Vehicles travel on Interstate 395 (I-305) next to a building construction site in Washington, D.C., U.S. (Photographer: Andrew Harrer/Bloomberg)

Signs on the Road to Peak Auto

(Bloomberg View) -- Americans drove 282.3 billion miles in June, the Federal Highway Administration reported Monday. That set a record. If normal seasonal patterns hold, we'll find out next month that it was broken again in July. After a rare dip during and after the Great Recession, driving is back, big time:

Signs on the Road to Peak Auto

Then again, it shouldn't be all that surprising when the U.S. sets records in vehicle miles driven, given that the U.S. is constantly setting records in population. Perhaps adjusting for the size of the driving-age population would be more informative.

Signs on the Road to Peak Auto

By that measure, we're nowhere near setting records. Also, interestingly, the decline in miles traveled set in well before the recession, with the all-time peak coming in June 2005. It did get much steeper at the end of 2007 -- clearly, the worst economic downturn in 75 years was a big factor in keeping people off the roads. But it seems like there might be secular forces at work, too. As someone who keeps looking for signs that we've hit peak automobile, that's what interests me.

What could those secular forces be? The most talked-about has been the rise of the millennial generation -- generally counted as those born in the 1980s and 1990s, although the cutoff dates vary. They're not that into cars and suburban houses, Derek Thompson and Jordan Weissman wrote in a famous Atlantic article in 2012. Since then, as Thompson acknowledged in 2015, a lot of millennials have bought cars and moved to the 'burbs as the job market strengthened and gas prices dropped. On the other hand, they still buy fewer cars on a per-person basis than baby boomers and generation-Xers, are less likely to have driver's licenses than earlier generations, and are more likely to walk, bike or take public transportation to work than those 35 and older.

Another important factor has to be the aging of the giant baby boom generation. Average annual miles per driver peaks in ages 35 to 54, and falls off pretty sharply after that. The first of the baby boomers turned 55 in 2001; they're turning 70 this year.

A related development is the decline in the employment-to-population ratio since 2001. That's a product partly of the aging of the population, partly of young people staying in school longer, and partly of lots of Americans simply giving up on finding jobs. People who don't have jobs to commute to tend to drive less. So what happens when you divide the number of miles traveled by the number of employed people?

Signs on the Road to Peak Auto

That definitely puts us closer to the all-time peak than the previous chart. The decline in the percentage of adult Americans with jobs to drive to does appear to be a major factor depressing driving. But it's not the only factor. Before 2005 there was a pretty steady upward trend in miles driven per worker. Since then, not so much.

That trend break doesn't mean that we've hit peak auto in the U.S. (and we're certainly nowhere near reaching it globally). But it is pretty interesting, no?

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.

  1. I used the Bureau of Labor Statistics's monthly estimate of the civilian noninstitutional population (that is, excluding uniformed military, prison inmates and such) ages over.

  2. Telecommuters don't have to drive to work either, and there was a rise in the percentage of Americans working from home between But it doesn't seem like a big enough rise to have made much of a dent in the driving numbers.

  3. I got the idea for this chart from  Yonah Freemark

To contact the author of this story: Justin Fox at

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