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What influences public transport patronage?

One strange thing about NZTA is that, despite being a generally roads-obsessed organisation, there are parts of the agency which come up with great initiatives and great work. Whoever write NZTA submissions on plan changes and resource consent applications in the Auckland area often comes up with great points to make (often a lot better than what ARTA had to say), while another great part of the organisation is the work done to fund interesting research into transport matters. One of the more recent research reports put together for NZTA looks at the various factors that drive public transport patronage increases or decreases. Written by Judith Wang, of Booz & Company, the report’s objective was to undertake an in-depth analysis of factors influencing public transport patronage and to develop a model for future forecasting of patronage demands.

A brief summary of the results is included in the table below – which were derived from looking at patronage trends over the past 10 years in NZ’s three biggest cities, then comparing those trends to various factors that were taking place over that time: There are some interesting results here. The strongest factor (showing up as important in all situations except Wellington’s buses) seems to be that service changes have an impact on patronage: increase the service frequencies, or improve the quality of the service in other ways (such as making it faster) and patronage will boom.

The ‘elasticities’ of the relationship between these various factors and public transport patronage was also analysed. The higher the number means the stronger the connection – with positive numbers showing that the factor (as it increase) led to increased use of public transport, with negative numbers indicating that as that factor went up, public transport usage decreased: If we look at the bus data first for Auckland, the best way to improve public transport patronage in the longer term was to improve services, although higher fuel prices also had a reasonably significant effect on patronage. Interestingly, both fares changes and income changes didn’t have much impact on patronage. However, car ownership levels had a huge effect – it would seem that any level of increase in car ownership will have a massive negative effect on bus patronage. This would tend to suggest that bus patronage is focused around those who don’t own cars, and as soon as they acquire a car they don’t catch the bus anymore.

For rail, things are quite different. Service improvements in Auckland had a big effect on patronage – to a greater extent than for bus service improvements. Fares also had a bigger effect on patronage than with buses, perhaps suggesting that the decision to raise rail fares a week ago may have a bigger impact on patronage than I had thought. Interestingly, unlike buses there doesn’t seem to be a connection between car ownership and rail patronage. It would seem that people are happy to own a car while still catching the train to work in a way that they’re not content to still catch the bus once they have a car. Fuel price also seems to have less of an effect on rail patronage in Auckland than it did on bus patronage.

The study draws a number of interesting conclusions out of this data: I think the result I get out of all this is the difference in factors affecting bus and rail patronage in Auckland. While both respond to service improvements, as income rises and (most particularly) car ownership levels increase bus patronage falls away dramatically whereas rail patronage is retained. This would suggest to me that Auckland’s bus riders are more frequently catching the bus because they don’t have a choice – in particular they don’t own a car. By comparison, it would seem that train riders may be doing so by choice – because even when they purchase a car ridership levels remain relatively similar.

This is not particularly surprising and reflects the fact that we’ve generally ignored our bus system (Northern Busway excluded, which I think would probably exhibit similar characteristics to the rail network if looked at individually) over the past decade. Buses are slow, relatively expensive and generally inconvenient – so it would seem that many people in Auckland who use them do so because they have no choice. What we want to aim for is a situation where people are choosing to ride the bus – like they choose to ride the train – because it’s faster and more convenient than driving. The analysis above suggests that service improvements that achieve this will result in a significant boost to bus patronage.

2 comments to What influences public transport patronage?

  • tochigi

    rail services are (should be) genuine rapid transit. buses (with the probable exception of the Northern Busway, in the medium term) are not. people who can choose between private car or bus tend to choose car because there are not sufficient advantages in using the bus. it will generally take longer. the big advantage for buses in Auckland is the cost of CBD parking. but that is pretty much it. lack of late-night services and infrequent timetables are big demerits. on the other hand, trains can be much faster and the predictability of arrival time is a huge advantage. as BrisUrbane says, high frequency services 6am to midnight will attract a lot more users.

  • Kevyn

    I hope your comment “This would tend to suggest that bus patronage is focused around those who don’t own cars, and as soon as they acquire a car they don’t catch the bus anymore.” is incorrect otherwise there is no justification on NZTA subsidising bus services. Since this doesn’t show up for longer distance rail commuting maybe what is really being revealed is employment in non-cbd workplaces becoming increasingly inaccessibl in space or time by bus hence when people change jobs they have to buy a car so that th problem comes back to “don’t need to own a car” rather than simply “don’t own a car”.

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