Longer commutes disadvantage African-American workers

That can be a 25 percent increase over an average urban two-way commute of about an hour, she found, based on a study of 2011 U.S. Census Bureau data.

"Because of racial segregation, blacks spend more time getting to work. For low wage workers, the difference is seven minutes each way when compared with whites with similar jobs," she said.

"The ability of workers to access jobs via a robust transportation system is positively associated with intergenerational economic mobility. In Chicago, African Americans continue to experience pronounced spatial disadvantage as a result of historic racial residential segregation and a jobs-housing mismatch," she explained.

Parks presented her work in a paper, "Density for All: Linking Urban Form to Social Equity," on Feb. 15 at the annual conference of the American Association for the Advancement of Science in Chicago.

The paper was part of a session "The Future of the Cities: Dense or Dispersed?" that explored the advantages and challenges of increasing density in urban life. Although overcrowding can be a problem, dense cities also offer opportunities for better use of technology, reduced commuting time, and positive environmental impacts, scholars pointed out.

"In order to encourage equity in denser cities, we also need to be aware of the needs of lower wage workers," said Parks, who holds a Ph.D. in geography and also studies low-wage work. Improved transportation and reduced housing segregation would help, she said.

In cities such as Chicago, low-wage African American workers frequently have to travel long distances outside their neighborhoods to find work as few service and other low-wage employment opportunities are available in their communities. The result is more expense on public transit and automobile costs, she said.

For blacks overall, the difference in travel time with white commuters is four minutes each way. There is little difference in commute times among whites, Latinos and Asians.

In studying commuting, Parks found the longest commute among 95 percent of all workers is 65 minutes each way. Higher paid workers are willing to spend more time and money on longer commutes, she said.

Women usually have shorter commute times than men as they seek jobs closer to home. That preference may limit their job opportunities. Black women have the longest commutes of any group by far, traveling roughly eight minutes longer each way to work than white women with similar jobs.

"Urban sprawl currently reduces employment opportunities for lower-skill workers and women and dampen the economic mobility prospects for the poor," she said. "Density may counteract these effects, but only as part of a comprehensive jobs, housing, and transportation urban system."