Working Party on Lighting and Light-signalling Equipment (cf French: Groupe de Rapporteurs sur l’Eclairage)
GRPE
Working Party on Pollution and Energy (cf French: Groupe de Rapporteurs sur la Pollution et l’Energie)
IWG
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.