By now I’m sure most have seen the news about the Auckland Harbour Bridge being damaged after a 127 km/h gust of wind blew over two trucks, including one that hit a load-bearing upright strut on the superstructure.
As is always the case these days it seems, it was even caught on camera.
Here's the video, rotated. (Don't know who was the original source, sorry) pic.twitter.com/nhMjmOat8G
— Nat Torkington (@gnat) September 18, 2020
This has resulted in the centre four lanes of the bridge being closed to all traffic, half it’s normal capacity and even less in peak times.
“A temporary fix to re-open lanes may be possible in a few days but a permanent repair is weeks away. We’re working on both and working as quickly as we can”
This adds to an already difficult time with the city’s transport infrastructure with the rail network being slowed and partially shut down due to worn our rails. I think there are both short and long term actions we need as a result of from this bridge disruption.
The NZTA are calling on people to work from home and/or avoid the bridge, but also alternative routes like the Northwestern.
“While the Auckland Harbour Bridge is at half its usual capacity there are also significant knock on effects across the transport network, with additional vehicles now switching to the Western Ring Route,” says Waka Kotahi Senior Journey Manager Neil Walker.
“We ask people to consider working from home if possible or using public transport instead of taking the car. If you must travel, avoid peak times in the morning and evening and allow extra time for your journey. Heavy congestion and delays are expected on both sides of the bridge as well as other state highways and local roads.”
The Northern Busway will be operating and buses are safe to use the clip on lanes, however buses will be delayed as they join the queues to cross the bridge, so passengers should plan ahead and allow extra time for their journey.
One of the tricky things is that many of the buses that might have otherwise been able to be used are not available because they’re needed as rail replacement buses. Even so, AT say:
We will be increasing the frequency of bus services outside of peak hours so you can take advantage of our 30% off-peak fare discount. Ferries are operating as usual and have spare seating capacity.
We looked into how many passengers we can carry on bus routes that go across the Harbour Bridge and found that:
- For a Monday morning inbound to the city, 7:00am to 8:59am:
- The Northern busway has 7000 seats available with normal service.
- Onewa Road has 2500 seats available with normal service.
- For Monday afternoon outbound from the city, 4:00pm to 5:59pm:
- The Northern busway has 6500 seats available with normal service.
- Onewa Road has 3000 seats available with normal service.
These numbers are for seats only and there is room for about 10% more people when standing. North Shore ferries will be using the largest vessels available, and additional services are on stand-by.
As is noted above, the issue with this is that buses will be caught in congestion as they approach the bridge. While the bridge is already significantly down on capacity, perhaps now is when they should be adding some bus lanes to the bridge. The idea being to really make the PT option work as smoothly as possible to help encourage as many people as possible to use it.
In addition, the NZTA should be adding a Northbound bus lane through St Mary’s Bay. There should be enough space for one from the Fanshawe St onramp through to about the Curran St onramp, which is where the clip-on and centre lanes start to diverge. This would allow those buses to skip about 1km of traffic and frankly should have been done as part of the works about a decade or so ago.
Perhaps AT also need to put in some temporary cycleways on all approaches to busway stations to make it easier to get to them.
Firstly it’s important that we don’t over-react. Already there’ve been plenty of suggestions that this proves we need another harbour crossing (for cars). When we think about the long-term implications the first thing we should remember is that this is a very rare event. It’s so rare that it’s the first time it’s happened in 60 years. Something that causes a few weeks of disruption every 60 years, no matter how frustrating it is at the time, is not justification for spending billions of dollars on duplicate infrastructure.
Resiliency is often cited as the main argument for building another road crossing but even if we already had it, it wouldn’t have prevented chaos. Here’s why:
Resilience ≠ Capacity
Having an alternative to the bridge and SH1 was one of the key arguments behind the building of the Western Ring Route (WRR). In fact, the NZTA’s project page says this about it:
Once complete, the Western Ring Route will be an alternative to Auckland’s State Highway 1, linking Manukau, Auckland, Waitakere and the North Shore, improving network resilience, travel time reliability and bus shoulder lanes, and upgrading cycleway and pedestrian facilities.
The WRR does provide an alternative route but it doesn’t and can’t provide enough capacity to cope with the level of demand that it normally handles as well as the bridge traffic. We saw this clearly on Friday.
SH16 NORTHWESTERN MWY – DELAYS – 12:45PM
Due to the truck crash on the Harbour Bridge traffic diverted from SH1 is now producing very heavy flows on SH16 (Northwestern Mwy). Please DELAY YOUR TRAVEL or expect delays this afternoon. ^TP pic.twitter.com/fzGu5rUdqn
— Waka Kotahi NZTA Auckland & Northland (@WakaKotahiAkNth) September 18, 2020
Any new crossing will result in one of two things.
- An overall increase the capacity for crossing the harbour. This will encourage even more people to drive (induced demand) which means that like with the Western Ring Route, any new road crossing isn’t going to have enough capacity to cope with the sudden influx of additional vehicles. In other words the same thing that happened on Friday with chaos on nearby roads would be repeated. More capacity across the harbour is also likely to undermine our other goals as a city as it means an even larger firehose of traffic is pointed at the city centre, right as we’re trying to reduce the number of cars there.
It’s also worth noting, what often gets overlooked is that this would mean more vehicles on the motorway north and south of where the crossings join/split and also on all of the local roads where adding capacity is even harder. If you use Onewa Rd or Esmonde Rd or any of other roads that interact or are near the motorway, they’ll be even busier.
- No increase in capacity. It’s also been suggested that in the event of a new crossing being built, the existing bridge could have space on it repurposed, such as for bus lanes and maybe even bike/pedestrian lanes etc. This would mean there is no real new capacity across the harbour and that the level of demand stays about the same. But that also means we’re still having to accommodate that traffic in fewer lanes than we do now.
In both of these situations we also need to remember that an issue could occur on that new crossing.
Of note, Waka Kotahi Senior Journey Manager Neil Walker says:
The network is one that doesn’t handle events like this well, Walker said.
“You can’t build your way of it forever and we’re going to have to think smarter about how we try and manage demand on the roads, so that’s greater use of the likes of public transport and that sort of thing, particularly around the peak times.”
‘You can’t build your way out of it forever’ – Neil Walker
Not designed to interconnect
It’s not just the issue of capacity that we need to consider, it’s also how the network is designed. The last public designs we saw for a new crossing are about a decade ago now but crucially they show that on the southern side, a new crossing would connect directly into the Central Motorway Junction without a connection to the city centre itself – effectively turning the existing bridge into a giant off-ramp. This explained well in this diagram below.
What this means is that in the event of issues on the bridge, traffic from the city wouldn’t be able to access the new crossing, except for perhaps via Grafton Gully but those streets would quickly overload. It also means that if there was an issue on the new crossing, traffic already on the motorways would have to exit and weave through the city to get between on/off ramps. The city isn’t designed to cope with that and will be less so in the future as we make it more pedestrian friendly as part of the City Centre Masterplan.
There are other forms of resiliency
The best way to add resiliency to crossing the harbour is to have a multiple separate networks, ones that is not affected by whatever happens on the others. Separate networks in the form of Skypath and a dedicated public transport crossing. While there is often little people can do in the immediate aftermath, if we had these already in place then over the coming days and weeks they would have allowed for people to change how they travel, blunting the impact of the lane closure. Note, the benefits of having separate networks applies not just to the harbour crossing but other aspects of our transport network too and is why light rail makes sense rather than putting all our eggs in the heavy rail basket.
One of the most significant examples of this was in San Francisco following the 1989 Loma Prieta earthquake. The earthquake damaged on of the sections of the Bay Bridge and it took about a month to get it fixed.
However, the Bay Area Rapid Transit (BART) tunnels, which cross under the bridge, were unaffected and able to be used the next day, providing the only direct connection between Oakland and San Francisco. Usage jumped dramatically – up 17% for the entire fiscal year and then grew from that in subsequent years. That showed that not only did it provide an immediate alternative but that many people permanently switched to using it.
Back in Auckland, the most recent papers we’ve seen on the topic of a harbour crossing showed that adding another road crossing would increase vehicle trips and make congestion worse, even if a combined road and public transport crossing was built. The best performing option was for a dedicated light rail crossing and road pricing on the existing bridge. As a bonus, it would also be cheaper.
This further highlights that we need to focus on adding the missing modes.