Improving Bus Passenger Transfers on Road Segments through Online Operational Tactics

The use of transfers in public transit has the advantages of reducing operational costs and introducing more flexible, efficient route planning. The main drawback from the passengers’ point of view is the inconvenience of traveling multilegged trips. To diminish the waiting time caused by passenger transfers, synchronized timetables were introduced. The use of these timed transfers, however, creates uncertainty about the simultaneous arrival of two (or more) buses at an existing stop, which can lead to a deterioration in system reliability. To alleviate this uncertainty about simultaneous arrivals, a new passenger transfer concept was developed that extends the commonly used single-point encounter (at a single transit stop) to a road segment encounter (with any point along the road segment constituting a possible encounter point). The objectives of this work are as follows: (a) to define the bus-encounter probability along a road segment, (b) to introduce a simulation model to estimate the bus-encounter probability, (c) to model the bus-encounter probability upper bound, which is a major input to a dynamic programming model that optimizes the total travel time, and (d) to present simulation results that confirm the benefits of such a system. It is believed that the proposed concept will reduce the uncertainty of two buses meeting at a point, as well as reduce the average travel time and enable more flexibility in deploying online operational tactics (e.g., holding buses, skipping stops, slowing down).