Probabilistic models for Italian road traffic with gross vehicle weight limitations based on weigh-in-motion data

Abstract

Traffic load models provided by standard regulations play a major role in both design and management of road infrastructure. Considering the persistent change in the traffic load characteristics, a proper validation of code-based models with real traffic data becomes necessary, especially for their implementation in safety checks and monitoring of existing bridges. In this context, this study presents a comparative assessment of present Italian road traffic obtained from two weigh-in-motion stations located along European route E45 close to Naples, Italy, with existing European traffic. The traffic data was filtered to remove erroneous data and then classified based on the number and spacing of vehicle axles. Suitable unimodal and multimodal probabilistic models were then identified for major vehicle parameters such as gross vehicle weight, vehicle speed, axle weight, axle distance and relative axle weight. The paper ends with a preliminary comparison between measured traffic loads and existing traffic load models from bridge design standards. The results clearly indicate a significant variation in the available traffic load models with the present-day traffic. This comprehensive assessment considering different types of vehicles and traffic flow characteristics lay the basis for a future study to investigate the distribution of real traffic effects and its variation with respect to code-based traffic models.