Three types of bus route diagrammed (or; why our public transport is inefficient and overpriced, yet overcrowded and underfunded)

When we talk about public transport investment, we often have the idea that “more is better”; more money needs to be invested, more capacity will result in more ridership, and more ridership will relieve traffic congestion. Politicians, particularly, like to boil their transport proposals down to a dollar value. However, this approach to discussion doesn’t capture anything of how public transport works: it doesn’t explain why a few of the world’s transport networks (Hong Kong, Singapore, the London Underground) operate in or near profit, when ours needs heavy subsidisation, nor does it allow us to judge the merits of different transport proposals beyond “this one costs more, so it must be more”.

In the hope of encouraging a richer discussion, I’d like to offer a brief taxonomy of three different types of public transport routes, with an explanation of how they function in the context of our city.

The commuter service will be very familiar to most public transport users – in Brisbane, this is the model for our entire train network, and almost all our bus routes.

A commuter service in the morning peak collects passengers from a suburban area, drives into the city (either on dedicated infrastructure or competing with peak-hour traffic), and delivers them to the central business district. Most vehicles will then run empty (“deadhead”, “reposition” or “run blank”) back to the suburbs to begin another service, as morning demand is heavily biased towards inbound services. In the afternoon, the services run the other way, distributing city commuters back to their suburban homes.

This is the most common form of public transport, and the one we often think of as the most important. But it’s also by far the least efficient – when everyone rides from one end of the line to the other, a fully-loaded bus can only carry its full capacity (in the example diagram, 50 passengers) once in a trip. The temporally short and one-directional peak demand also means a lot of empty running between services, and vehicles being idle or underutilised for much of the day.

A shuttle service connects multiple points of interest (or activity centres) together. These services can be loops or linear, but the key difference from the commuter service is that demand is more spread out, in both space and time. They are vastly more efficient than commuter services – the shuttle in the example diagram carries twice as many passengers, in half the time, as the commuter service; can simply turn around at the end of the line instead of running empty, as the demand is bidirectional; and can run at fuller loads for more of the day, as passengers are travelling to a greater variety of destinations for a greater variety of reasons. In cities with profitable public transport, most of their services fit this model.

The most notable shuttle service in Brisbane is the 66, the city’s busiest bus route, which runs on a dedicated busway and connects the Brisbane CBD to the main railway station, the Cultural Centre, three hospital precincts and two university campuses. Most of Brisbane’s busway services and other high-patronage routes, particularly the 199, 196 and 60, which all run through the City from approximately West End to New Farm, could be considered shuttle services too.

Local services loop from one major activity centre, usually a shopping centre or railway station, around a suburb via multiple minor activity centres, such as smaller shops, schools and housing estates. They are arguably the most important type of public transport route, as they expand local mobility, reducing households’ dependency on cars and empowering those who can’t or don’t drive. They’re also often the most overlooked and undervalued services on a network, because:

  • If passengers are using the bus to go only a few stops (to access a local shop, for example), low average loading may give the impression of low demand. In the example diagram, the bus only ever has 10 to 20 passengers on board, despite carrying more passengers in total (70) than the commuter service (50). This encourages network planners to decrease frequency of these services in the name of efficiency, making them less useful and less attractive to potential riders.
  • There’s a cultural tendency to view these services as “shopper hoppers” – a convenience for retirees, the unemployed and other idle people who have nothing better to do. Therefore, they are only run in off-peak times, when vehicles can be spared from more “important” commuter duties. This, in turn, limits the usefulness of the local service: no-one can use it to get to work or school if it only runs in the middle of the day.
  • Simply: politicians, public servants and planners tend to be CBD commuters, and are only used to thinking of public transport in those terms.

Do these ideas affect how you think about our public transport, and how we should reform and develop it in the future? For me, thinking about these different types of service has made me less keen on Cross River Rail (which increases capacity for commuter trains to the outer suburbs), and more keen on the Brisbane Metro (which increases capacity for shuttle-style busway services). It’s also made me think that perhaps expanding and extending local bus services, so people can do more within their local community, might be a more effective use of resources than putting more inefficient commuter services into peak-hour traffic.

Ultimately, public transport reform can’t happen in isolation. The efficiency benefits of shuttles over commuter services are immense, but effective shuttle services need more decentralised activity centres to operate between. Similarly, improved local bus services are a fantastic complement to walkable, mixed-use communities in our suburbs, but without other reforms they risk becoming “feeders”, merely connecting houses to railway stations as part of a commuter service which is no more efficient for being split over multiple vehicles. The cliche that land use and transportation planning are two sides of the same coin applies as much to public (and active) transport as it does to roads and highways.