Sang Nguyen, Université de Montréal
|Modeling passengers assignment on transit networks
|On a transit network, a passenger who boards a carrier and finds a
seat can keep it until he gets off the carrier. This seemingly innocuous
first come - first served rule significantly enhances the difficulty of
modeling the passengers assignment on a transit network, where arriers have
rigid capacities, as an equilibrium multicommodity flow problem. Two
distinct modeling approaches, a path flow based on the notion of
available capacity and a strategic flow with loading priorities,
giving rise to different variational inequality formulations will bediscussed.
Both theoretical and computational insights will be presented.
Paolo Ferrari, Università di Pisa
|Road pricing, public transport and users' welfare
|Guido Gentile, Università di Roma "La Sapienza"
|Rethinking the wait model at transit stops
||Consider a transit network with common lines in which passengers' behavior
is based on line frequencies, instead of their timetables. The classical
assumption is that the passenger will board the first arriving carrier among
the lines which are perceived to be attractive.
In almost all the models proposed in the literature and widely adopted to
plan transit systems the attractive set has been considered static, e.g., it
is not modified during the wait. This approach is not consistent with the
rational behavior assumption. Indeed, passengers decide whether it is
convenient to board an arriving carrier rather than to pursue waiting for a
better subsequent arrival, taking into account the time already waited at
the stop. So, a line can be attractive at a given waited time, and not
necessarily for the entire waiting process, yielding a dynamic attractive
set model. The static approach is valid only when the headway distribution
of all the lines is exponential, since in this case there is actually no
temporal evolution of the attractive set; though the exponential
distribution is quite unrealistic.
Moreover, when on-line information on future arrivals of buses are posted at
a stop, passengers may choose to board a line that offers the best
combination of displayed time and expected travel time to destination once
We propose in this paper a general framework for determining the probability
of boarding each available line at a stop and the corresponding expected
waiting and travel times, with and without on-line information.