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| Early LGWM "Long Tunnel" option |
I don't tend to do parochial posts on here, but this has my interest, not least because I grew up in the eastern suburbs of Wellington, went to school for some years via Mt Victoria Tunnel, and now once again, live in the eastern suburbs of Wellington after a 20 year absence. I've followed this with interest because for all of my life Mt. Victoria Tunnel has been seen as "inadequate", and it is. This post attempts to explore what might be done, and why...
The raising of the "long tunnel" initially made public under Let's Get Wellington Moving, and revived under the National-led Government since the 2023 General Election is all about a fundamental land transport problem in Wellington that has been a weeping sore since the early 1980s - what should the bypass of Wellington's downtown be?
The problem harks back to three major strategic infrastructure decisions from many years ago:
- Rongotai as the site for Wellington's primary airport (replacing Paraparaumu and Evan's Bay (the latter for flying boats!)
- The Foothills Motorway (in favour of the waterfront motorway proposal).
- Location of Wellington's primary airport at Rongotai.
What this all means is that two key regional facilities are separated from the Hutt Valley, Porirua and Kapiti, as well as Wellington's western and northern suburbs, by central Wellington. The key traffic problem is that the motorway was never finished to a second Mt Victoria Tunnel, as was originally intended.
None of this was a problem for the first few years after the motorway was built, because until 1984 it was not connected to State Highway 1, but after the Ngauranga Interchange was opened (relieving the Hutt Road south of Ngauranga and the waterfront quays), it was clear that having through traffic snake through Te Aro was unsatisfactory.
There are two main arterial routes from the north through Wellington, both of which funnel traffic from the motorway (SH1 and SH2), the Hutt Road (from the northern suburbs of Ngaio and Khandallah mostly), the western suburbs via secondary arterials such as Glenmore Street and Aro Street, towards the south and the west.
These images below depict the volumes of traffic in the AM and PM peak respectively, in 2013 along the main arterial routes, highlighting the urban motorway and SH1 (Vivian Street eastbound and Karo Drive westbound), and along the waterfront route along the Quays, Wakefield and Cable Streets, then Kent and Cambridge Terraces.
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| AM peak traffic Wellington 2013 |
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| PM peak traffic Wellington 2013 |
For Mt Victoria Tunnel 30-40% of traffic at peak times is heading to or from the Terrace Tunnel, noting its importance for providing access to the wider region to and from the airport.
Of course that route as a whole has multiple bottlenecks, particularly southbound with the Terrace Tunnel having only one-lane. Both the Terrace Tunnel and Mt Victoria Tunnel as bottlenecks, result in diversion onto other routes, notably the waterfront as seen below.
Southbound, around 25-30% of traffic on Aotea Quay at peak times is actually heading for either Mt Victoria Tunnel, Adelaide Road or Oriental Parade, it seems likely another few percent is heading towards Taranaki Street as well. Northbound the figure is 15-20% at peak, likely because there are fewer delays westbound through Te Aro as Karo Drive and the Terrace Tunnel both have one more lane (and two fewer traffic signal delays) than the eastbound direction along Vivian Street. The 5-15% of traffic heading for Oriental Parade will be in part for leisure and accessing Roseneath, but is also likely to include substantial traffic going "around the bays" to the airport, notwithstanding that it is around a third longer in distance than using Mt Victoria Tunnel.
In other words, the waterfront route is a backup, and carries between 15 and 30% more traffic than it should because there isn't a reliable bypass to the city. This doesn't just add to congestion along that route, but adds to the cost and hindrance of bringing the city more closely to its harbour. If that proportion of traffic were able to be removed, then there would be scope to convert a lane each way for use for bus rapid transit, but to do so with current traffic volumes would exacerbate congestion elsewhere and add to delays, in the absence of time-of-use road pricing (more on that later).
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| Weekday traffic between Aotea Quay, Mt Victoria Tunnel, Adelaide Road and Oriental Parade |
Defining the problem
Although it would be technically feasible to implement time-of-use road pricing on central Wellington at peak times to reduce traffic entering the central city, it is unlikely to be politically feasible to apply this to through traffic not terminating there, at least as a first step. While motorists are likely to accept road pricing at peak times entering central Wellington, where there are bus and rail options from most parts of the region, such options are not feasible for traffic heading from the Hutt/Porirua towards the airport and hospital, so an inner city cordon, for example, would need to exclude at the very least, SH1 across Te Aro and roads to its south, and possibly also through traffic along the waterfront.
That leaves the inadequacies of the current SH1 corridor very clear:
- Terrace Tunnel bottleneck. One south-bound lane, with it being not technically feasible or safe to implement tidal flow operations (this has been previously investigated).
- Vivian Street bottleneck. Besides being only two-lanes eastbound, the presence of SH1 along Vivian Street adds to the blight in that part of Te Aro, as a major highway route severs Willis, Victoria, Cuba, Taranaki and Tory Streets. The congestion and community severance are not going to be resolved by doing nothing. Karo Drive adds to this westbound, but east of Taranaki Street the Arras Tunnel provides relief.
- Basin Reserve: With major flows from the south to the east and from the east to the west, as well as smaller north-south flows, this roundabout's asymmetric traffic flows have been a bottleneck for decades.
- Mt Victoria Tunnel and approaches from the east: Peak and inter peak, Mt Victoria Tunnel is a bottleneck that backs up to Vivian Street at certain times from the west and north, and backs up along Cobham Drive from the airport eastbound.
The attractiveness of the long tunnel was that it would provide a means for traffic from the east, particularly the airport and Miramar Peninsula, but also Kilbirnie, Lyall Bay and part of Newtown, to access the motorway easily. However, its main limitation (notwithstanding the likely cost) is that it would not provide a solution for through traffic to the southern suburbs, like most of Newtown and Island Bay and notably the hospital. The existing road layouts in Te Aro would have to continue, by and large, to service those areas, unless an expensive interchange were built somewhere in Newtown, which itself would add enormously to the cost of the project.
The main benefit of the long tunnel was that it could be built with minimal disruption, but that is about it...
How Wellington got here.
It was not always going to be that way. The De Leuw Cather report that saw the Foothills Motorway approved (which became the Wellington Urban Motorway) proposed the motorway be completed to a second Mt Victoria Tunnel, to the north of the current tunnel. By and large the motorway that was built to the Hawkestone Street/Tinakori Road off/on ramps resembled the original plan (albeit the flyovers to and from Ngaio Gorge were never built, but the stubs for them remain). However, budget cuts in the early 1970s saw only half of the motorway built south of there, which is why it suddenly goes from three lanes each way to one plus two. Only one Terrace Tunnel was built, where there was meant to be two, and it terminated at Ghuznee Street southbound and Vivian Street.
The original urban motorway would have seen a second Mt. Victoria Tunnel, but would have decimated the Basin Reserve. Te Aro would truly have had a brutalist motorway severing the area, and the cricket ground would have been gone, but that concept was gone within a decade.
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| Original De Leuw Cather Wellington urban motorway Basin Reserve interchange concept. |
In 1972, the Wellington City District Scheme had this option as the revised plan which from the bottom of the image would have seen two-lane each way (extended from two Terrace Tunnels, with a lane gained/lost at the Vivian Street/Ghuznee St one way pair) under Willis and Victoria Streets (Victoria Street had not been extended then), under Cuba Street as well with on and off-ramps at Taranaki Street and Tory/Tasman Street. Curiously the Basin Reserve would have remained two way along Dufferin St , with a second Mt Victoria Tunnel, and the motorway skirting the Basin Reserve.
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| 1972 Wellington Urban Motorway Te Aro extension with duplicate Terrace and Mt Victoria Tunnels |
By the 1980s this had been much more simplified, but with a bridge over Taranaki Street that was seen as too intrusive
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| 1980 Wellington Urban Motorway Arterial Extension concept with elevation over Taranaki St |
Although it was placed under Taranaki Street that didn't exactly help public acceptability with this sort of rendering.
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| 1991 Wellington Urban Motorway trenched (not covered) under Taranaki St |
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| 1994 Tunnellink concept - cut and cover tunnel from Vivian Street to Sussex Street with two-way Basin Bridge to single Mt Victoria Tunnel |
The Inner City Bypass was meant to be a medium-term, second stage of a three stage programme to relieve congestion between the motorway and Mt. Victoria Tunnel (Tunnellink meaning to the third). The first stage was a simple one-way system on existing streets, and the third-stage was meant to be a cut and cover tunnel across Te Aro to the Basin Reserve. The second stage (the status quo) was expected to be adequate for ten years at the most, noting that from the early 1990s Wellington has had a strategy of constraining growth in traffic towards the central city.
Constraining traffic
In the early 1990s, what was then called the "arterial extension" to the Wellington Urban Motorway required Ministerial approval, and the then Minister, Rob Storey, a National MP from a rural electorate, required that action be taken to constrain growth of traffic because of concerns of induced demand. The business case for the project estimated an annual traffic growth factor of 2%. The response was the introduction of the Coupon Parking Scheme, on unmetered car parks close to central Wellington, which Wellington City Council estimated would constrain traffic growth to 0.5% (along with introduction of limits to car parks for all new developments and abolition of the minimum car park requirement). At the time, Transit New Zealand as the land transport funding agency and state highway manager, recognised this, but the impact on the business case for the project was to knock it back. In effect, demand management delayed the need for the project.
Tunnellink and the three stages
In the 1990s, there was some controversy over the proposed motorway extension, although there was always a clear majority of city councillors in favour of the project. Yet the key issue was funding at a time when Government only allowed enough funding to be made available for land transport projects with a benefit/cost ratio of at least 5:1 (lowered to 4:1 in 1998 onwards), for a project that, at the time, had a BCR of 2.6 (although an optimistic scenario saw it raised to 3.2).
With the change in government in 1999, there was quite a fight to be had as the Clark Government relied on the Greens for confidence and supply, and also agreed to consult the Greens on transport policy. The Greens demanded that the Inner City Bypass be stopped. At the time, the legislation did not allow the Minister of Transport to direct the then, independent funding agency, Transfund New Zealand, to approve or block any projects. In truth, the Clark Government was in favour of the project, and it received approval, although opponents used every legal avenue to delay it, so that it took over a decade from the initial approval of the concept for it to finally get built.
Of course by that time Transit New Zealand, as the state highway manager, had abandoned hope that any additional project would ever get approved across Te Aro, so had shelved the Tunnellink idea and refocused on what would be needed next - and that was the Basin Reserve.
That became the next problem,
Basin Reserve
The Inner City Bypass made a useful difference to traffic flow across the city. Particularly westbound, having shifted traffic a couple of blocks south, and with three lanes, queues towards the Basin Reserve were eased, and delays reduced. Eastbound, Vivian Street flowed more efficiently as a single one way route than the dog-legged route via Ghuznee Street, but the Terrace Tunnel remained a major bottleneck. By the 2010s, although there were now budget surpluses and governments of both hues committing to more funding for roads, a second Terrace Tunnel still seemed some years away. The focus shifted to the Basin Reserve, as it would (and still does) back traffic up in both directions. As the Basin is effectively a major intersection with heavy traffic flows east-west and lesser flows north-south, the case for some grade-separation of those flows has always existed.
From there came the Ngauranga to Airport study and the Basin Bridge project. The Basin Bridge started as a project to take westbound traffic out of circulating around the Basin Reserve from Mt Victoria Tunnel, and towards Buckle Street. Indeed, the 2012 depiction essentially envisaged it feeding the Arras Tunnel. The effect of this would have been to significantly change the traffic light phasing around the Basin Reserve to ease flows to and from Adelaide Road, but the backlash, even though the bridge was essentially clear of the Basin (and designed with a 50 km/h limit) was considerable from Mt Victoria Residents. This was also fuelled by many who opposed the Inner City Bypass, seeing this as just another "motorway" to oppose.
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| 2012 one-way Basin Bridge concept to existing Mt Victoria Tunnel only |
Perhaps the biggest limitation of this proposal was that it offered little scope to support relocating State Highway 1 south away from Vivian Street to enable two-way traffic. It solved "half" of the problem and offered no real vision for what a decent bypass of Wellington should look like and how it should function. Hence it would also not satisfactorily support a second Mt Victoria Tunnel, as that tunnel would be constrained by the capacity of Kent Terrace and Vivian Street. The Basin Bridge would have been short-sighted.
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| 2012 one-way Basin Bridge concept to existing Mt Victoria Tunnel only from west |
The history behind the Basin Bridge and the Environment Court rejecting it, largely due to objections of local residents is the embryo of Let's Get Wellington Moving. As that emerged, in part to try to find a way forward, another concept came up, enabling two-way traffic to bypass the Basin.
This concept enabled a future of a trenched bypass through Te Aro feeding onto a bridge towards a second Mt Victoria Tunnel, with an at grade route close to the Basin, with Sussex Street widened and built over the new road towards a widened Cambridge Terrace. This would mean two way traffic from Adelaide Road circulating over Sussex Street abandoning the Basin roundabout, although it was not perfect. It offered no access from Mt Victoria Tunnel to Cambridge Terrace with only a rudimentary ramp for access to the schools at the Basin, although that could easily be fixed by making the Dufferin Street ramp larger and retaining "around the Basin access" to Sussex St. You can see the dotted line for an eastbound cut and cover tunnel from the motorway with a ramp to Cambridge Tce and continuing to Mt Victoria Tunnel, but again there remains a flaw. Access from THAT tunnel to Adelaide Road doesn't exist. Without direct access from the bypass to Adelaide Road, the route misses a key connection, so this is not a solution.
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| 2018 alternative Basin Bridge concept two way |
So a whole host of options emerged, as Let's Get Wellington Moving saw its objectives amended, largely reducing the value placed on reducing traffic congestion, and more focused on modal shift and encouraging active modes and public transport. The options illustrated below demonstrated this as none would support moving SH1 off of Vivian Street, and enable a second Mt Victoria Tunnel for more general traffic capacity. That of course was not the objective in the latter years of Let's Get Wellington Moving.
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| Let's Get Wellington Moving Basin options |
For what it's worth, I think the right solution is to enable what is depicted below from an early concept in LGWM to shift SH1 to the Karo Drive corridor in a trench to connect to a future proofed Basin Reserve grade separation.
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| Long term option for cut and cover bypass across Te Aro |
and no, tunnelling too deep on the north side of the Basin Reserve isn't an option. There is a stream already running under there and the geology is soft (it isn't called "Basin" for nothing, as the land was uplifted in the 1878 earthquake from what was then considered to be a possible location for docks). So the Basin Reserve either needs to be bypassed far away (Long Tunnel), be bridged over somehow (or with a shallow trench and lower bridge), or be left alone. However, moving SH1 into a trench to its west, is not going to be worth doing until a solution is found for the Basin, and there is likely to need to be some engineering creativity involved in achieving that. Otherwise there would be a congested at grade intersection.
Maybe this sort of elegance is needed to make it acceptable? Bearing in mind it would need to be a two way bridge, be lower at the western end (as Sussex Street on a bridge over the end of it would make sense), and then assuming it isn't going to be light rail, there is space for bus rapid transit to go around the Basin in both directions to and from Adelaide Road (and the duplicated Mt Victoria Tunnel).
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| 2008 indicative Basin Bridge concept from north |
Mt Victoria Tunnel
East of the Basin Reserve the options become clearer. In 2011, a range of options were considered, including tunnels either side of the existing one, and longer ones from Wellington Road at various points, and new bus tunnels.
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| Mt Victoria Tunnel duplication options considered 2016 |
The conclusion was clear:
and it was depicted as follows from Wellington Road to the Basin Reserve
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| Preferred Mt Victoria Tunnel, Ruahine St and Wellington Rd duplication concept 2017 before cancellation under LGWM |
Funding and pricing
Tolls aren't likely to be much use for this option, not least because the key point of doing this project is to take traffic off of alternative routes. Tolling the existing and a new Mt Victoria Tunnel (unlike the long tunnel) would likely see Newtown and the Evans Bay/Oriental Parade routes get filled. Unlike tolling more rural segments of highway, the costs of less traffic through the tolled routes are more likely to be born in higher externalities in built up areas.
However, time-of-use pricing designed to shift demand during peak times entering the central city (to the east and north of SH1) could certainly be used, to reduce congestion entering Wellington city and free up capacity for traffic bypassing the city. It could also be used to help fund a bypass, as this is what happened in Oslo with implementation of its toll rings through Oslo Package 1.
The amenity value in removing perhaps half of the traffic from Vivian Street (and on what remains of a surface route were Karo Drive now is), and removing around a quarter of traffic off of the waterfront route would be considerable. As such, this whole project needs to be seen as much as an urban amenity and redevelopment project, as a road project. It would enable longer crossing times across the Quays and the Quays to be more oriented towards local access. It would help increase connections by bus, foot and cycling across this route to and from the city, and help to revitalise Te Aro with a significant reduction in traffic. Oslo saw this happen when it built a bypass tunnel under its central city.
Bear in mind the long tunnel would have speeded up travel from the airport to the motorway, but would not have had the same scale of impact on local amenity because it would not have served as much traffic as the more localised option across Te Aro.
What matters is cost, although clearly this all could be done in stages, unlike the long tunnel. This enables costs to be better managed, and for benefits to be realised much more quickly.
Mt Victoria Tunnel and the widening to the east could be done in one stage. Other stages include grade-separating the Basin Reserve, trenching across Te Aro and finally, a second Terrace Tunnel (which would be relatively easy to build, as all of the land is reserved and part of the approaches were built before being cancelled).
It could all be done supported by time-of-use road pricing to manage demand and help support the funding of it, and the sequencing is important. A second Mt Victoria Tunnel would make some difference, but without a Basin Reserve upgrade would see traffic backing up through the westbound tunnel from the Basin. A second Terrace Tunnel without a trenched route across Te Aro would not achieve much beyond some shortening of queues. The trenched route would be highly disruptive while being built, but without a Basin upgrade would see big queues eastbound.
One thing seems likely, the long tunnel looks like it is a non-starter, but a second Mt Victoria Tunnel looks like it could proceed, more quickly than anything else at this stage. Wellington could do worse than proceed with those plans, which include an upgraded cycling and pedestrian route in the new tunnel, as a first step, while more time and money is spent working out how to take that traffic between there and the Terrace Tunnel.
Conclusion
The rational economic answer would be to introduce time-of-use road pricing for entering central Wellington and then seeing what the traffic looks like, but it seems highly unlikely that this could obtain the political and public support necessary to proceed. So a second best is to implement road pricing to help pay for a project that has, as a fair proportion of its benefits, public amenity and development of the city by removing through traffic. To do that requires extra capacity at the Terrace Tunnel, Mt Victoria Tunnel and across Te Aro between them.
It would be a significant step forward not just for general traffic for both people and freight between the airport and the region, but also the hospital and eastern and southern suburbs, and the region, but for public transport, cycling and walking to and from the city, and for the development of Wellington as a destination. The latter comes from it being not just easier to get to and from the airport, but by removing the blight of through traffic in Te Aro and making the waterfront a destination that is not severed by a primary arterial highway.
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