We believe the harbour crossing should be public transport and active only bridge. Here are a few key reasons why.

Why another road crossing is dumb idea

This is something we’ve talked about a number of times before. The most recent plan for another harbour crossing comes from 2011 and in a nutshell, the new crossing would be for traffic travelling past the city centre and the existing Harbour Bridge would become a glorified off-ramp.

There are two logical outcomes from this and neither are good.

1. Stuffs the city and the North Shore

Turning the current Harbour Bridge and approach motorways into an off-ramp only serving city centre trips would be like turning a firehose of traffic on the city centre. That’s because currently, most of the traffic crossing the bridge isn’t heading to the city. Of the approximately 85,000 vehicles that travel southbound daily, only about 25% exit at Fanshawe St (14%) or Cook St (11%). Even if you included Shelly Beach Rd that only adds another 9%. Freeing up so much capacity would encourage people who might currently catch the bus or ferry to return to their cars and that would swamp city centre streets.

This is of course completely at odds with what Auckland has been striving for, although not always as successfully or as fast as we’d like to see. Auckland’s vision is for the city centre to be a more people friendly place, meaning more emphasis put on walking, cycling and urban design and less on moving large metal boxes. That’s much harder to do when at the same time you’re encouraging more people to drive to the city.

The same thing applies on the North Shore, north of where the crossings join. Many of the local roads are already jammed around peak times and this will just exacerbate the problem.

2. Doesn’t add any capacity

In the alternative version, we build the new motorway crossing and in order not to cause the issues mentioned above, we reduce the car capacity on the existing bridge through dedicated bus lanes, bike lanes (perhaps with Skypath dedicated to waking only) or other measures. So in this case we’d be spending $5 billion or more to add no car capacity and only slightly improve buses. This raises the question of why not just use that money to build a dedicated PT crossing?

On top of these two issues there are other things to consider too. For example, the current plans for another crossing have been estimated at more than $5 billion but that is only for the crossing itself between Esmonde and the city. On top of that there would almost certainly need to be a significant widening of the motorway north of Esmonde as far as Constellation – much like how the SH16 causeway was widened as part of Waterview. That won’t come cheap.

Then there is the resilience argument, that having another crossing provides a form of infrastructure security in case something goes wrong. But it’s worth thinking through what this actually means. The current plans have no connection between the bridge and possible tunnel. That means should something happen on either one, the ‘resilience’ option, or even just when maintenance is happening, is to divert all that motorway traffic back through the city centre.

It’s worth noting that the original Auckland Transport Alignment Project (ATAP) report pushed back the timeframe for another road crossing till the 3rd decade (2038-2048) and said this:

Our analysis has shown that in the short and medium term, access to and from the North Shore is not as constrained as for other parts of Auckland (particularly the west and south). While an additional crossing could significantly improve access to/from the North Shore, it does not appear to improve congestion on either side of the crossing. Forecast growth in freight demand indicates that without a new crossing, some restrictions for heavy vehicles using the Auckland Harbour Bridge may be needed by around 2030 to ensure the longevity of the Harbour Bridge. However, economic analysis showed that the costs of any restrictions are likely to have a minimal impact compared with the costs of a new crossing. Heavy vehicles will continue to be monitored and managed to keep motorists and freight moving across the Auckland Harbour Bridge

Why a PT only crossing is a good idea

While a new road crossing doesn’t make any sense, a dedicated PT crossing does and meets or enables all of the goals stated for why we need a new crossing. Here are a few reasons why

Provides the needed resilience

The need for resilience is the strongest argument for another crossing but that doesn’t have to mean duplicating our existing infrastructure with more of the same. There is also value in providing resilience through having alternatives – we already see almost daily that a crash or breakdown in just the wrong spot can seemingly bring half the motorway and local road network to its knees, same goes for the rail network.

By having a PT only crossing we ensure that not as many people are impacted by disruption on any one mode and that our transport networks complement each other.

One of the best examples of alternatives providing resilience is the 1980 Loma Prieta earthquake in San Francisco. When part of the Bay Bridge collapsed, cutting off an important connection between Oakland and San Francisco, some of the impact was able to be reduced thanks to the BART system which runs under part of the bridge.

Provides the needed capacity

A few years ago, the NZTA provided me with some hourly data on the usage of the Harbour Bridge. From that, I was able to put this graph together showing that traffic volumes peak at 8,000-9,000 vehicles per hour – during which time five of the bridge’s eight lanes are dedicated to the peak direction.

The actual number of people crossing the bridge will be higher than this though as at peak times, 30-40% of people are crossing are doing so on a bus. This would probably put the number up around 11-12k. By comparison, a single light rail line could move almost 11,000 people per hour, essentially doubling the peak hour capacity of the existing bridge.

Aligns with policy

A dedicate PT crossing also fits in best with the current stated goals of Auckland and the government.

The latest version of the Auckland Plan, Auckland’s long term spatial plan, has a section dedicated to transport and access. It includes as one of it’s focus areas to “Make walking, cycling and public transport preferred choices for many more Aucklanders“. The other Directions and Focus Areas would also support a PT crossing.

Then there’s the most recently released version of ATAP that notes more work needs to be done on a future harbour crossing but does suggest there needs to be “flexibility for rapid transit and road to potentially be delivered in separate tunnels at separate times“. In addition, in the section on future Rapid Transit priorities it includes this comment about the Northern Corridor

Projected future demand on this corridor is high and detailed investigation by Auckland Transport suggests upgrading the Northern Busway to a higher capacity mode (likely to be light rail) may be required by the mid-2030s, earlier than previously anticipated. This would require a new rapid transit crossing of the Waitematā Harbour on an alignment that connects with the City-Airport light rail corridor at Wynyard Quarter.

This is also why the combined tunnel, as shown by the NZTA in the first graphic, isn’t a good idea.

Why a bridge and not a tunnel

It is currently envisioned that any new crossing would be in the form of a tunnel. We also believe the form of any future crossing should be revisited and that bridge would provide a better option.

A good example of what we’re thinking about is the Tilikum Crossing in Portland. Opened in 2015, it was built to carry light rail, buses, streetcars, cyclists and pedestrians over the Willamette River. The fact that buses can also use the bridge could be useful here too, if for nothing else than as a staging option until light rail can be extended all the way up the busway.

Here are some of the reasons for that.

Better walking and cycling included

Skypath is a fantastic project and is needed as soon as possible to address 60 years of active mode neglect on the existing bridge. But a PT bridge across the harbour could also include improved walking and cycling facilities – you can never have too many of them. It also wouldn’t make Skypath obsolete as which crossing to use could depend on where you’re coming from, where you’re going to and would depend on where the new bridge landed.

The View

If there’s one thing I never get tired of when commuting home from the North Shore it’s the view of the city that unfolds in-front of you as the bus passes under Esmonde Rd and heads along the edge of Shoal Bay, all the way to the other side of the Harbour. The view is even better from the top floor of a double decker bus.

There are probably not too many PT commutes that can compete with that, and sitting on a bus, or future train, actually gives you time to enjoy it. Why would we want to hide that away in a tunnel?

Extra capacity

As mentioned earlier, a single light rail line could carry as many people across the harbour as the current bridge does today. However we believe a bridge also gives us the opportunity to think about providing even more capacity by allowing for up to four tracks as part of the design (two each way). This is something that would require entirely new tunnels to be bored at huge cost if tunnel options were chosen.

Easier to construct

Bridges are easier and faster to construct than tunnels. The last work released publicly for the motorway options showed a bridge taking 1-2 years less time to construct. One of the biggest challenges with the bridge option over a tunnel would likely be to do with consents in and around the harbour, but given the what’s happening with the America’s Cup and that the NZTA didn’t seem too bothered by coastal issues with the East-West Link, this doesn’t seem like it should be too hard for them to address.

The Cost

There’s one final and not insignificant reason to consider a bridge based option, the cost. We don’t know exactly what a PT and active only bridge would cost but it would be:

cheaper than a motorway bridge, especially on a per capacity basis.

much cheaper than a tunnel.

Let’s look at each of those quickly.

Compared to a Motorway bridge

A road bridge would be at least six lanes wide, plus the extra space for walking and cycling. The designs created during the last study showed a bridge approximate 47m wide and that included only 3m walking and cycling paths on each side.

By comparison, the Tilikum Crossing is just 23m wide and that includes waking and cycling paths on each side at 4.3m wide. In short, a narrower bridge should also mean a cheaper bridge.

In addition to the width, connecting it into Wynyard should also help make for a cheaper bridge.

Compared to a tunnel

Tunnels are always going to be more expensive than a bridge. As a comparison, in the last AWHC study, the bridge option was estimated to cost $3.9 billion whilst the tunnel option would cost $5.3 billion. So not only did the tunnels cost more, they did less as didn’t include walking and cycling options. We’d expect similar kinds of cost differences between a rail only tunnel or bridge.

We can redefine our harbour

Bridges all over the world are used to define cities and multiple bridges, if designed right, could further enhance Auckland’s. The biggest challenge with this is coming up with the right design as what ever is proposed is going to be hotly debated.

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