Abstract (EN):
A queuing system resulting from a semaphorized intersection regulated
by semi-actuated control in a network urban traffic is considered. Modelization of
the queue length and of the delay of vehicles is crucial in the study of the performance
of intersections equipped with traffic signals. In these systems, the server
(green signal) is desactivated (red signal) during a random period of time. Due to
this particularity, models for classic queues such as M/M/1, M/G/1 and G/M/1
are not appropriate. In the urban traffic literature, the frequent desactivation of
the server as well as the variation of the service period are not well formulated. In
the present work a M/G/1 queue where the server occasionally takes vacations and
the service discipline is a non-gated time-limited policy is analyzed. The present
analysis follows [Leung and Eisenberg, 1991] who consider an application of these
models in telecommunications. Their implementation, given its complexity, is made
possible by using Laguerre functions when looking for an approximate solution of
the differential equations involved. One concludes that the mean delays of vehicles
given by this model are slightly smaller than those obtained by simulation procedures,
but they are able to give us a good approximation for larger flows, which is
of interest for traffic engineers, since, in that case, the approximations one can find
in the traffic literature are known not to be adequate.
Language:
English
Type (Professor's evaluation):
Scientific
No. of pages:
8