  We present in this paper a method to estimate urban traffic state with
communicating vehicles. Vehicles moving on the links of the urban road network
form queues at the traffic lights. We assume that a proportion of vehicles are
equipped with localization and communication capabilities, and name them probe
vehicles. First, we propose a method for the estimation of the penetration
ratio of probe vehicles, as well as the vehicles arrival rate on a link.
Moreover, we show that turn ratios at each junction can be estimated. Second,
assuming that the turn ratios at each junction are given, we propose an
estimation of the queue lengths on a 2-lanes link, by extending a 1-lane
existing method. Our extension introduces vehicles assignment onto the lanes.
Third, based on this approach, we propose optimal control laws for the traffic
light and for the assignment of the arriving vehicles onto the lane queues.
Finally, numerical simulations are conducted with Veins framework that
bi-directionally couples microscopic road traffic and communication simulators.
We illustrate and discuss our propositions with the simulation results.
