The complete cost of housing: Your mortgage plus your gas tank

Access to the American Dream has always been the great promise of suburban development. By settling in the outer reaches of the metro area (this once meant Como Park, then Roseville, now Hugo), a family can own a relatively sprawling lawn and a relatively sizable house for a lot less than the same setup would cost on, say, Summit Hill or Lowry Hill. But there has always been a hidden cost to suburban living: transportation. The Chicago-based Center for Neighborhood Technology (CNT) has created a new set of maps that visually illustrate how recent years' rising fuel prices have affected the cost of living—and how suburbanites are feeling the worst pain.

The maps are based on what CNT is calling a "housing and transportation affordability index," which takes account of the combined costs of housing and transportation (for most residents of the suburban Twin Cities, this means auto fuel). In the above map, for example, blue shading indicates areas where the average household spends over 48% of its income on housing and transportation combined—in other words, where half or less of the average household's income is available for food, health care, savings, education, and everything else besides gas and mortgage payments.

CNT has also created a set of maps that demonstrate the impact of rising fuel prices over the past eight years. The colors on this map correspond to proportions of household income devoted to transportation. In areas shaded pink, the average household spends over 20% of its income on transportation; in areas shaded red, it's 28% or more.

And that was in 2000. Here's how the situation looks in 2008:According to the progressive think tank, its goal in building these maps was to refocus the discussion about housing affordability—broadening the discussion beyond the cost of housing itself to consider "the intrinsic value of place." See CNT's Web site for more information, including more maps of the Twin Cities and several dozen other U.S. metro areas.

Jay Gabler is assistant editor of the Daily Planet.