Edited sentence: A 1956 amendment to the state's constitution requires that all gas taxes be used for highway construction rather than public transit.As a result, the sprawling city, which once boasted the second-largest streetcar system in the United States, now ranks among the leading cities for automobile use (and routinely fails to meet air quality standards set by the Environmental Protection Agency.Birmingham's mass transit system, such as it is, exemplifies the reluctance of the citizens of Alabama to support the redistribution of wealth from the more rural areas to the state's large cities.Partly because Alabama's constitution limits the ability of local governments to tax citizens, and partly because of persistent patterns of economic and racial segregation, Birmingham's public services are direly underfunded.Richard C.Shelby granted $87 million to help fund a regional multi-faceted mass transit system.The US Congress, with the urging of Sen.The county and state have let many deadlines for 20% matching funds pass, and little visible progress is being made toward adequate transit services.The metropolitan area's many autonomous suburban municipalities have left the central city behind with a low tax base and a high demand for services