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

This article presents the general concepts , mod- els, 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 de- veloped software integrates dial-a-ride routing and schedul- ing principles and practical experience and explicitly con- siders travel time variability in urban roadway networks . Such extensive and complex integration has been made pos- sible by improved data acquisition and processing capabil- ities 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 effi- ciently to paratransit user requests. A real scheduling prob- lem from the city of Edmonton , Alberta, where the system was tested, is used to illustrate the positive computational expe- rience and the capability of the developed software to handle both off-line and on-line operations .