Modeling Cost and Passenger Level of Service for Integrated Transit Service

Abstract

In the United States, many transit agencies are considering integrating their demand-responsive service with traditional fixed-route service. In some cases, it may be advantageous to the transit agency or to the passenger to coordinate traditional demand-responsive transit service with fixed-route service. The demand-responsive service connects passengers from their origin to the fixed route service and (or) from the fixed route service to their final destination. Such a service is expected to reduce the cost of transit service, but also will affect the level of service experienced by passengers. The integrated transit service problem is to schedule both passenger trips (or itineraries) and vehicle trips for this service. In considering the literature, this research proposes a scheduling method that explicitly incorporates both transit agency cost and passenger level of service. More specifically, the model assumes: (i) a fixed-route bus schedule; (ii) desired passenger pick-up and drop-off points; (iii) time window constraints for passenger pick-ups, drop-offs, and transfers; and (iv) passenger level of service constraints, including maximum travel times and number of transfers. Using this information, the proposed technique determines which trips are eligible for integrated service using the passenger level of service constraints. A schedule is then created for both the passenger trips and the vehicle trips, so that the total cost of service is minimized. The method is illustrated using a case study of transit service in Houston, Texas, showing the possible cost advantages and changes in passenger level of service with integrated service. The contributions of the research include: (i) a new heuristic for scheduling integrated transit trips that accommodates both passenger and vehicle scheduling objectives; and, (ii) an illustrated method for evaluating the operating cost and passenger level of service implications of integrated transit service.