7 research outputs found
Traffic flow on realistic road networks with adaptive traffic lights
We present a model of traffic flow on generic urban road networks based on
cellular automata. We apply this model to an existing road network in the
Australian city of Melbourne, using empirical data as input. For comparison, we
also apply this model to a square-grid network using hypothetical input data.
On both networks we compare the effects of non-adaptive vs adaptive traffic
lights, in which instantaneous traffic state information feeds back into the
traffic signal schedule. We observe that not only do adaptive traffic lights
result in better averages of network observables, they also lead to
significantly smaller fluctuations in these observables. We furthermore compare
two different systems of adaptive traffic signals, one which is informed by the
traffic state on both upstream and downstream links, and one which is informed
by upstream links only. We find that, in general, both the mean and the
fluctuation of the travel time are smallest when using the joint
upstream-downstream control strategy.Comment: 41 pages, pdflate
One-dimensional Particle Processes with Acceleration/Braking Asymmetry
The slow-to-start mechanism is known to play an important role in the
particular shape of the Fundamental diagram of traffic and to be associated to
hysteresis effects of traffic flow.We study this question in the context of
exclusion and queueing processes,by including an asymmetry between deceleration
and acceleration in the formulation of these processes. For exclusions
processes, this corresponds to a multi-class process with transition asymmetry
between different speed levels, while for queueing processes we consider
non-reversible stochastic dependency of the service rate w.r.t the number of
clients. The relationship between these 2 families of models is analyzed on the
ring geometry, along with their steady state properties. Spatial condensation
phenomena and metastability is observed, depending on the level of the
aforementioned asymmetry. In addition we provide a large deviation formulation
of the fundamental diagram (FD) which includes the level of fluctuations, in
the canonical ensemble when the stationary state is expressed as a product form
of such generalized queues.Comment: 28 pages, 8 figure