Why are we driving less?

Per capita distance driven in cars and light trucks, 1970-2007/08 (click to enlarge)

I’ve mentioned before how travellers in developed countries like the United States, Britain and Australia are driving less.

The accompanying chart, from a new paper, Are we reaching peak travel? By Adam Millard-Ball and Lee Schipper of Stanford University, shows the change in per capita distance driven over the period from 1970 to 2007/08 (before the GFC in September 2008) in eight developed countries, including Australia.

It can be seen that the rate of growth in per capita car travel has been slowing for some time in Australia and has actually declined in recent years. As we’ve gotten richer we’ve driven less.

What explains this phenomenon?  As with most things, it probably doesn’t come down to one dominant explanation. It’s more likely the coincidence of a number of factors (although some will be more important than others).

Higher petrol prices are one likely explanation because they started rising at a higher rate than the CPI about 10 years ago. However as I’ve discussed here, they didn’t rise any faster than average earnings over this period. Further, the flattening in car travel preceded the very large increase in the price of petrol from 2008.

Another likely explanation is increasing traffic congestion and greater restrictions on parking. Travellers may still drive for much the same time per day on average but lower speeds mean they can’t travel as far.  Higher parking charges discourage car use and encourage use of alternative modes, at least for those like CBD workers who don’t have much choice about where they work.

While the declining rate of freeway construction in many cities contributes to traffic congestion, the converse is that greater investment in public transport has made it a more attractive alternative to driving for some types of trip.

This would be the case in the CBD where public transport is most competitive against cars. The rapid (absolute) growth in jobs in many central cities over the last 15 years would have helped shift more commuters onto public transport. Growth in population in the inner city could also have contributed somewhat to this phenomenon.

Vastly cheaper air travel has virtually wiped out the long distance drive. Thanks to Tiger Airways and their kind, there is now a generation of students that haven’t experienced the dubious delights of driving the Hume Highway. An increasing proportion of people don’t drive as much for the simple reason they spend a couple of weeks each year out of the country, either holidaying or on business. Their place is taken by incoming tourists who have a higher propensity to use public transport.

Also implicated in the decline is a range of what can loosely be termed ‘demographic’ factors. Read the rest of this entry »