UN R48 baseline text for a 10 series of amendments proposes uniform provisions for vehicle lighting and light-signalling device installation approval. The document consolidates modifications agreed at working group session through dated amendment documents and resolutions. Pending issues include determining “[any] subsequent series” terminology for frozen regulations, renumbering and cross-checking paragraphs, addressing apparent surface visibility, improving daytime running lamp visibility against stop lamps, resolving “prohibited if not allowed” language, and numbering all figures with titles. Editorial polishing includes standardizing hyphenated terminology (“driving-beam,” “passing-beam,” “retro-reflector,” “direction-indicator lamp”), applying consistent UN Regulation references, replacing “communication sheet” with “communication form,” assigning table and figure numbers consistent with similar regulations, and correcting percentage notation to “per cent.”

GTB proposes simplifying UN R48 by developing a single CAD-based method to determine apparent surface at early design stages. The proposal deletes the “light-emitting surface” definition and establishes “apparent surface” as the orthogonal projection of visible light-emitting surfaces in a specified observation direction. Amendments include revised definitions for lens, textured outer lens, illuminating surface, and apparent surface, with modified requirements for single lamps with multiple distinct parts. Distance requirements between adjacent parts are adjusted to 75mm or 200mm depending on lamp type.

The agenda includes corrections to UN R150-01, baseline documents for UN R53, R74, R86, and R48, simplification of paragraphs 6.×.4 and 6.×.5, transitional provisions, harmonisation of requirements, apparent surface considerations, and direction indicator visibility improvements. The next meetings are scheduled for June and December 2026, with a potential September 2026 session in Tokyo.

This document addresses rear direction-indicator lamps mounted at low positions on vehicles. Republic of Korea reports increased public petitions and media articles regarding visibility and recognition concerns, particularly in congested traffic and for vehicles with higher driver seating positions like SUVs. UN Regulation No. 48 specifies direction-indicator lamp height requirements: not less than 350 mm and not more than 1,500 mm, or up to 2,100 mm under certain structural conditions. The presentation seeks feedback on similar issues from other countries and manufacturers.

The HWT analyzed literature and expert knowledge to identify glare causes, performance negative effects, and improvable requirements for ADB/AFS systems. Key issues include wet road conditions, external objects obstructing sensors, soiled headlamps, and insufficient dynamic masking accuracy. Recommendations include improving headlamp cleaning enforcement, enhancing vehicle detection requirements, introducing motorway ADB usage, implementing adaptive cut-off lines, and providing manual override instructions.

A literature review on direction indicator visibility presents research on vehicle lighting design, visibility, and signalling. Sources include studies on overlapping and interlocking of lights, and dynamic evaluation of automobile rear lighting configurations.

The document analyzes separating direction indicators and stop lamps. It examines how drivers recognize lighting functions through visual perception and notes that irregular lamp shapes increase reaction time. The document states that “apparent surface”, currently defined only through manufacturer drawings, lacks perceptual grounding because it ignores luminance distribution and edge contrast. It recommends minimum lamp sizes and distances based on visual acuity, minimum luminance requirements, and a 3:1 luminance contrast between functions when spatially merged in one lamp.

OICA presents research findings on direction indicator perceptibility when stop lamps activate simultaneously. Key findings indicate that spatial separation between functions, increased direction indicator intensity, and relative signal dominance improve perception. Research shows stop lamp luminance can reduce direction indicator recognition, particularly in near-field viewing. OICA concludes that minimum size requirements proposed in the German proposal exceed available evidence and may create unintended consequences without demonstrated safety benefits.

CLIV is developing a new UN Regulation for vehicle categories M1, M2, M3, and N1 in Phase 2. The draft regulation requires visual and audible external warnings upon detection of a child left in a vehicle. Visual warnings use direction indicator lamps flashing in SOS morse code pattern for at least 15 seconds, then off for no more than 30 seconds, repeating for at least 10 minutes. Audible warnings must exceed 60dB(A) following the same timing pattern. The IWG requests guidance on potential amendments to UN R48, UN R28, and UN R165.

SLR-76 session documents are available on the SLR website. Actions include: correcting errors in UN R150 for submission to GRE-94; preparing Stage 2/Step 2 baseline documents for UN R48, R53, R74, and R86; finalizing simplification of paragraphs 6.×.4 and 6.×.5; discussing apparent surface methodology; approving technological neutrality amendments to UN R48 and R149; collecting literature on rear direction indicator visibility; and reviewing harmonization requirements. SLR-77 meeting scheduled April 15-17, 2026 in Brussels.

Proposal to clarify manufacturer logo requirements across several paragraphs: confirming that non-illuminated graphic marks are not considered logos (para. 2.1.7.); permitting vehicle manufacturers to keep the inner portion of a front position lamp active when an AFS headlamp substitutes the outer portion (para. 5.12.1.4.); improving logo language for Light Signalling Devices approved to UN R148 (para. 5.30.1.); and clarifying that Road Illumination Devices approved to UN R149 shall not include a manufacturer logo (para. 5.30.2.).