ABSTRACT
Overloaded vehicles occur less frequently in comparison to properly loaded vehicles but due to their greater potential to cause damage they significantly contribute to the distress of pavement structure. As the studies show, the phenomena of vehicles overloading intensifies when the control of traffic is poor and the average percentage of overloaded vehicles on analyzed roads varies from 6% to 23%. The main goal of the article is to assess the impact of vehicles overloading on the service period of flexible pavements. In this purpose the data from 10 weigh in motion stations on Polish national roads and motorways, which included up to 11 million records of heavy vehicles, were analyzed. Mixed axle loads in particular vehicles were transformed into number of equivalent standard axle loads and further into the load equivalency factors for particular trucks (truck factors). Each vehicle was also checked for overloading. It was revealed that average monthly truck factors are well correlated with the average monthly percentage of overloaded vehicles. This relationships were used to assess the impact of vehicle overloading on service period of flexible pavements. The approximate method of calculation of extended fatigue life of a pavement structure and its service period is presented and allows easy evaluation of the effect of minimizing of percentage of overloaded vehicles.
