Proposal from the informal group on UN Regulation No. 55 to introduce provisions for coupling applications in multi-vehicle combinations ( e.g. rigid truck + dolly + semi-trailer) presently not addressed by the regulation.

Further refinements from the informal group on UN Regulation No. 55 to introduce provisions for modular vehicle combinations (e.g., rigid truck + semi-trailer + dolly). This proposal concerns a procedure to identify allowable combinations of performance values Dc and V for drawbar coupling equipment.

Proposal to ensure that coupling balls do not block rear lighting and/or registration plates. In line with the EU General Safety Rule, Annex IV specification for application of UN R55, couplings that might block lighting or plates must be removable, repositionable, and unlockable in order to make it easier for users to remove them or reposition them when not in use (e.g., towing a trailer.) Coupling balls that are so designed as to be unable to block lighting or plates may still incorporate locks and/or require tools to remove or reposition.