The United States implicitly subsidizes people who can afford cars by making its main infrastructural investments in automobile transportation. For poor people, public transportation becomes a main means of transportation, but they are forced to pay inflated prices (in terms of time and direct charges) because collective investments in public transportation remain comparatively weak. The scholarship within the transportation field typically focuses on either documenting disparities in transportation use or documenting the effects of those disparities on employment and other life chances.
Who uses public transportation? Are buses and rail transport mainly used by poor people? How many people are too poor to own a car? Do some poor people overspend on cars and compromise on other needs?
Are the high rates of unemployment among blacks and poor people partially explained by the relocation of job opportunities away from urban, industrial city-centers and into suburbs that are less accessible to inner-city residents? How much would unemployment be reduced if car ownership among disadvantaged groups were increased?