Nowadays, the measure and classification of vehicles in road traffic is accomplished by inductive loops placed under the pavement. These inductive loops allow monitoring vehicle passing by means of different configurations which provide us a number of data in order to control several parameters of the traffic (vehicle speed, traffic congestion and traffic accidents, between others). The major objective of this paper is to analysis an alternative to magnetic loops: the Wireless Sensor Networks. Firstly, a state of the art about road traffic control is described. Secondly, an alternative system based on Wireless Sensor Networks is analyzed. Network architecture for this WSN will be specified. It is not a trivial task because of the hard constraints of the small devices which compose the WSNs. In previous papers [1], we have proposed a methodology that facilitates the WSNs design for supporting real time applications such as traffic control applications. This design methodology has been used in order to obtain a WSN that reaches the real time requirements of a monitoring traffic application for intelligent roads. In the short term, the aim is to define a simulation model based on the designed WSN. To conclude, we have introduced a section about possible future directions in the smart roads field
