Some surveys in order to static traffic light coordination

The traffic light coordination is often considered as a measure to improve traffic speed reducing car emission per meter. Although the dynamic approach has been widely developed in theory and application, static approach can be still useful in many design problems. Often design is made by static approaches and is also verified with dynamic models. The static approach study, in this paper, starts from flow profiles of vehicle platoons departing from a traffic light. Several past studies have concerned on the definition of flow profiles and in this paper it considers the collecting data modeling using the approach of cyclic flow profiles (TRANSYT TRRL) who gives the arrival distribution of flow platoons as a function of the distance from the first intersection through a recurrent computing. So it can know the car number in late for the green phase at the second light and then decide to increase the second green time according to the access waiting time or, conversely, reduce the green time at the first light accepting a queue. The last results obtained seem, in part, to confirm those by last surveys already performed. These results give basically always and still different from the values of the two coefficients (dispersion and transit time) registered in the U.S. The estimated values can be used as is, however, if it is essential a level of approximation in order to the model very detailed then, as usual, is best to check the model coefficients with some localized surveys and measures. The experimentation showed the validity of static approach and also some its limit discussed in the paper.