Schedule synchronization in public transit using the Fuzzy Ant System

Trips between nodes in public transit networks may be made with or without making transfers. Transfers usually represent an inconvenience to passengers. Since poorly coordinated transfers can increase waiting times significantly, it is especially important (when constructing timetables) to synchronize schedules carefully in cases of larger headways. Poorly coordinated transfers can also reduce the number of passengers using public transit as a result of switching to competitor modes. When designing synchronized schedules it is necessary to try to minimize the total waiting times of all passengers at transfer nodes in a transit network. Often only approximate numbers of transfer passengers are known. This paper develops a model for schedule synchronization where the number of transfer passengers is only approximately known. The model is based on the Fuzzy Ant System that represents a combination of the Ant Colony System and Fuzzy Logic.