Why Johnny Can't Eat
The reason for this dissonance between the reality in America's streets and official poverty data is the federal government's reliance on the concept of the poverty line... Over the last 40 years, the federal poverty level has been updated to reflect inflation, but not social and economic changes. For most families today, food constitutes less than a fifth of their budgets while higher costs of transportation, housing, health care and child care have created new burdens....Despite all evidence to the contrary, the federal poverty level measurement also assumes that costs are the same across all of the lower 48 states... A family living in Manhattan in New York is expected to spend the same amount of money on food, clothing and shelter as a family in the town of Manhattan in Kansas.
Note the bit about transportation costs. Suburban Nation shows what a burden having to pay for a car (or multiple cars) can be on working families. Public transportation is essential to help poor people be self-suffient.
This article makes a convincing case that America's poverty measure needs to be revised. I can't believe it doesn't take cost of living into account!