Network Performance Optimization Using a Queueing Network Model
C Osorio, M Bierlaire, EPFL, CH
We present an aggregate model of urban traffic that explicitly models congestion phenomena such as spillbacks. We illustrate its use in the optimization of traffic signal timing in the city of Lausanne.
In this paper, we present and analyze a new aggregate model of urban traffic. The main
challenge in the formulation of an aggregate model is to analytically grasp the correlation
between the different components of the network while maintaining a tractable model. This
correlation explains congestion effects and quantifies their overall network impact. Our analytic queueing network model captures this correlation and can therefore explicitly model
complex phenomena such as spillbacks. This is useful to identify the sources of congestion
(e.g. bottlenecks) and quantify their effects (Osorio and Bierlaire, forthcoming).
This analytic model fits well within an optimization framework. We illustrate this in the
context of the optimization of traffic signal timing in the network of the city of Lausanne.
The aggregate model is calibrated using the outputs of a disaggregate model, that is a microscopic traffic simulation model. The analytic formulation of this optimization problem
is presented. The optimal solution is then evaluated with the microscopic traffic simulation
model. Its performance is compared with that of several other methods. We show how
these methods differ in their ability to cope with increasing congestion; and emphasize the
importance of taking into account the correlation between consecutive roads.
Association for European Transport