Beschreibung:
Traditional rail rapid transit systems are primarily limited to central cities, but a modern variant, regional rapid transit (RRT), extends far enough into suburbs to be considered truly regional in scope. RRT uses automatic train driving, other advanced technologies, long station spacing, and park-and-ride lots to serve suburban as well as city travel. Inaugurated between 1969 and 1979, RRT operations in several regions (Philadelphia, Pennsylvania; Boston, Massachusetts; San Francisco, California; Washington, D.C.; and Atlanta, Georgia) combined advanced rapid transit technology with station spacing and market functions akin to inner-zone to midrange commuter rail. To establish similarities and differences between the properties of RRT and other rail systems, data are analyzed for these and other rapid transit systems, as well as for historically established commuter railroads. RRT operations today face challenges of aging infrastructure but continue to be vital in the areas that they serve and have undergone incremental expansion in some instances.