Joseph Stromberg at Vox.com has an article up arguing that “commuting alone by car” is “associated with obesity, high blood pressure, sleeplessness, and general unhappiness” relative to other transportation modes. His solution to unhealthy lengthy commutes is to increase carpooling.
Back in 2012, I argued against another now-Voxxer, Matthew Yglesias, on the supposed health harms of auto commuting. The problem, as Census data make clear, is that other than those who walk to work, people commuting by driving alone generally have the shortest commutes. Those using public transit take on average twice as long to make their commuting journeys as those who drive by themselves.
With that core fact in mind, let’s continue with Stromberg’s article. To support his claims about allegedly unhealthy car commuting, he cites the following 10 studies:
- Lopez-Zetina, Lee, Friis, “The link between obesity and the built environment. Evidence from an ecological analysis of obesity and vehicle miles of travel in California” (2006)
- Lindström, “Means of transportation to work and overweight and obesity: a population-based study in southern Sweden” (2008)
- Hoehner et al., “Commuting Distance, Cardiorespiratory Fitness, and Metabolic Risk” (2012)
- Christian, “Opportunity Costs Surrounding Exercise and Dietary Behaviors: Quantifying Trade-offs Between Commuting Time and Health-Related Activities” (2009)
- Hansson et al., “Relationship between commuting and health outcomes in a cross-sectional population survey in southern Sweden”
- Gottholmseder et al., “Stress perception and commuting” (2009)
- Walsleben et al., “Sleep Habits Of Long Island Rail Road Commuters” (1999)
- Office for National Statistics, “Commuting and Personal Well-being, 2014” (2014)
- Flint, Cummins, Sacker, “Associations between active commuting, body fat, and body mass index: population based, cross sectional study in the United Kingdom” (2014)
- Stutzer and Frey, “Stress That Doesn't Pay: The Commuting Paradox” (2004)
That’s a lot of evidence supporting the claim that automobiles are making us unhealthy, right? Wrong. Out of all of these studies, only Flint, Cummis, Sacker (2014), Christian (2009), Lindström (2008), and Lopez-Zetina, Lee, Friis (2006) made explicit comparisons between transit and auto commuting. The majority of the studies Stromberg cites as evidence of the dangers of driving alone to work found longer commutes—regardless of the mode—were associated with negative well-being.
For more on why the Hoehner et al. (2012) study is very limited and doesn’t lend itself to broad national conclusions, see my write-up of it after it was published.
Christian (2009) finds a positive relationship between commute times and obesity, similar to the results of Lopez-Zetina, Lee, Friis (2006) and Walsleben et al. (1999). However, as Christian notes, “Commute length may be associated with body mass due to either causality or self-selection.” This is to say, we don’t know if long commutes make us fatter or if fatter people make decisions that lead to long commutes. This is a classic correlation-does-not-equal-causation point.
Where does all of this leave us? I suggest the following takeaways:
- Transit commutes are the longest commutes;
- Driving alone results in the shortest commutes after walking;
- Long commutes are associated with worse health outcomes; and
- Unhealthy people may make choices that lead to long commutes.
While not directed at this Stromberg piece, I personally find it hilarious that transit boosters implicitly accept that the direct mobility benefits of transit are so low that they need to fling every possible co-benefit spaghetti at the wall in order to justify unjustifiable mass transit subsidies. But to you who drive alone to work and are now scared your car is secretly killing you, don’t worry. It’s the transit riders with commutes twice as long as yours who may need to worry.