this paper presents the data analysis obtained from Weight-In-Motion (Piezoelectric) measuring device. Data were collected in the six-month period. Statistical analysis showed that the vehicle loads of present Latvian highway have the greater number of heavy weight vehicle and existence of a very heavy vehicle with a total weight more than 120t. Processed data of the vehicle gross and axle weight distribution as well as traffic intensities are remarkably different from the prototype data in current design codes. Vehicle’s time and space distribution also shows the distinction from existing Latvian and European design experience. To develop the accurate methodology for new and existing bridge assessment it is great significance to research bridge design loads to evaluate current and future live load evolution, and it can be done assuming WIM data.