Last year the Wellington’s semi-equivalent of our Auckland Transport Alignment Project was released for consultation. The work, known as “Let’s Get Welly Moving”, was done as a result of the declined consent for the Basin Reserve Flyover which required Central and Local Government to go back to the drawing board.
As Matt pointed out here in his post on the work, the recommendations were incredibly disappointing, basically using the pretence of improving public transport, walking and cycling to push through some massive roading investments. I’m not going to go into further detail on that part of it, as what I want to touch upon in this post are some issues with the work the report did into Mass Transit options.
Underestimated Light Rail Capacity
The first issue that I had with the Wellington Mass Transit Summary Report was that that is was working on the assumption of 34 metre long Light Rail Vehicles, each carrying 250 people. This is on the low-end side of modern vehicles, which generally are up to 45 metres long, or can be coupled together, as is proposed for Auckland. Longer vehicles mean much higher capacity, with each vehicle able to carry close to 500 people.
This under-estimating of light-rail’s capacity has some important implications, because many of the overall work’s findings repeatedly are subtly disparaging to light-rail, basically saying that it’s just an expensive way of doing something that buses can do just as well. We know from detailed studies in Auckland that this isn’t true, but under-estimating light-rail’s capacity means the comparison between it and Bus Rapid Transit is not made fairly.
Bus Rapid Transit vs Demand
Many of the findings rely upon 2031 modelling, which suggests that the largest vehicles would be needed for Bus Rapid Transit with 24m vehicles running every two minutes to serve the demand for about 4500 southbound from Wellington station during the morning peak. Assuming that Wellington’s transport models are fairly similar to Auckland’s, this finding concerns me as we are very familiar with many of the shortcomings of these models. In particular, they:
- Consistently underestimate PT demand
- Particularly underestimate people’s willingness to transfer between public transport services
Correctly estimating the willingness to transfer is particularly important for this proposal, as people transferring between the rail terminus at Wellington station and the Mass Transit line will make up a huge proportion of the corridor’s demand.
Of course, Wellington could look at a second Bus Rapid Transit corridor or accept low future PT level of service with degraded placemaking due to wall to wall buses. However, this is where Light Rail could do well as it gives more wiggle room if growth is higher than expected as you have space to increase frequency as well as procure extra vehicles to combine creating much larger capacity than Bus Rapid Transit while still maintaining place.
The Route Plan
The route planning of the Mass Transit corridor especially the southern end of very odd for a few reasons.
The first reason is the assumption that Mass Transit needs to work around the motorway tunnels assumed as a given rather than be planned in own right leading to a similar issue to AWHC in Auckland where tying the rail/road together doesn’t make sense.
The reason it doesn’t make sense to tie them together is a new tunnel for Light Rail next to the existing tunnel does not make sense from a PT operations perspective for two reasons:
- Hataitai is pretty low density on the route on one side, and on the other side, your catchment is a park;
- It divides unnecessarily your spine into two branches meaning you need double the vehicles to maintain frequency or you spilt the frequency between Newtown and Kilbirnie.
A better solution is to create a route that can serve both Newtown as well as Kilbirnie on a single spine creating a more frequent linear network. Two options exist that could solve this issue well:
- Option S2 which after Newtown continued to Kilbirnie via Constable and Crawford St;
- Option S4 which after Newtown continues to Wellington Zoo then to Kilbirnie via a new tunnel to Coutts St;
Part two of the document contains all the potential route alignments if interested.
No real reason was given why option S2 (which would be much cheaper due to no tunnel) was dropped other than to say it was close to residential properties and the street was a little narrow in places. However, many parts of the route in Wellington will need to deal with this problem. Grade might be the problem further investigation should take place.
S4 was dropped due to cost and the tunnel portal effects on residents, but if we are going to be making this large step change investment then value engineering doesn’t make a lot of sense.
Other than the benefit of better frequencies, the service becomes simpler for users as you can hop on any service, has lower operating costs to achieve same capacity while also allowing branching the route in much more useful places. The report makes it clear the endpoint would eventually be the Airport, but if the branching is done in the right place then we could also extend the service via a new branch for example to Miramar as the spare capacity would exist.
The report worked on the assumption of a 34m LRV running every 4 minutes looking at the difference between an S3 and S2/4 if we also wanted a branch to Miramar:
Get Wellington Moving S3
- Wellington to Newtown – Every 8 min
- Wellington to Airport via Kilbirnie – Every 16 min
- Wellington to Miramar via Kilbirnie – Every 16 min
- Wellington to Newtown/Kilbirnie – Every 4 min
- Wellington to Airport – Every 8 min
- Wellington to Miramar – Every 8 min
Future Proofing for Light Rail is not Easy
One of the more interesting reports on the Let’s get Wellington Moving website is an Opus BRT Investigations Summary, which is different from the previously linked Mass Transit Reports. The report notes while future-proofing Bus Rapid Transit for Light Rail is possible, there are some huge trade-offs and issues:
Cost – if all LRT-ready elements are incorporated into the BRT scheme, then the cost difference between this level of implementation and a LRT scheme reduces, suggesting that it might be better to install LRT in the first place. A better approach is to design in some LRT-ready elements (predominantly alignment related) that do not preclude a conversion in the future for a lower expenditure. However, this approach may lead to the situation in the future, where it is more difficult to justify the upgrade on a cost-benefit aspect, as the ridership (and other) benefits may be much lower for the conversion.
Construction Impact – a second lengthy construction programme on the same corridor is likely to be undesirable unless a good alternative route was identified (which would be difficult in the Wellington context).
For the above reasons, the optimum approach in Wellington is likely to be that taken by most other cities – to build in some lower level of LRT-readiness to the BRT system (based on protecting the alignment and providing some BRT benefit at the same time), but with the expectation that this is unlikely to occur in any reasonable planning timeframe
Also from the report:
- BRT can be successfully converted to LRT in the future;
- Minimal LRT ready elements should be incorporated into the BRT corridor to minimise costs;
- If LRT will definitely be implemented in the future, then it is more cost efficient to build it now;
- BRT can drive significant mode share shift from private car, but it requires the system to be designed, implemented and operated to a high standard (i.e. to a similar level to that considered “normal” for a LRT system; and
- Constructing LRT on the existing PT corridor either now or in the future could have significant effects on both PT usage and other modes due to the additional infrastructure requirements and need to relocate all services / utilities from the proposed route.
The Mass Transit Report also noted:
Evidence from other cities (Brisbane, Sydney) indicates there are likely to be significant challenges associated with the future conversion of BRT to LRT. The challenges are associated with the provision of alternative routes for public transport and other motor vehicles during the deconstruction/reconstruction process, as well as the need to replace most of the costly infrastructure.
The City of Ottawa has recently begun implementing the conversion of their highly successful BRT system to light rail, which is expected to open in 2018. The high growth rate of the city, and very high patronage demand on the BRT were the key drivers for this change. However, it has been found to be an expensive undertaking.
- To future-proof for Light Rail properly often means the difference between BRT to a quality standard and LRT costs is low, so a minimal amount of future proofing is recommended i.e. just enough not to preclude it completely;
- Be very wary of talk of future proofing Bus Rapid Transit corridors for Light Rail;
- Upgrading from BRT to LRT is harder than expected, due to having to close the corridor during reconstruction;
- If you know you will need Light Rail in the future build it straight off, or deliver low cost/disruption bus upgrades in the interim rather than full BRT;
This is all not to say that the best option for Wellington is not Bus Rapid Transit rather than Light Rail, but I do think there were a few key issues that were a little off. You can find all the detailed reports here. There is a whole bunch of detailed reports on issues other than Mass Transit towards the bottom of the page.