Aggregate Vehicle-Miles Traveled in the United States under Several Scenarios of Future Travel Growth, 1946-2040 (source: U.S. PIRG)

A new report by the US consumer group Public Interest Research Group (U.S. PIRG) provides further confirmation of a significant drop in the amount of driving done by Americans, especially millennials (born 1983-2000).

The report, A new direction: our changing relationship with driving and the implications for America’s future, finds that although driving consistently increased between 1945 and 2004, Americans now drive no more per capita than they did in 1996, and no more in total than they did in 2004.

Millennials are a primary cause of the new trend, according to U.S. PIRG. Those aged 16 to 34 years drove 23% fewer miles on average in 2009 than the corresponding cohort did in 2001. They also use public transport more and are more inclined to live in the central counties of metropolitan areas than their predecessors.

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This is a trend I’ve discussed before (e.g. here and here), noting there’s only limited information on the type of travel that’s changed; there’s a large range of possible explanations; and millennials are only one group contributing to the trend.

U.S. PIRG argues that investment in transport needs to shift away from road to public transport and cycling to reflect the new reality. However a recent article by Robert Poole from the Reason Foundation is notable because, while it doesn’t dispute the reduction in driving, it questions the influential role attributed to millennials.

Mr Poole contends that the consumer group overstates the extent to which millennials are anti-car and anti-suburb – he thinks the change is largely due to the recession and hence is likely to be temporary:

  • A Pew Center study in 2010 found 37% of young respondents either out of work or underemployed.
  • For those aged 16-24, employed males averaged 12,000 miles in 2009, compared with about 6,000 miles for unemployed males.
  • The fraction of those aged under 19 years with drivers licenses was essentially flat from 2001 to 2009.
  • The number of people aged 15 to 34 living with their parents soared from 0.5 million in 2008 to nearly 2 million in 2011.

He also says the rate of household formation has stagnated since 2007 because fewer young people are getting married, having children, and buying homes due to the recession. He expects all these trends will likely reverse as the economy recovers.

Mr Poole also questions the claim that millennials are shifting to public transport and the centre of cities in significant numbers. Recent research, he says, shows that “increased transit use accounts for only about 1% of the decrease in auto travel, with bicycle and walk trips appearing to account for only a few percent more”. Moreover, in 2000 19% of people aged 20-29 lived in core municipalities of major metropolitan areas, compared to 13% in 2010.

Other factors that Mr Poole suggests also underlie the fall in driving include the growth of online shopping and telecommuting. He concludes that the post-war growth in travel propelled by increasing car ownership and female workforce participation cannot go on indefinitely. Further increases will be limited to the rate of population increase.

But the just-so story about Millennials losing interest in driving appears to be mostly an artefact of the recession’s severe impact on younger people, not a fundamental change in their choices of where to live or how to travel.

Both U.S. PIRG and Reason Foundation are advocacy groups with different ideological positions. It goes with the territory that partisan organisations are inclined to uncritically accept information that accords with their view and ignore evidence that contradicts it.

Nevertheless, there’s always value in hearing both sides to a story. We don’t understand the nature of the reduction in driving very well, much less understand fully the underlying causes. In my view U.S. PIRG overstates millennials’ preference for public transport and density; while Mr Poole doesn’t seem to fully recognise that the per capita fall in driving started well before the GFC.