This paper presents an overview of a National project carried out in France since 2014. The project aimed assessing the feasibility of using high-speed WIM systems for direct enforcement of overloads, and to prepare their certification. Specifications are proposed for a type-approval procedure, taking into account the requirements of the Ministry of Transport. They follow the International Recommendation R-134 of the OIML, with a few adaptations and derogations. Field tests were carried out over 3-4 years on a motorway with two WIM systems and more than 1,500 trucks and 330 vans from the traffic flow. The accuracy of these systems was assessed both by a statistical approach (COST323) based on tolerance intervals and confidence levels, and a metrological approach based on maximum permissible errors (OIML). Both WIM systems meet the COST323 accuracy class A(5) for trucks and class B(10) for vans, all with fully loaded vehicles. Therefore, the feasibility of using high-speed WIM for direct enforcement was shown. The next step will be the type-approval of the instruments. Finally, a closed test track (Transpolis, near Lyon) was proposed to carry out type-approval tests. Measurements with two instrumented vehicles were done in 2019-2020, in order to assess the maximum variations of the axle impact forces, and to compare them with the measurements on the motorway and with the tolerances of the expected accuracy classes. The closed test site is technically qualified to welcome type-approval tests of WIM systems or direct enforcement. The project paves the way for direct enforcement by WIM.