Proposal to amend UN R158 to include category O vehicles (trailers) within the scope of regulations for devices enabling driver awareness of vulnerable road users during reversing. The amendment aims to reduce safety risks to vulnerable road users when category O vehicles reverse. Amendments modify title, paragraphs 1.1, 1.2, 1.4, 12.3, 12.4, and Annex 4, and introduce transitional provisions starting from September 2028. Justification includes casualty data showing seven fatalities and 15 serious injuries over 10 years from vehicles towing trailers reversing into vulnerable road users, plus a coroner’s recommendation for reversing cameras on all vehicles.