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.

The leading edge of the baby boomer bulge is now hitting retirement age. This represents a significant decline in the demand for driving since people tend to travel less as they get older. The growth in female workforce participation that drove the increase in driving since circa the 70s has also slowed appreciably.

As I’ve discussed before, Gen Y do not show as much interest in driving as earlier generations. It might be that cars, which were a potent ‘coming of age’ symbol for baby boomers, are viewed as more of a commodity by Gen Y. After all, if mum and dad are cool about you having lovers home for the night, that’s one less reason to have a car.

Technology has also contributed to the need for less travel and hence less driving. There’re activities like banking, videos and some shopping that can now be done entirely over the net. However the effect of technology is by no means clear cut – there’s a view that improvements in communications technology actually promotes more face-to-face contact and hence the need for more travel.

Other possible explanations are that increased environmental awareness discourages car use and greater consciousness of health promotes walking and cycling as an alternative to driving. My feeling is that these are very important to a very small segment of the population.

Perhaps the most important explanation – and certainly one of the more interesting ones – is the idea proposed by David Metz that car use has hit saturation level (gated, but more here). As David Metz explains it, we’ve got to the stage where we have a choice of (say) three supermarkets within 15 minutes travelling time. The law of diminishing returns suggests that we’re happy with that – we can’t be bothered travelling even further in order to have a choice of even more supermarkets.

Supermarkets are in a class he calls ‘replicable destinations’ and most of our travel is to these sorts of largely interchangeable places. However there are also ‘status destinations’ like football stadia, waterfront houses and ‘good’ schools.  They aren’t replicated as easily but high demand leads to higher prices and/or overcrowding and hence, he says, saturation of travel.

Only when we fully understand what underlies the fall in total kilometres of car travel can we be confident that the decline isn’t merely a blip on the long-term upward trajectory of demand for driving. The nature of the key forces – whether for example they are endogenous (e.g. congestion) or exogenous (e.g. demographic) – is also likely to have implications for how we manage the total transport task and matters such as the role of different modes.

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6 Comments on “Why are we driving less?”

  1. TomD says:

    The US figs could well be more closely related to higher ‘gas’ prices than that graph suggests.

    The problem arises from ‘averaging’ per capita GDP/earnings.

    As your graphs previously disclosed all the wealth of America has gone to a very small percentage of the population and earnings or wealth for the vast majority have either stagnated, risen only slightly or dropped dramatically.

    While in the meantime, although by word standards US petrol is still relatively cheap, the actual price has risen dramatically from around $1 per gallon not too many years back to almost $4 now.

  2. Bruce Dickson says:

    Am very interested in the implications of reduced tendencies to drive by car for tourism.

    In Australia around 90% of domestic regional/non metro tourism has been undertaken by road and driving. Making it by far the most important means of access and of generating non-Metropolitan tourism revenues.

    Do you have any figs on the potential fall off in use of drive-based access to destinations .. other than between capital cities? It would be interesting to see if these matched any possibly related fluctuations in regional tourism revenues and visitation levels.

    A further consideration is that major airline and air services to many of these places are either not as strong, are non-existent or cost much more in ticket price per km travelled than that found between say a major route like Sydney to Melbourne.

    These factors might therefore possibly still function strongly as a counter force to reductions in any such car travel changes being experienced along the inter-capital city routes.

    Like I said, would be most interested to see if you have come across anything of value and credence concerning these possible flow on implications.

  3. jack horner says:

    The linked article says, ‘a saturation of the demand for daily travel is to be expected, a novel conclusion’

    If ‘novel’ means, ‘a conclusion no-one else has pointed out before’, fair enough.

    If ‘novel’ means ‘an unexpected or counter-intuitive conclusion’, I wouldn’t agree.

    Saturation of the demand for *anything* is to be expected eventually. The question of interest for planning purposes is, how far off is it?

  4. Alan
    another good article – inconvenience (and cost) are the reasons why – a trend which will increase and even accelerate
    it will change the way we work and where we work too
    visit my matusikmissive blog site too
    we often cover the same ground, i from a largely Qld perspective
    cheers for now
    michael

  5. […] relative to the existing fleet, by 2016. I’ve previously discussed how the rate of growth in per capita car travel has been slowing for some time in Australia (and other western countries) and has actually declined […]

  6. […] The usual suspects called on to explain these trends include increases in the price of petrol, in traffic congestion, in parking costs, and in the level and quality of public transport. Also, baby boomers are getting older (and hence driving less) and the long distance drive has increasingly been replaced by cheap air fares. […]


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