Buyers who move deep into the suburbs to find bigger, nicer houses often fail to consider added transportation expenses that might bust their budgets, a new national study has concluded.

Rising transportation costs are dramatically shrinking the amount of affordable housing in Pittsburgh and across the U.S., according to the report released today by the nonprofit Center for Neighborhood Technology, a group that promotes more environmentally conscious policies.

Based on housing costs alone, 72 percent of neighborhoods in the Pittsburgh metropolitan area would be considered affordable to those making the median income. But when transportation expenses are factored in, the number drops to 32 percent.

Nationally, only 40 percent of neighborhoods are affordable to typical families when transportation costs are included, the report said.

"This is an issue critical to the future of the middle class," said Nick Turner, managing director of the Rockefeller Foundation, which helped finance the research.

The authors recommended steps to make buyers more aware of transportation costs, and changes in public policy that encourage more dense development and better transit options.

"Combined housing and transportation costs are lower in central cities that have mixed residential and commercial neighborhoods, a wide range of transportation options and pedestrian-friendly streets," they said.

One recommendation is mandatory disclosure of the average transportation cost for a neighborhood as part of the home-buying process.

"Americans will make a better housing decision by having more information," said Ron Sims, deputy secretary for the U.S. Department of Housing and Urban Development, at a briefing Tuesday unveiling the study.

It covered 337 metro areas that comprise 161,000 communities and 80 percent of the nation's population.

The authors said the traditional method of evaluating housing affordability -- that it should cost 30 percent or less of a household's income -- is flawed. It recommended a threshold of combined housing and transportation costs that consume 45 percent or less of a family's income.

The report cited a "drive 'til you qualify" trend that pushes people farther away from core cities and employment centers to find housing they can afford.

Drawing contrasts in the Pittsburgh region, it said a typical family living in Lower Burrell in Westmoreland County spends about $400 a month more on transportation than one in the Duquesne Heights section of Mount Washington.

Transportation costs eat up nearly 26 percent of the typical household budget in Harrison, 19 percent in Dormont and less than 15 percent in the Crawford Square community in the lower Hill District, the report said.

In interviews Tuesday, local real estate professionals said that while most prospective buyers place a premium on location and convenience, they rarely do the math on transportation expenses.

"The people who want to live way out in the boonies, they know they're going to travel. They know there's a cost to it," said Nancy Mathews, manager of Northwood Realty Services' North Hills office.

Buyers typically will say "don't take me more than 30 minutes from Downtown" and "how far am I from shopping, schools, work? They're so savvy about it," she said.

Linda Carnevali, regional manager for Prudential Preferred Realty, said in 23 years she had never seen a prospective buyer compute transportation costs.

Buyers pay attention to neighborhood quality, average home prices, taxes and proximity to schools, work and family members. "It's more the convenience than the cost factor," she said.

If the government enacts laws or regulations requiring disclosure of average transportation costs, "we would be happy to provide it," Ms. Carnevali said.

Mr. Turner of the Rockefeller Foundation said with the U.S. population expected to grow by another 100 million by mid-century, there's a need to reduce dependence on foreign oil and carbon emissions and build better transportation networks.

Over the past 50 years, $4 of every $5 in federal transportation funding has been spent on roads, he said.

"The almost exclusive focus on roads has limited the amount of choice," said Scott Bernstein, president of the Center for Neighborhood Technology, which bills itself as a "think-and-do tank" that promotes environmental improvements, a stronger economy and equity.

Of the 337 metro areas in the report, only three showed a gain in affordable neighborhoods when transportation costs were factored in along with housing costs -- San Jose, San Francisco and New York.

The data is posted at htaindex.cnt.org.

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