Many of the debates over the City Rail Link’s cost-effectiveness have revolved around the question of rail capacity. At what point does the railway network, without the CRL, become overloaded? How many people will be discouraged from taking the train because of this overcrowding? If they go back to driving, what congestion would they create? If they go back to catching the bus, what congestion does that create? All these sorts of questions are at the core of how, in particular, the Ministry of Transport undertook its review of the project’s cost-benefit analysis.
That’s how you end up with complicated tables like this:
In case you’re wondering why there’s nothing for the eastern line, it’s because the Ministry of Transport’s analysis showed that even without the City Rail Link, there was enough capacity in the rail network for Eastern Line trains right through until 2041. Yes, seriously.
A lot of the detailed analysis of the City Rail Link’s cost-benefit ratio confuses me, because – as I explained in this recent post – all the analyses make one big assumption: that car and bus capacity is unconstrained. What that means is that the modelling used to estimate the number of people catching the bus, train or driving into the city centre in future years does not have, as a part of its workings, anything which says “at a certain point the roads will be full of buses and cars and you can’t fit anymore in.”
What this means is that all the business case assessments of the project so far assume that the number of bus passengers in particular, will increase dramatically in the future – both in the “2041 with the CRL” and “2041 without the CRL” scenarios:
You get some idea what this might mean on the ground through the maps in this report, prepared by NZTA to inform the Waitemata Harbour Crossing Project. Firstly, looking at the number of buses we have not along key routes in the AM peak: The colour of the arrows are explained further in the table below: What this suggests is that above 80 buses an hour you start to get issues, and over 100 buses an our things really start to get problematic – requiring multiple lane busway operations that simply aren’t feasible in Auckland’s city centre.
Keeping this is mind, if we look at the “2041 no City Rail Link” scenario, we can see that the number of buses that would flood the city centre is completely infeasible: If running over 100 buses an hour along arterial roads is problematic, then running two or three times that number along Symonds Street, Albert Street (both ways) and Fanshawe Street is, quite frankly, impossible. As someone I was talking to earlier this week said, as this point you’d need people sitting on the roof of the bus for such a scenario to make sense. So the map above makes a good argument for the necessity of the City Rail Link (and possibly also a North Shore Line).
However, it’s the next map which is perhaps even more interesting – the number of buses in the “2041 with City Rail Link” scenario: While buses coming in from Grafton Bridge have reduced down to a more feasible level, we still have a completely impractical number of services coming in from Upper Symonds Street, we will have a huge number of services both ways along Albert Street and, obviously, we’ve done nothing about the North Shore issue.
The impossibility of running so many buses along Albert and Symonds Street, even in the “with CRL” scenario, means that these passengers would have to travel by some other means. Travelling by car is pretty infeasible, as we will have dedicated so much roadspace in the CBD to bus lanes to handle the North Shore buses, as well as whatever we find to be the actual maximum number of buses from the south and west the city’s streets can handle. Also, if we’ve started giving effect to the City Centre Master Plan, much more of our city’s roadspace will be dedicated to pedestrians. The train is the only feasible alternative.
This potentially has a huge effect on assessing the cost-effectiveness of the City Rail Link. Let’s analyse what the capacity of the city centre for buses and cars might actually be:
- In 2010 there were around 34,000 car (including drivers and passengers) trips into the CBD at peak times. If we think about the City Centre Master Plan reducing roadspace throughout many parts of the city centre (like Quay Street, Queen Street, Hobson/Nelson streets and Victoria Street), as well as having to give up roadspace to bus lanes to accommodate the significant increase in bus numbers, I think a future car capacity of the CBD is unlikely to be much more than 30,000.
- In 2010 there were 23,000 bus passenger trips into the CBD at peak times. Most of these end up along Fanshawe, Albert and Symonds Street, which are all getting reasonably close to that 100 buses per hour capacity limit where things start to not work particularly well. Improved bus routes within the CBD (such as taking all North Shore buses off Albert Street and sending them via Wellesley Street instead) should allow for a fairly significant increase to this number, but certainly not more than half as many buses again. So let’s say a capacity of 35,000 trips at peak times.
If we set these car and bus capacity constraints, we see a huge impact on the number of rail trips. The three assessments done disagree on the total number of trips into the CBD at peak times in 2041 (excluding walking and cycling), but we can take an average of the three to come up with just under 105,000. Assuming ferry patronage increases from 3,000 to say 5,000 – you start to see that the rail system will have to take a pretty massive number of trips.
In the “2041 with CRL” scenarios, none of the assessments done suggest that rail will have this many trips – simply because they haven’t recognised the capacity constraints on the city centre’s road network. Therefore, all the assessments have under-estimated the impact of the project, they have significantly under-estimated rail patronage and therefore it is likely that they have all under-calculated the project’s real cost-benefit ratio.