Transit service area is the basis of several direct-demand models of single-route ridership. This service-area concept has not been integrated into the more recent single-route models that have evolved from the Urban Transportation Planning System and similar four-step simulation procedures. How the service area concept was incorporated into the Transit Ridership Forecasting Model is explained and the application of the concept on routes selected from the Milwaukee urban area is illustrated. It is shown that use of the service-area concept removes a serious tendency for four-step models to underestimate ridership on marginal routes. It is also shown that proper application of the service-area concept can reduce both computation time and data requirements.
Abstract