Regular readers will be well aware that we strongly believe our transport agencies need to rethink the Additional Waitemata Harbour Crossing. It appears to us that the price tag of $4-$6 billion is way out of proportion to the benefits another road crossing would provide. This view only strengthens the more we see the changes that are occurring, for example just last week we learned that the NZTA’s own post implementation reviews highlighted that traffic volumes weren’t living up to projections on a number of motorway projects. We also found out that one again that vehicle kilometres travelled in Auckland had fallen in both real and per capita measures despite strong population growth.
In Patrick’s letter to the NZTA he said:
It is our view that both a driverless Light Metro system, or a continuation of AT’s proposed Light Rail network across the Harbour, to Takapuna and up the Busway, need to be properly explored as the next possible crossing over the harbour. As they are likely to achieve all of the aims NZTA and AT are charged with delivering for the city much more completely and at a lower cost than any additional traffic lanes and without any of the disbenefits.
– the economic benefits of true spatially efficient urban transport system linking the Shore to city and the isthmus RTN
– make a massive transformational shift to public transport
– real carbon and other pollution reductions of scale from a 100% electric system
– huge place benefits, including a real reduction in city car and bus numbers
– no additional massive costs on approach roads
– resilience of additional systems as well as route
With this post I want to look at the idea of extending AT’s proposed light rail (LRT) across the harbour. So far we know that AT are looking at very high capacity LRT vehicles – up to 66m long and capable of holding around 450 people.
They would run on at four LRT routes on the isthmus on Sandringham Rd, Dominion Rd, Mt Eden Rd and Manukau Rd, combining into two corridors through the CBD – Queen St and Symonds St – before terminating at Wynyard. These are shown below.
So what if we didn’t terminate them in Wynyard and instead extended them via a new crossing to the North Shore. As we know one of the features of LRT is that it can run at street level allowing for the network to reach past the expensive grade separated infrastructure like we see on the busway. Of course that can also be a curse if it is run mixed in with general traffic. Outside of the busway a good compromise is like what appears to be proposed for the isthmus with dedicated lanes and signal priority.
We know that the busiest bus routes on the North Shore are the Northern Busway, to Takapuna and up Onewa Rd. Those areas/routes also happen to be where some of the highest levels of development is allowed for on the North Shore as part of the proposed Unitary Plan – although I think a lot more should be allowed.
Combining the routes for the Isthmus with those corridors on the shore could deliver us something like the network below. You can see it features one route to Takapuna, one to Glenfield and two routes combine to serve the Northern Busway – one of which goes via the Universities, the Hospital and Newmarket
The immediate question many of you might have is about capacity and whether LRT would have enough to serve the shore. Assuming a frequency on each route of roughly one service every 5 minutes that would combine for a capacity across the harbour of over 21,000 people per hour. To put that in perspective, currently over the two hour morning peak around 9,000 people cross the harbour bridge on buses. As such LRT would allow for more than a fourfold increase compared to what we have now and assuming they could do around 80km/h – which is the speed of the busway and seems fairly common on many overseas LRT systems – it would remain time competitive with driving at most times.
The biggest issue with any proposal will always be the cost however this is where LRT could prove a winner. In the last harbour crossing study a rail only tunnel was estimated at ~$1.6 billion – far cheaper than a road crossing. Add in converting the busway and the routes to Takapuna and Glenfield and I suspect we’d be looking at $3-3.5 billion. It’s worth noting that a high level study in 2012 estimated a similar network – but with the Takapuna branch extending all the way up East Coast Rd and to Browns Bay at around $4.5 billion.
Of all of it, it seems that the biggest challenge would end up being the section on the city side from the crossing to where the Queen St and Symonds St routes separate as that would have a high frequency of LRT vehicles through an area with a lot of intersections and conflicting movements. In saying that I’m sure it’s something our talented engineers are capable of solving.
Overall the thing I like the most about the idea is that it allows for through routed connections, removing any need for large terminals from the CBD/Wynyard which is what we would have with the current LRT proposal and/or if we decided to do a light metro or heavy rail option. Compared to other options that have been presented in the past it is also the only one that also looks at serving the western North Shore. Both the western and eastern routes could also be extended if needed. The biggest downside compared to the other rail based options is that LRT would still need a driver which would have an impact on the operational costs.
Lastly it’s worth noting that I’m fully aware that this may not be the best solution. A different solution might turn out to be better however the point of the post is to highlight that options other than the default of a new motorway tunnel exist. We want to see the NZTA and others assess any future crossing from a fresh perspective – much like what happened with the City Centre Future Access Study.