Failure to assess all the impacts - Newtown to City Connections Part One

Background

There is a lot of talk about “evidence-based” transport policy, typically as a criticism of some of the policies of the current Minister of Transport, Hon. Simeon Brown.  Certainly the more evidence behind public policy the better, although that evidence should be carefully refined and assessed as to its relevance. Unfortunately, there are instances of what appears to be either deliberate or negligent failure to gather evidence to support highly contentious policy initiatives. I’m going to highlight one that deserves greater consideration, and which as a result, both undermines the case for the initiative (because the omission of evidence gives reasons to doubt its effectiveness) and also calls into question the objectives behind the initiative.  The case study is the introduction of cycle lanes and bus lanes in Wellington on a key southern corridor.

Newtown to City Connections

Depiction of the southern corridor between hospital and Basin Reserve and Basin and Wakefield Street

The project is titled “Newtown to City Connections” and Wellington City Council (WCC) released a report on 19 September 2024 called the “Monitoring and Evaluation Report” (“the Report”). The project consists of:

• 24/7 bus lanes installed northbound on Riddiford Street from Hall Street to John Street.

• 24/7 bus lanes installed in both directions on Adelaide Road from John Street to Rugby Street.

• Extending bus lane operating hours on Cambridge and Kent Terraces to/from the Basin Reserve to 7 days a week 0700-1900.

• Separated cycle lanes installed on the Riddiford and Adelaide Road sections, and installation of a two-way cycleway on Cambridge Terrace and a short segment of Kent Terrace between the Basin Reserve and Wakefield Street.

What isn’t mentioned is that it also includes removal of the following:

• Halving of general traffic capacity on Riddiford Street to Hall Street northbound (but not southbound which retains two lanes for all traffic)

• Removal of carparks on Riddiford Street western side and on Adelaide Road on both sides

• Reduction of general traffic capacity on Cambridge Tce by 50-66% depending on the time of day

• Reduction of general traffic capacity on Kent Terrace from Cable Street to Elizabeth Street by a third.

The image below illustrates how two general traffic lanes and parking were altered to one general traffic lane, a 24/7 bus lane and a cycle lane on Riddiford Street northbound.

Before and after of northbound cycle and 24/7 bus lanes on Riddiford Street

The project was only $4.6m in cost because it was largely about signs and lines and some physical barriers on the road network, along with some new traffic signals, although one might question the quality of road lining in places (old road lines are still highly visible and confusing), but that is beside the point. It is touted as a low cost roadspace reallocation from general traffic towards buses and bicycles. The real issue around costs is not the construction costs, but the trade off of costs and benefits between all road users, unfortunately there hasn't been enough of an evaluation of impacts (or if there has, it has not been published).

The case for implementing such reallocations is typically about giving priority to some modes over others, and for cyclists primarily to address safety issues, in particular preventing serious and fatal crashes. The effect of the latter will be to encourage more to cycle, hopefully reducing congestion from car driving but also in some cases overcrowding on public transport (London was primarily about the latter).

 The problems to be solved and expected outcomes for such a project should be:

• Reducing traffic congestion, travel times and consequently improving trip reliability for buses.

• Reducing the incidence of fatal and serious cycling accidents.

• Reducing general traffic congestion by inducing modal shift from car driving to bus riding or cycling sufficient to offset any negative impacts on general traffic.

• Increasing the attractiveness of the corridors for pedestrians and retail/service/hospitality oriented businesses to offset any negative impacts of removal of carparks.

Unfortunately the Report published by WCC appears to have only provided some partial assessment of impacts and leaves some big questions unanswered. These are questions that should be answered.  It should also be answered as to why a complete picture has not been provided.

This blogpost is in two parts. 

This first part focuses on the critical issues that are not adequately addressed in the Report and what WCC should do about it. The second is a review of the report contents itself, which are frankly not particularly enlightening.

Key issues

As the cost of this project in capital terms is relatively low, compared to other road infrastructure works, the big questions are the ones noted in the bullets above.  Given the project is primarily about reallocating road space from moving general traffic and parked vehicles, towards buses and cycling, it ought to, at a bare minimum, result in a total reduction in transport user costs and hopefully reduce negative externalities, so that the value of the reduction of those costs is greater than the capital costs of the project. In reality, it should mean those facing any increases in costs (e.g, those looking for a car park or general traffic more generally) should have those costs more than offset by the value of the benefits to those facing reductions in costs, as well as society as a whole through lower negative externalities. 

It should work like this:

• Travel times for buses should be shorter or less variable (so that timetables are met reliably) compared to before, and this should be especially so outside peak times (as there were already peak bus lanes on two out of three of the road segments). 

• Travel times for general traffic should ideally be no worse than before as a minimum (because the reallocated road space was underutilised), and ideally better (if modal shift occurs).

• The incidence of fatal and serious injury crashes should drop, particularly for cyclists given the focus of the project, but also crashes for pedestrians and motor vehicle (including bus) occupants should at least be no worse, and ideally be better.

• Counts of pedestrians along the corridor should increase, offsetting the loss of car parks, as a broad proxy for enhanced opportunities for retail.

Unfortunately, there is only sparse data on any of this, and none on some of these factors.

What do we know?

1. Travel times for buses have increased (see the Figure below from The Report). This is attributed to increase boardings, but although data on bus patronage indicates a large increase over two years, this also parallels growth in demand across the network due to the end of the pandemic. January-July 2022 the country was in Red and Orange status under the traffic light system, so a 69% increase in patronage is not surprising, particularly as in January-July 2022 some weeks saw around 10% of the Number 1 bus route not even operating.  Introducing bus lanes should more than offset increased boardings, but even then, why wasn’t data used to compare patronage and travel times pre-pandemic? 

2. In the eight years from 2016 until 2023, there were no fatal crashes (see the Figure below from The Report), in three years no serious crashes and in two years one, in two years two and in one year three serious crashes. In no year were there more than nine minor crashes.There has been no discernible impact on injury/fatal crashes at all from the works, but clearly perceptions of safety for cyclists have improved understandably, but not for other road users.

What don’t we know?

1. There is no data reported on travel times for general traffic. It would seem extraordinary that travel times have not increased, particularly on Riddiford Street and Cambridge Terrace, but WCC is either not collecting that data or not reporting on it. If there has been no increase or a decrease then this should be something to show off, but if it has increased significantly, then this is a cost on not just car traffic, but also commercial traffic for deliveries and business traffic. 

2. There is no data on any changes in modal use of the corridors. This would ideally require surveying both cycling and bus users, but also count pedestrians and car traffic. If there was modal shift, it would be worth reporting, but if not then what is the benefit of reallocating road space?

3. There is no data on pedestrian counts, which might be a useful measure of people accessing retail or service businesses by modes other than cars, given the removal of car parks.

So the actual impacts of this project, in the whole, are unclear. At best it appears it increased cycling trips, but we don’t know where they came from. It is unclear if it has impacted on bus trips, but we don’t know if they were a shift by mode or new trips.

At worst, it is plausible that the bus lanes had no impact on bus travel times, because they two of the three improvements were extending hours beyond peak times, or (as it more plausible) the queues of general traffic northbound on Rintoul and Riddiford Streets due to the congestion of the single northbound lane (on a road with two southbound lanes) have more than offset the benefits of the bus lane. It's fairly obvious that a road with only one northbound lane and two southbound lanes for general traffic would suffer congestion northbound.

Indeed at 4.40pm on a Friday, this screenshot from Google Maps illustrates this. Traffic is slow on the northbound side backing up to the two lane northbound segment from Rintoul to Hall Street and further into Riddiford Street further south.

Indeed the intersection that the Report cites as having much higher cycling traffic has considerable congestion (see above), including in the directions with no bus lanes. If this work has not saved time for buses, then questions need to be asked as to the impacts on general traffic (and as a result, local air quality). Clearly there is not enough modal shift onto cycling to offset this.

It is clearly plausible that the travel times for general traffic on Riddiford Street, Adelaide Road and Cambridge Terrace have worsened with the reallocation of road space. In other words, congestion has increased and possibly noxious emissions as well. It may also be plausible that the reduction in car parks has negatively impacted local businesses, but this is much less clear, given there are so many factors affecting these businesses.

Conclusion

There are significant gaps in analysis that make it not at all possible to assess whether this project has made a net positive contribution to the costs of travel along this corridor for all users or indeed the costs to society as a whole.

It is clear that cyclists have benefited and there is more cycling, but it is unclear whether these are just new trips, or people have shifted from driving cars (or walking, or riding buses). WCC didn’t collect that data.

Pedestrians do not seem to have benefited at all (indeed if congestion is worse, it may have worsened air quality for them). Bus passengers may or may not have benefited, as travel times haven’t improved. General traffic almost certainly has lost, so this means everyone travelling by car, but also freight and commercial traffic (e.g. plumbers) and this includes traffic to and from the hospital. It may also have impacted on retail, but there isn’t enough evidence on this. 

Surely advocates of this sort of project ought to also advocate for more data to be collected. If this project is to be defended, it should be on the basis that the benefits of it are worth the costs.  If worsening general traffic congestion is seen as a good thing, then the advocates should defend this position and say it is part of a process to encourage behaviour change.  

Wellington has multiple projects like this (see Thorndon Quay, Karori, Thorndon). There is a real risk more of these projects won't proceed at all, or may even be reversed if there is not full transparency as to the benefits and costs of these projects. Failure to provide this fuels an unnecessary culture war, as advocates regard critics as wanting "cyclists killed" or "denying climate change", while opponents see it as a "war on cars" that "benefits a tiny minority".

I would hope that there might be some consistent, clear and open evaluation of impacts that is transparent about different impacts on different network users.  Concealing or failing to evaluate impacts on some road users (particularly those who motoring taxes help pay for these projects) is quite simply very poor public policy, and does not help promote public acceptability or trust in decision makers.

If Wellington, or indeed any city, wants to advance projects that controversially take road space from some road users to benefit others, there should be robust analysis underpinning it. Unfortunately it seems unlikely that the Newtown to City Connection project has that at all.

Wellington and the "long tunnel"

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.

AM peak traffic Wellington 2013

 

PM peak traffic Wellington 2013

Between 25 and 30% of traffic exiting and entering the motorway at the Terrace Tunnel is coming from or heading to the Mt Victoria Tunnel, so is using the streets in Te Aro to bypass the downtown area. Another 5-25% of traffic at peak times each is heading onto or coming from Taranaki Street and Adelaide Road south of SH1, indicating that the vast majority of Terrace Tunnel traffic is travelling to and from the southern and eastern suburbs, not Te Aro and the CBD. 

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).

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.

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.

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

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.

1991 Wellington Urban Motorway trenched (not covered) under Taranaki St

So, the entire section from Willis Street to the Basin Reserve was to be put into a cut and cover tunnel, called Tunnellink. Going east there would be one on-ramp at Victoria Street and another from Kent Terrace to the Mt Victoria Tunnel, with an off-ramp to Cambridge and Kent Terrace for southbound traffic to Newtown. Going west, one onramp from the Basin Reserve and an offramp at Victoria Street were all, as the road was primarily designed for through traffic.

1994 Tunnellink concept - cut and cover tunnel from Vivian Street to Sussex Street with two-way Basin Bridge to single Mt Victoria Tunnel

This did not proceed, as the funding constraints in the 1990s saw the newly named "Wellington Inner City Bypass" built in 2007, essentially widening and extending Arthur Street west to Willis Street, so that the northbound on-ramp could be relocated a block south, and Vivian Street became the southbound off-ramp as a one-way pair. The Arras Tunnel, built solely to enable the War Memorial Park, provided a wider route with the removal of Buckle Street and the Tory Street westbound intersection.

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.

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.

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.

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. 

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.  

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).

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.

Mt Victoria Tunnel duplication options considered 2016

The conclusion was clear:

and it was depicted as follows from Wellington Road to the Basin Reserve

Preferred Mt Victoria Tunnel, Ruahine St and Wellington Rd duplication concept 2017 before cancellation under LGWM

It seems likely that this is the most cost efficient option to proceed, as long as the decision on the Basin Reserve can address issues around visual impact and noise.

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.