Every day something goes wrong on our transport system somewhere. On our roads crashes and breakdowns are a daily occurrence while our rail network is not immune to faults and other issues creating delays. The impacts of these are often fairly localised but occasionally, if the incident occurs in just the wrong place and/or at the wrong time, it can become something much more serious.
Yesterday was one of those days and a large portion of the city was gridlocked after the harbour bridge was reduced to just a single lane citybound during the morning peak thanks to a crash.
A road-marking truck that flipped and burst into flames on Auckland Harbour Bridge has caused chaos across the motorway system this morning, with thousands of commuters left delayed by up to two hours.
The chaos has led to major congestion – now into the fifth hour – on the Northern Motorway and affected other motorways, particularly the Upper Harbour and Northwestern routes, as people tried to find alternative ways into the city.
Not even buses using the Northern Busway were immune as the crash occurred right after those buses have to merge with general traffic to cross the bridge.
This incident inevitably led some to suggest we wouldn’t have had this issue if we had another harbour crossing.
AUT University engineering Professor John Tookey said a second tunnel road crossing, as has already been mooted, would ensure Auckland would not be hit to the same extent as a result of a single incident.
“The fact of the matter is, if you have a tunnel somewhere else, then you’ve got traffic going through the tunnel ongoing uninterrupted during these incidents,” he said.
“The only way to manage this problem is to massively oversupply the capacity by having another motorway into the city, so you don’t have all your eggs in one basket when an accident occurs.”
I do agree with the suggestion of not having all our eggs in one basket but I’ll come back to that shortly. First though, it’s worth highlighting why an additional road crossing would not have helped.
The current thinking is for a road tunnel from somewhere around Akoranga all the way through to the Central Motorway Junction with the Harbour Bridge effectively becoming an off-ramp to access the city. As we’ve seen with every other roading project, over time it would encourage more people to drive. There are a number of issues with this but the one we’ll focus on is how it impacts this scenario.
As traffic backed up from the incident, it would quickly snake its way back along the motorway until it reached the point where the tunnel starts. At that point you end up with all the people who normally use the tunnel, and all those who normally use the bridge all trying to squeeze into the tunnel, creating new bottle neck, made worse as there will be a lot of people trying to get across lanes to access it.
We can be confident that this would happen just from looking at the impacts of the crash yesterday. As mentioned above, a lot of drivers tried to avoid the chaos by diverting along the Upper Harbour motorway in an attempt to get around the bridge. Only that motorway was simply unable to handle the volumes, especially after it joined SH16 causing it jam up too. I happened to be riding to work through the area at around 8am and due to the motorway being congested, drivers then also flooded onto local streets like Hobsonville Rd in an attempt to bypass the motorway congestion, jamming up those roads too. Through Upper Harbour and on the North Shore I noticed congestion in places I never have before – being on my bike I was probably one of the fastest things on the road.
There is also the issue that because the tunnel bypasses the city, drivers would then need to find a way back again.
Of course, there’s no guarantee that with a tunnel in place that a crash wouldn’t happen by the entrance to the tunnel resulting in exactly the same outcome as we had today (but with more cars to deal with).
As for Tookey’s comments that we need to “massively oversupply the capacity by having another motorway into the city“. Is he suggesting we need a spare motorway sitting about just in case something goes wrong? Not to mention the huge cost needed to achieve that with road tunnels looking to be in the $8-10 billion range. It’s also worth remembering this post from earlier this year where the NZTA confirm that building a new road crossing has the worst outcome on traffic volumes and speeds.
What that report also confirms as the best option, to build a light rail only crossing, happens to fit in with the need not to have all our eggs in one basket. That’s because while light rail would not have lessened the congestion that followed the accident, it would have meant that that fewer people were suck in it. Providing a dedicated PT crossing and upgrading the busway to light rail would encourage more people to use public transport and so that would help too.
Finally, as mentioned at the start, it’s not just the existing roads that have resilience issues, our rail network does too – for example, remember when a train derailed inside Britomart crippling the entire network for days. It’s a good example of why our next rail network should be different from our current one.