Affordability has never been just about housing costs. Researchers have long known that it’s the interaction between housing and transportation costs that provides a more meaningful measure of affordability. This is especially true now that transportation costs have increased to an average of 19 percent of household income -- up from 3 percent in the 1920s.
Transportation is now the second highest household expenditure after housing, and gas prices are expected to continue driving that cost up. Communities in Southern California are especially vulnerable as the foreclosure crisis indicates -- since residents drive so much.
The affordability index is a new tool to measure the true affordability of housing choices by combining housing and transportation costs (H+T) in a neighborhood or region and dividing that number by income. Interestingly, the index shows that H+T costs vary significantly: households living in neighborhoods that are relatively dense,…