AN INTEGRATION OF NETWORK DATA MODEL AND ROUTING ALGORITHMS FOR ONLINE TRANSIT TRIP PLANNING

Algorithms for transit network analysis are much less developed than those for highway networks. With the growing demand for online transit information services and trip itinerary planning, there is a great need for efficient path finding algorithms. Many existing algorithms are based on shortest path algorithms for highways. But a path finding algorithm for transit network is much more complex than that for a highway network because it is determined by transit schedules and involves transfers. This paper presents routing algorithms for online trip itinerary planning on transit networks, including forward searching (from origin to destination with known trip start time) backward searching (from destination to origin with expected arrival time), and minimal transfer paths. The algorithms take into account unique characteristics of the transit network such as schedule variations of time of day and days of the week, multiple bus routes on the same street, walk time of a transfer. A transit network topology has been developed that was based on a relational database structure to increase network-searching efficiency