  We present in this paper a method for the estimation of traffic state at road
junctions controlled with traffic lights. We assume mixed traffic where a
proportion of vehicles are equipped with communication resources. The
estimation of road traffic state uses information given by communicating
vehicles. The method we propose is built upon a previously published method
which was applied to estimate the traffic in the case where roads are composed
of two lanes. In this paper, we consider the case where roads are composed of
three lanes and we show that this solution can address the general case, where
roads are composed of any number of lanes. We assume the geometry of the road
junction is known, as well as its connections between incoming and outgoing
lanes and roads. Using the location data provided by the communicating
vehicles, first, we estimate some primary parameters including the penetration
ratio of the probe vehicles, as well as the arrival rates of vehicles (equipped
and non-equipped) per lane by introducing the assignment onto the lanes.
Second, we give estimations of the queue length of the 3-lanes road, without
and with the additional information provided by the location of the
communicating vehicles in the queue. We illustrate and discuss the proposed
model with numerical simulations.
