39. The expert from the Task Force on Autonomous Vehicle Signalling Requirements (TF AVSR) reported on their progress (GRE-84-19). He also mentioned a recent EC study on the effects of automation on road user behaviour and performance. GRE noted that a policy decision on the signalling requirements of autonomous vehicles fell in the scope of the Working Party on Automated/Autonomous and Connected Vehicles (GRVA) and its Informal Working Group on Functional Requirements of Automated/Autonomous Vehicles (IWG FRAV). GRE invited its Chair to contact the GRVA and IWG FRAV Chairs and to seek guidance on light-signalling requirements for autonomous vehicles. GRE agreed that the activities of TF AVSR would be put on hold until such guidance was received.