Schedule Coordination in a Multiple Hub Transit Network
Ching-Jung Ting1 and Paul Schonfeld, F.ASCE2
Abstract: The timed transfer concept, which seeks to schedule vehicles from various routes to arrive at some transfer stations simultaneously ͑or nearly so͒, can significantly improve service quality in transit networks. It has been implemented in some cities but with
insufficient efforts to optimize coordination among connecting routes. Our problem is to optimize the headways and slack times jointly for
timed transfers to minimize the total costs of operating a multiple-hub transit network. In this paper, a heuristic algorithm is used to
optimize the headways and slack times for all coordinated routes. Here, headways are integer multiples of a base cycle to ensure that
vehicles on different routes can operate in phase and arrive nearly simultaneously at transfer stations. The results show that as demand
decreases, optimized headways increase and the net benefits of coordinated operation also increase. For routes with significantly different
demand or route length, coordination with integer-ratio headways is preferable to a single common headway. The sensitivity of the transit
service characteristics to various demand and cost parameters is discussed. The results also show that the optimized slack times for routes
vary with such variables as headways, vehicle arrival-time variance, transfer volumes, and passenger time values. For routes with high
standard deviations of arrivals, it is not worth attempting schedule coordination.
CE Database subject headings: Transportation networks; Scheduling; Coordination; Time factors.
One of the main objectives of public mass transit companies in
providing service to passengers is the users’ convenience. In metropolitan areas, conventional public transit cannot economically
provide direct service among all origins and destinations, especially when and...