Route Choice on Transit Networks with Online Information at Stops

Passengers on a transit network with common lines are often faced with the problem of choosing between either to board the arriving bus or to wait for a faster one. Many assignment models are based on the classical assumption that at a given stop passengers board the first arriving carrier of a certain subset of the available lines, often referred to as the attractive set. In this case, it has been shown that if the headway distributions are exponential then an optimal subset of lines minimizing the passenger travel time can be determined. However, when on-line information on future arrivals of buses are posted at the stop it is unlikely that the above classical assumption holds. Passengers may choose in this case to board a line that offers the best combination of displayed waiting time and expected travel time to destination once boarded. In this paper, we propose a general framework for determining the probability of boarding each line available at a stop when on-line information on bus waiting times is provided to passengers. We will also show that the classical model without on-line information may be interpreted as a particular instance of the proposed framework. The impact of the availability of information regarding bus arrivals and that of the regularity of transit lines on the network loads as well as on the passenger travel times will be illustrated with small numerical examples.