visitors to the sports facilities in Hataitai Park and Kilbirnie Park.

Options to provide parking facilities for these activities will need to be explored as part of the Scheme

Assessment phase. One such area has been suggested as having the potential to provide for this need.

The Taurima Street west approach, if closed, could provide convenient parking for the Hataitai Park and

Hataitai Village shops.

8.1.5 Alter alignment on Wellington Road/Ruahine Street corner

Under the preferred option, the alignment on the Wellington Road/Ruahine Street corner is designed to

accommodate a 60km/h design speed. Opportunity exists to modify this alignment, either by shifting the

apex of the corner (hence the Wellington Road intersection) or by reducing the design speed of the curve

to minimise the impact on the Town Belt land, urban structure of Hataitai and land acquisition. Alignment

issues are explored in more detail in the Engineering and Construction technical report14. The effect of a

reduced design speed on land acquisition has been explored and drawings have been prepared.

14Wellington Tunnels Alliance, 2011. Mt Victoria to Cobham Drive Scoping Study. Technical Report: Engineering and

Construction.

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