WIM data makes it possible to assess precisely the consequences of changes in the regulations on the weight and dimensions of the trucks in the impact on infrastructures. This is the case for impact on pavement (changes in the fatigue and rutting), on the compliance with geometrical constraints (geometry of the road and ability to drive on the existing infrastructure) and on bridge loading. We intend to present in this paper several studies on bridge loading based on WIM data and that have been conducted recently in France. In a first study, the impact of the increase of the limit of 40t for GVW for 5 axle-trucks to 44t has been investigated. It has been shown that a decrease in lifetime of the structures should be expected (decrease by approximately 10%). Another study has studied the effect of the changes in traffic between 1989 (when the European design codes for bridges have been written) and 2010. These changes have been shown with use of WIM data from 1989 and 2010: the traffic recorded in 2010 has effects beneath those induced by Load Model 1 of Eurocode 1 for bridges with spans higher than 20m, but the safety margin is reduced.