The concept of bridge weigh-in-motion (B-WIM) has been implemented for a few years now in the commercially available system SiWIM. Improvements have been undertaken during the Bridgemon project. Many of these novelties have been programmed and installed in the SiWIM and all these improvements have led to an accuracy class A(5) for gross weights on a beam-and-slab bridge. This updated system has been tested during the Summer 2015 on a culvert bridge at Senlis, on the motorway A1 north of Paris. The class C(15) has been achieved for the real traffic. This solution is of interest for concessionary motorway companies, to assess the number and frequencies heavy loaded vehicles and the induced damage on pavements and bridges.