Expensive transport. In Houston, whose residents spend 3 percent more than the national average on housing, the average resident devotes 21 percent of his household expenditures -- $9,722 annually -- to transportation. Although most of it comes from the car itself: repairs, insurance, financing and so on, gasoline accounting for a mere 17 percent, Americans are content to gripe about the only part of commuting that's still cheap: the gas.