When evaluating existing bridges, supporting structural monitoring is increasingly being used in order to obtain the stresses in the structure more realistically than purely mathematically and to calibrate the calculation model. The question of how the additional information obtained through measurements have to be taken into account within the recalculation, including its safety concept, is currently still normatively unclear. On the load side, this can be done through the modified definition of the target load level or, alternatively, through object-specific load models for loadbearing capacity and fatigue to map the actual traffic. Furthermore, on the basis of the measurement data, the necessary safety factors can be justified, also taking into account future traffic developments, while maintaining the normatively required level of reliability.