Path-planning algorithms for public transportation systems

Computing travel plans for desired trips in public transportation systems is not exactly the same as finding a shortest driving path in a given area. Path planning in the context of public transportation systems must consider the route constraint that public vehicles serve on particular paths and that passengers cannot order the drivers to change the bus routes. Explicit representation of the route constraint helps us to design efficient algorithms that focus on viable routes for computing travel plans of interest. This paper presents two strategies for capturing the route constraint. The first strategy employs connectivity matrices, and applies special properties of matrices for quickly identifying feasible travel plans for the desired trips. The second strategy uses hubs where many service routes concentrate for computing travel plans. Our algorithms perform very well in field tests.