ABSTRACT
The motivation for the second foci arises from a problematic component of Egged Israel’s national bus carrier cooperative, which is presently engaged in scheduling about 4000 buses over some 2000 routes. Egged operates over an extensive geographical network composed of urban, suburban, regional, and intercity routes and performs an average of 50,000 daily trips-one of the world’s largest schedules. Egged’s crucial component of scheduling buses to trips was performed manually by about 60 schedulers using Gantt charts. A scheduler’s duty was to list all daily chains (some DH) for a bus, ensuring the fulllment of the timetable and the operator’s requirements (refueling, maintenance, etc.). However, because of frequent changes in the schedule and frequent additional imposed trips, the skilled schedulers were not capable of handling the busscheduling tasks efciently. Consequently, the Egged management decided to test a fully computerized system. Their experience with this system is shown in Section 6.3. The experience led to the development of an informative graphical method, to be explicated in Sections 6.5 and 6.6.
