THE FIRST WIM SYSTEM DESIGNED IN POLAND

In last years the traffic on Polish roads rapidly increases, more and more of shipment is transported by lorries. The infrastructure and condition of Polish roads isn't god, than appears necessity to protect them. One of possibiLities is to control the vehicle overloading. Up to now six weighing sites are installed in Poland. The sites consists of static scaLe and preseLection systems for each direction. UnfortunateLy the preseLection systems equipped with capacitive sensors are damage after a few month. Than the first Weighing in Motion - WIM preselection system, fully designed, programmed and assembled in Poland, has been put into service in ApriL 2001. The system operates in standard configuration, i.e. it is equipped with two strip piezoelectric sensors and one inductive loop located between them. Each axle is weighed twice due to the empLoyment of two WIM sensors. The arithmetic mean vaLue of both results is assumed as the final axle load. The measuring range of the system Lies between few hundreds of kilograms to 20 tons for the vehicle velocity included in the range 25 - lOO kmlh. The described system allows vehicle detection in the measurement zone as well as estimation of a singLe axle and the whoLe vehicle loads, measurement of the vehicle velocity, number of axles, the distance between successive axles. Trailer detection is also possible, based on the vehicle magnetic profile, registered with the inductive loop. The statisticaL characteristics describing the traffic observed on the chosen road section are presented in the paper, specially the distribution of the vehicles number in the course of a day and night as well as in the course of a week. The effectiveness of detection of permissible parameters, such as velocity and axles load, is also estimated.