scope:

This International Standard lays down the dimensions necessaryfor the compatibility of mechanical coupling devices between lighttrailers or caravans and towing vehicles, when the latter arefitted with a coupling ball. The clearance space around thecoupling ball is intended to allow coupling and decoupling of towedvehicles, as well as safe operation during coupling and uncouplingof mechanical devices. This International Standard applies tocoupling balls designed to couple caravans and light trailers ofcategories O1 and O2 1) to vehicles of categories M or N. It doesnot necessarily apply to special trailers drawn by specialvehicles.