ASEP	Informal Group on Additional Sound Emissions Provisions Last session: November 2005
ASEP II	2nd Informal Working Group on Additional Sound Emission Provisions Last session: February 2022
EFV	Informal Group on Environmentally Friendly Vehicles Last session: June 2011
GTRQRTV	Global Technical Regulation for Quiet Road Transport Vehicles Informal Group Last session: May 2018
IWG-R51/R59	Informal Working Group on UN Regulations Nos. 51 and 59 Last session: October 2014
QRTV	Informal Group on Quiet Road Transport Vehicles Last session: February 2012
R41WG	Informal Working Group on Motorcycle Noise Emissions (Regulation No. 41) Last session: June 2010
REG58-QRTV	Informal Working Group for the Development of a UN Regulation on Quiet Road Transport Vehicles Last session: February 2016
STD	Joint GRRF/GRB informal group on Special Tyre Definitions Last session: August 2009
TFRWS	Task Force on Reverse Warning Sound Issues Last session: October 2021
TYREGTR	Informal Group on the Development of a Tyre GTR Last session: September 2019