Proposal to update and clarify the regulation. The proposal refines definitions, removes the “AWD” abbeviation for “audible warning device” to avoid confusion with its more common use for “all wheel drive”, adds T category agricultural vehicles to the scope, modifies some administrative communications, and proposes three-direction acoustic measurements.

In response to concerns that approval agencies may not grant manufacturers the additional 1dB for L(wot) on conformity of production tests as changes had been made to Annex 6 of R41-04, GRB issued an interpretation recorded in the report of its 56th session. The proposal formalizes the interpretation as an explicit provision of the regulation.