This paper seeks to clarify the expected approval process to be utilized by Contracting Parties concerning UN Regulation No. 131 which requires Contracting Parties applying UN R131 and UN R152 to recognise approvals to either Regulation as equally valid for vehicles of category M₂ and for those of category M₃/N₂ with a maximum weight below or equal to 8t and equipped with a hydraulic braking system.