Informal Working Group: A group of experts authorized to develop proposals for consideration by WP.29 without being bound by formal UN rules of procedure.

Separate Technical Unit: Refers to the approval of a component in a larger system subject to the same regulation.

Vulnerable Road User: A person using the road who lacks the protection of an outer vehicle shell or equivalent restraint system, and who is therefore at disproportionate risk of serious injury or death in a collision involving motorized traffic.