It's easy to reduce commuting to a simple measure of getting to and from work, but its residual impact on our personal lives is becoming clearer every day. Commuting causes us stress and general displeasure, which no doubt sours many a mood and stirs up many a marital argument, though the side-effects aren't all bad. As we reported last spring, couples who commute in the same direction actually (if oddly) have happier marriages.
New evidence suggests that commute times may influence whether or not married women work at all. In research set for publication in the Journal of Urban Economics, a trio of scholars led by Dan Black of the University of Chicago reports that cities with longer average commutes have lower rates of married women in the workforce. The results suggest that commuting, above and beyond other factors, drives the disparity in the female labor force found across major American cities:
We believe that many factors are at play in producing the large observed local variation in female labor supply across the U.S., but, we argue, one explanation stands out: Married women, particularly married women with young children, are very sensitive to commuting times when making labor force participation decisions.
The research was inspired by the wide variation in married women workers that exists in U.S. metropolitan areas — a trend that's gone "largely unnoticed," according to Black and company. (For the purposes of the study, the female population consisted of white women, age 25 to 55, with a high school education.) At the high end of the spectrum is Minneapolis, where 79 percent of women were employed as of the 2000 Census. At the low end is New York City, where that was true of only 52 percent.
Some of the other metros with a large female labor supply included Milwaukee (78 percent), Greensboro (77 percent), and Rochester (75 percent). Some of those at the small end included Honolulu (55 percent), Los Angeles (59 percent), and Miami and Houston (61 percent). Other notables, in ascending order, were San Francisco (62 percent), Chicago (67 percent), Atlanta (68 percent), Philadelphia (69 percent), Boston (71 percent), Washington, D.C. (73 percent).
There are any number of possible explanations for the great range found here, but Black and colleagues believe none of the most obvious ones are sufficient. Local housing prices don't explain it, they say, because women are no more likely to work in expensive cities where additional income might be help pay the rent or the mortgage. Neither local wages nor unemployment rates seem to be the key factor, either. Even child care costs only tell part of the story, since there's great metro area variation among married women workers who don't have kids, too.
So the researchers focused their analysis on commuting in 50 big metros across the United States. They compared average two-way commute times across several decades with the size of the female labor force in these cities over that same period. On the whole they found that every additional minute of commuting led to a .3 percent drop in the rate of working wives. That means for every half hour difference in commute time between cities, you might expect about a 10 percent gap in the married female labor force.
When the researchers separated women into several groups, that trend varied in degree but not in kind. The effect was largest for women with young children (under age 5), where a 1-minute commute decreased the probability of working by half a percent, followed by women with older children. Women with no children displayed the effect to a smaller magnitude, as did women with college degrees. Black and colleagues also found that as commute times rose within a particular metro, the female labor force grew more slowly.
So what's going on here? The researchers can't quite say for certain, though they do offer some speculation. Since women are the ones who traditionally bear most household responsibilities, the overall cost of working far from home — measured in time and energy as well as money — is even greater for them than it is for men. In other words, it's not just the commute itself that may discourage married women from working, it's also the extra effort needed to get other places (e.g. school or the store) later in the day.
Again, that's just a theory, and no doubt one that will be adjusted as the question receives more attention. But the upshot of the results themselves is quite clear, and it's also in line with so much other emerging behavioral evidence: city traffic has a ripple effect on personal decisions and general well-being. All the more reason to reduce it in every way possible.