This International Standard specifies the requirements for the various elements and dimensions of towing vehicles with rear-mounted coupling and of drawbar trailers, to ensure interchangeability. NOTE Annex B gives examples of different configurations of vehicle combinations; this International Standard deals only with No. B.1.1. This International Standard is applicable to road trains for commercial transport of cargo of the greatest possible variety; it does not cover dedicated or special combinations. Nor does it specify limitations of maximum gross mass and overall dimensions, which are generally laid down by legislative requirements. Vehicles whose couplings form the subject of this International Standard are not interchangeable with vehicles whose couplings are mounted forward and below (which form the subject of ISO 11407 [1]).