15. The expert from France presented the results of testing tyres of commercial vehicles (classes C2 and C3) for the deceleration test method using the dω/dt form for measuring rolling resistance (GRB-61-09). The aim of this study was to compare the measurements obtained at a dedicated and non-dedicated rolling resistance machine. The results at the non-dedicated rolling resistance machine demonstrated a poor repeatability of the measurements, thus leaving open the question whether or not such machines are suitable for the proposed deceleration test method. GRB was of the view that further studies would be necessary and encouraged other laboratories to conduct such tests.