To me the new bus network presents Auckland Transport with many opportunities to improve transport in Auckland. These include:
- It simplifies the bus network and removes unnecessary duplication and inefficiency.
- It allows for greatly improved frequencies across much of the city.
- The simpler network structure means that it will be much easier to market the PT network as a whole rather than only being able to focus on individual parts.
- The network structure encourages AT to put effort into improving bus stops and interchanges around the network further improving its quality – an example is the proposed Otahuhu Interchange.
- The network provides a ready-made plan for what roads will need better bus priority built (e.g. bus lanes, bus priority at intersections etc.)
With this post I want to look at another opportunity that AT will hopefully make as part of the roll out of the new network – changes to bus stop spacing. The problem is that along many routes the spacing of bus stops is extremely close, sometimes less than 200m apart. I only checked a few routes but on them stops appear to only average about 300m apart. While that might be good for those living nearby meaning they don’t need to walk far to get a bus, it can make the bus slow by stopping frequently.
What kind of impact could changing the stop spacing have?
For the purposes of this exercise I’m going to assume that on average a bus loses about one minute of journey time per bus stop. That includes time to brake, dwell at the stop while passengers get on and off and then accelerate again. As a comparison, over a distance of 12 km (many bus routes will be longer than this) a bus that stops on average every 300m will make 40 stops, a bus stopping every 400m will stop 30 times and a bus stopping every 500m will stop just 24 times. Based on that one minute average stop time above then stopping every 400m could save 10 minutes per run while it could be 16 minutes saved with a 500m stop spacing. It’s also worth pointing out that in the situation above all stops are treated equal as in reality a larger stop where lots of people get on will likely be more efficient on a per passenger basis during the dwell time phase.
What are the benefits to increasing stop spacing?
The first one is that passengers get a faster trip whilst they are on the bus but that would have be partly offset by a longer walk to the bus stop. From an operations point of view, depending on the route that time saved might just be enough to allow an extra bus to be run without needing to buy another bus and hire more drivers. In effect it means that can either reduce how much we spend to get the same level of service or get more service (and therefore patronage) without having to spend more. Both options are positive.
The risk with increasing station spacing is that it the service becomes less attractive due to being harder to access stops. Bringing this back to the new network, the question is whether the increased frequencies on the new frequent bus network could be enough to offset the extra walking that would be required due to wider stop spacing. A research paper from Australia last year has attempted to answer exactly this question by surveying people in the major Australian cities. The abstract from the paper is below
Network planning of bus services requires addressing the trade off between frequency and coverage. Planning for good coverage of bus services using the rule of thumb that people will walk four hundred meters to access bus based public transport services means sharing the available budget between many services. For the same budget, the alternative approach of concentrating frequency on core corridors implies lower coverage and that some travellers would need to walk further to access bus based services. An understanding of to which extent people are willing to walk to a bus stop with higher frequency would provide empirical information for bus network planning.
The research question addressed by this paper is whether travellers are willing to walk further to a more frequent bus service in the context of Australian cities. A Stated Choice Experiment approach is used to elicit the trade off between walking further to access more frequent bus services. In doing so the paper investigates the potential success of reorientating a coverage approach to network planning, prevalent in many Australian cities to one predicated on concentrating frequency in corridors. The results show travellers in Australian capital cities are willing to walk around 206m to 327m further for a ten-minute reduction in bus headways. These research outcomes provide valuable Australian evidence confirming travellers are prepared to walk further to a more frequent bus service.
And just expanding on the conclusions they say
The major contribution of this paper is the quantification of the trade-off between walk distance and bus frequency as identified by the MRS. The results suggest that the travellers are willing to walk further to a more frequent bus service in all Australian capital cities. Travellers in Australian capital cities are prepared to walk further by between 206m and 327m for a ten-minute reduction in bus headways. The policy implications for network planning are that increasing frequency, even if it means travellers have to walk further to bus stops, will attract higher patronage. If budgets are fixed, this suggests that moving from a policy of coverage to the ‘European’ approach of concentrating frequency in corridors is likely to be a good policy if increasing public transport patronage is desired. Of course, concentrating frequency in corridors will require some travellers to walk further to access bus based public transport and will require policy-makers to consider and implement complementary policies to ensure accessibility is not reduced for those travellers unable to walk the additional distance. This could take the form of lower frequency access services or more flexible services to provide on-demand access to high frequency corridors.
In other words if we assume that we are at least a little bit similar to our cousins across the ditch then we are likely to see similar results too. It suggests that not only is the new bus network the right thing for Auckland Transport to be doing but that people will be prepared to walk further for higher frequency services without it compromising patronage (which would be boosted by the higher frequencies being provided). Implementing changes to bus stops spacing at the same time as the new network rolls out is something AT really should be doing.