Through-routing buses: an update

Last week I put together a proposal to revolutionise Auckland’s bus system by focusing on through-routing the buses. Basically, this involves linking up bus route that come from either side of the city with each other – so that it’s possible to have buses actually travel through the downtown area. This makes public transport far more useful for someone who lives on one side of the city yet works on the other, but still means that the bus route can service the CBD.

There was some interesting feedback on the proposal, with people pointing out potential problems relating to unbalanced service frequencies and overly long routes. While there are definitely some merit in those arguments against through-routing some particular services, I still think that the advantages significantly outweigh the disadvantages.

Humantransit has put together a post on the issue as well, which makes for interesting reading. Particularly the reasons for through-routing, and the reasons why it perhaps isn’t as common as one would expect. Let’s start with the reasons to do it:

Fewer “transfers.” Some people are actually going from Connecticut to New Jersey, for example, and through-routing lets them make this trip without changing trains. More commonly, a lot of people from the north (i.e. Connecticut) are going to southern parts of New York City, while a lot of other people from New Jersey are going to northern parts of the city, and a through-routed system serves both groups, which are briefly on the train at the same time in the city. Because of the decentralised structure of Paris, lots of Parisians are riding across the city to the far side, in both directions, so the RER’s through-routed structure is absolutely essential to avoid forcing huge masses of people to change trains.

I think this reason is particularly important for Auckland. Only 11% of the region’s jobs are located in the CBD so therefore people need to travel to areas other than downtown for work. At the moment that would involve at least one transfer, which makes the trip a lot longer and potentially more difficult (especially if one needs to walk between services for any particular distance).

Reduced need for terminus facilities on expensive downtown real estate, and thus potential for higher frequency. Ending a line downtown means having facilities to store a bus or train for at least a few minutes, consuming expensive space. Trains typically reverse direction at an end-of-line station, so the driver needs to close her cab, walk the length of the train, and get herself set up on the other cab; she may also be entitled to some break time. A train occupies one of a limited number of tail tracks while this is happening, so this function becomes THE limiting factor on the frequency of the whole line. Downtown, there are lots of physical and cost constraints on station design, so you almost never have as many tail tracks as you’d like. Buses need space to turn around and their drivers, too, are entitled to some break time at the end of a trip, so end-of-line stations on frequent services need space for a number of buses to pile up in a first-in-first-out queueing arrangement. All this takes a lot of space, and this space is a lot cheaper at the end of a suburban line than it is in the middle of downtown.

This is a good argument for the CBD Rail tunnel in many ways, but the same could be applied to bus services. We have ruined lower Queen Street by turning it into a massive bus terminal. Perhaps if services were through-routed we wouldn’t need to dedicate such a large area to buses and could reclaim some of this area?

Fewer line ends, for reduced operating and capital cost. The time it takes to turn around a bus or train around, and provide the driver break, is usually not related to the length of the line. Through-routing two routes eliminates two ends-of-lines, which reduces the cost, both operating and capital, of those inefficient turnaround movements. Often, through-routing two lines actually reduces, by one or two, the number of buses or trainsets required.

I think the advantage here would be mostly related to more passengers using the “reverse-commute” part of the trip. Currently most buses that travel in reverse-peak direction are pretty damn empty, or (even worse) are not in service. Those not in service trips cost money to run, and it they could be even half-full with passengers continuing on their journey then the efficiency of the system would be enhanced significantly.

Fewer vehicles downtown providing the same service. Sometimes, too, the pre-through-routed lines overlap in downtown, so the through-routing eliminates that overlap. Instead of having a bus dropping off passengers interacting with another bus picking passengers up, you have one bus dropping off passengers and picking them up at the same time. For buses especially, downtown street capacity is a very limited resource in big cities, and through-routing helps economise on it.

This could also be a big advantage. You could potentially provide a similar, or greater, level of service with fewer vehicles. That has to be a good reason to look at something like through-routing.

And now for the disadvantages, or more appropriately – the reasons why it’s not more common:

Unbalanced markets on the two sides of downtown. There’s never an exact one-to-one match between routes approaching from one direction and those approaching from the opposite direction. For example, San Francisco’s downtown is on the bay at the northeast corner of the city, so there are no routes extending north and east that could be paired to routes flowing south and west. To the extent that such through-routes have been created (e.g. San Francisco’s Muni Metro T line) the result is a circuitous approach to downtown for one of those lines.

This is potentially problematic, although I think the North-South route that would be the most usefully through-routed could balance quite nicely. My original proposal was to match up buses from the west with buses from the isthmus – although I think it might be more beneficial to link up West Auckland buses with those running along Remuera Road  and/or Tamaki Drive. That would match up service levels better, and offer a more useful east-west link. So there’s a bit of work to be done there, but I certainly think that with a bit of analysis one could easily find some routes that have similar levels of provision and link them up.

Excessive line length. The probability that your train or bus is delayed is directly related to how long it’s been running since it last had an end-of-line break. (When a vehicle arrives late at the end-of-line, its break time is reduced, so that it can leave on time or at least not as late.) Through-routing makes lines longer, so it can compound this problem. This is obviously more of an issue in services that are exposed to more causes of delay, such as services in mixed-traffic and services with driver-administered fare collection.

Again, yes this could be a problem if you’re running a bus from Papakura to Albany it might take close to two hours at peak time. Perhaps it would make sense to exclude the long-haul service from through-routing?

Jurisdictional barriers. Finally, there are plenty of cases where through-routing would be in order but the two sides of downtown are different jurisdictional turf. They may be different states, as in New York, or different transit agencies. In the UK and Australia, they may be different private operating companies — and although both are government-subsidized, UK/Australia governments tend to defer to private companies about network design, so you often get designs that reflect company turf boundaries rather than efficient use of subsidies or meeting the needs of the customer. (London is an exception, and some Australian states are also working on this problem.)

As ARTA are the overseers of the whole network, this shouldn’t be a problem. However, in practical terms it seems that the private operators have been left to develop their “patches”, which could make through-routing difficult. However, the extra power given to ARTA by the Public Transport Management Act, plus the implementation of integrated ticketing could solve this problem.

Infrastrucutre barriers. Your great-grandparents’ jurisdictional barrier is often your infrastructure barrier, and New York City is the obvious example. Because each commuter rail line was designed by a separate entity, and each of these entities was thinking only about getting people into Manhattan, the terminal stations are not physically connected in the way you’d need in order for trains to flow through. This is the cause of most of the capital expense in Alon Levy’s proposal for New York above.

I don’t think this is necessarily a problem in Auckland. For my proposal to work you’d need bus lanes on Albert, Symonds and Queen Streets – plus smaller areas of bus lanes along parts of Karangahape Road. Queen Street is the main area of those without bus lanes, and they are desperately needed. For rail, the CBD rail tunnel would be necessary – but then again it’s a critical project for so many reasons!

They just haven’t thought of it. If your transit agency has non-through-routed lines, and you can’t figure out why, send them a link to this post, and ask them!

Perhaps this is the real reason. So come on ARTA – prod prod, think about it!

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