On‐Line and Off‐Line Routing and Scheduling of Dial‐a‐Ride Paratransit Vehicles

This article presents the general concepts, models, and computational techniques applied in a new dial-a-ride vehicle routing and scheduling system. The objective of this system is to improve the responsiveness, reliability, and productivity of dial-a-ride paratransit services. The developed software integrates dial-a-ride routing and scheduling principles and practical experience and explicitly considers travel time variability in urban roadway networks. Such extensive and complex integration has been made possible by improved data acquisition and processing capabilities of computer, telecommunications, and vehicle location technologies. Advanced computational methods applied in the system, such as the artificial neural network technique, which allows heuristic estimation of origin-destination travel times in a dynamic and stochastic fashion, contribute to the processing speed required to respond expeditiously and efficiently to paratransit user requests. A real scheduling problem from the city of Edmonton, Alberta, where the system was tested, is used to illustrate the positive computational experience and the capability of the developed software to handle both off-line and on-line operations.