Cars, trucks and buses: the realities of private commutes

The first exhibit shows the share of journey-to-work trips by mode in Australia’s capital cities. The data is from a paper by Paul Mees and Lucy Groenhart, Transport policy at the crossroads, published in December 2012.

The analysis by Mccrindle Research I cited last time showed only 10% of Australian commuters use public transport. However Mccrindle’s work covered the entire nation; the Mees and Groenhart analysis is just for capital cities (excluding Darwin).

Their work shows the mode share of public transport for work trips, aggregated across the capitals, is a much healthier 16.8% (1).

In fact the share of commutes made by public transport, walking and cycling increased over the last 15 years. Back in 1996 15% of trips to work were made by public transport; by 2011 the share had increased to 17% (2).

Conversely, the share of work trips by car declined steadily over the last fifteen years. Cars accounted for 78% of journeys to work in 1996 but only 75% in 2011.

Since they’re moving in opposite directions, it’s tempting to assume that commuters are swapping their petrol guzzlers for trains, trams and buses. While that happens to some extent, the numbers don’t suggest it’s the primary explanation for the change in the pattern of mode shares.

Notwithstanding that cars lost share over 1996-2011, the second exhibit shows that the absolute number of car commutes in the capitals increased substantially over the same period, growing by 1,039,009 trips.

This is 2.2 times larger than the combined increase in public transport work trips (354,419), walking work trips (75,235) and bicycle work trips (36,181) over the same 15 years. The latter three are growing decidedly faster than driving, but from a much smaller base.

Driving isn’t losing popularity as a means of getting to work. For example, the number of car-based commutes grew by 12.8% over the most recent five year inter-census period (2006-11). That’s well short of the growth in public transport over the same period (26.8%) but considerably higher than the 8.3% growth in population.

In fact it was the highest inter-census increase for cars for the entire 1976-2011 period examined by Mees and Groenhart. Indeed, the number of car commutes increased on average by 9.8% between each Census over 1996-2011, compared to an average of 7.3% for each Census period over 1976-1996.

The gap between the mode shares of cars and public transport is closing very slowly. Even in the (admittedly unrealistic) event all modes were to sustain into the future the growth rates they experienced between 1996 and 2011, it would take until around the turn of the next century for public transport to get to even a 33% mode share.

What these numbers suggest to my mind is that it’s not enough for policy-makers to focus primarily on public transport and land-use changes in the planning of our cities. Effective policy can’t be confined to opposing occasional new freeways and supporting occasional new rail lines.

Most of what’s needed doesn’t involve new infrastructure; we’ve already got a lot of that (see Is more transport infrastructure all our cities need?). The problem is city managers aren’t managing it effectively. They’re not pricing and regulating it properly because it’s politically harder to do that than promise big-ticket items.

Of course there’s a need for incremental improvements to support public transport, walking and cycling; but it’s not enough. It’s a virtual certainty road-based transport will remain the dominant mode for many decades to come. Action is needed to reduce the negative impacts of cars on urban amenity, personal safety, and sustainability while optimising  their benefits e.g. by managing congestion better through road pricing.

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1. It’s important to appreciate that the journey-to-work is a minor mode; it only accounts for around a fifth of all trips. However it’s important because work trips are longest; they’re the least discretionary trip; they’re the purpose where public transport does best; and, because they’re subject to peaking, they determine the maximum capacity of transport infrastructure.
2. Over 1996-2011, walking’s mode share increased from 3.5% to 3.8%; cycling’s from 0.9% to 1.3%; and trips in the Other purpose, which includes motorcycles, taxis and trucks, from 3.1% to 3.5%.