The real cost of housing is significantly higher than we think when transportation is factored into the equation, according to a joint study by the Center for Neighborhood Technology and the Center for Transit Oriented Development.

These organizations have developed a database that measures affordability in 52 major metropolitan areas around the country. Its interactive maps show the cost of housing alone as a percentage of income and then the cost of housing plus transportation as an income percentage.

The farther from public transportation a community is located the higher its cost of living. In some cities, the cost of housing is less than 30 percent of income, but when transportation is added in the costs can be as much as 65 percent of income.

"Gasoline at $1 and gasoline at $3 are whole different worlds," says Dave Van Hattum, program manager for the St. Paul-based Transit for Livable Communities. "This (Web site) map brings it home to people."