Document Title UN R28: Soft horns
Reference Number GRBP-82-05
Date
26 Aug 2025
Summary A proposal to meet the objective to reduce noise pollution (particularly in towns) and to be able to warn pedestrians, cyclists and others of the vehicle's arrival with the least possible discomfort.
Source(s) France
Rulemaking Area(s) UN R28 Audible Warning Devices
Meeting(s)
Downloads
UNECE server .pdf format .pptx format
GAR server .pdf format .pptx format
Excerpts from session reports related to this document
GRBP | Session 82 | 3-5 Sep 2025

27. The Chair presented a revised list of priorities (GRBP-82-36) and invited experts to provide comments with the aim to update the document accordingly, for inclusion into the 2026 Programme of Work of WP.29.

28. As a possible new topic, the expert from France proposed to address audible warning in the event of failure of the Rechargeable Electrical Energy Storage System (REESS) for vehicles of O categories, as envisaged in UN Regulation No. 100 (GRBP-82-04). Before taking a decision, GRBP agreed to ask the Working Party on Passive Safety (GRSP) and WP.29 for guidance.

29. For M and N categories of vehicles, the expert from France proposed to complement UN Regulation No. 28 «Audible warning devices» with a paragraph to define the approval criteria for the so-called “soft horn”, with the aim to reduce noise pollution and to warn pedestrians, cyclists and other road users about the vehicle arrival with a minimum discomfort (GRBP-82-05). GRBP experts expressed various views on this idea. The expert from France volunteered to collect the opinions and to prepare a new informal document for the next session.