Is living in an outer-ring suburb, while working in the city, a feasible way to keep costs in check? Don't count on it.

In the Washington, D.C., metro, where many residents move to remote suburbs to find affordable homes, working families spend an average of nearly $23,000 per year on housing and $13,000 for transportation. The combined cost represents nearly 47 percent of the area's median income of $78,000, according to a new report from the Urban Land Institute's Terwilliger Center for Workforce Housing.

"The report confirms our fears about what has been happening to the land-use pattern in the United States," says Richard Rosan, president of ULI Worldwide.

The report, titled Beltway Burden: The Combined Cost of Housing and Transportation in the Greater Washington, D.C., Metropolitan Area, measures the combined housing and transportation costs for 22 areas within the Washington Region. The bottom line: Increases in transportation costs start offsetting housing savings when families live roughly 15 miles to 17 miles from employment centers.

Just last week, The Washington Postreported that residents in Virginia's Prince William County, a D.C. suburb, face the longest commutes in the country. U.S. Census figures show that its residents have an average one-way commute of 46.3 minutes, compared with the national average of 25.1 minutes. The 46.3-minute average is longer than commutes in the New York City, Los Angeles, and Chicago areas.

"The shortage of housing that is close to jobs is a pressing urban need that cannot be shelved for later," Rosan adds. "Throughout urban America, commutes are getting longer, and traffic is getting worse. Improving the quality of life in our cities by linking more housing to jobs is critical to both economic and environmental stability. Where we build is just as important as how much we build."

The report emphasizes the need for policy changes to lower the housing-transportation cost burden for the D.C. metro area?a burden which is only expected to increase due to the projected addition of 1.7 million new households in the region over the next 20 years. Half of that growth is predicted to occur in the outer suburbs.

"Now is the time to put in place policies that are forward-thinking," says Jeffrey Lubell, executive director of the Center for Housing Policy, the research affiliate of the Washington, D.C.-based advocacy group National Housing Conference. "We are so busy putting out fires that I am afraid we are going to miss this opportunity."

Beltway Burden calls for a number of solutions that can be implemented in any city. These include expanding the availability of affordable housing near public transit stops and employment centers; preserving existing affordable stock to ensure permanent affordability; and encouraging employees to either allow more workers to telecommute and/or offer employer-assisted housing.

To complement the report, the Terwilliger Center released a cost calculator, which allows users to input their current home and work addresses and compare their housing and transportation costs to the spending they would incur if they chose to move or change jobs. The Terwilliger Center plans to expand the calculator's computations to cover additional regions of the country.