Is Driving to Work in Decline?

Over at The Washington Post's Wonkblog, urban affairs reporter Emily Badger has a post up on the recently released U.S. Census Bureau American Community Survey 2013 commuting data. The title of the post, "The share of Americans driving to work is declining for the first time in decades," seems to suggest that a smaller share of commuters are driving themselves to work. Badger relies almost exclusively on a Brookings Institution blog post that makes similar claims.

However, what neither blog post mentions is that between 2007 and 2013, the share of Americans driving to work alone actually increased.

While the Brookings authors at least note that "the vast majority of [those commuting by private automobile] travel alone rather than in a carpool," they don't point to the large decline in carpooling as a major source of the slight decline in private vehicle commuting. Below is a table containing the 2007 and 2013 ACS data cited by Brookings (and reblogged by Badger):

  Workers Drive Alone Carpool Car Total % DA % CP % Car Total
2007 139,259,684 105,954,656 14,487,532 120,442,188 76.1 10.4 86.5
2013 142,962,379 109,277,215 13,387,020 122,664,235 76.4 9.4 85.8

As we can see, while Badger is correct to note that "[t]he share of Americans who get to work in a private car has declined since 2007, from 86.5 percent in 2007 to 85.8 percent," she fails to mention that the share of American commuters who drive alone increased during that same time period, from 76.1 percent to 76.4 percent. Nor does either Brookings or Badger mention that carpooling saw this largest mode-share decline during this period, dropping from 10.4 percent in 2007 to 9.4 percent in 2013.

Although the share of commuters driving alone is below the 77 percent peak in 2005, teasing out a trend from these limited data is probably not a worthwhile endeavor. This is particularly true given the continued weak economic recovery. But one thing is certain: discussing private vehicle commuting trends without examining the composition of private vehicle commuting at best presents a misleading picture.