Proposal to amend and supersede document ECE/TRANS/GRSG/2026/16. Supplement 1 to the 01 series of amendments to UN R166 addresses vehicles of categories X and Y. Vehicles of category Y and category X without manual mode intended for on-board operation are exempted from the scope. Vehicles of category X equipped with manual mode seated in a driver’s seat must comply with general provisions. Manual operation other than seated in a driver’s seat may apply alternative provisions. The Regulation applies to vehicles of category M₁ and N₁. New definitions of “Safety Concept” are introduced. Requirements address close-proximity front and lateral field of vision from adjusted driver’s ocular points.