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.

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.

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.

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.

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.

Baseline document for amending UN R74 (based on WP.29/2024/91, SLR-71-07, SLR-71-7, SLR-66-01, and SLR-73-07). Key changes include: simplifying definitions; using “type-approved” and “type-approval” with hyphens per UN R48; replacing “vehicle type (moped)” with “type of vehicles of category L₁”; adding hyphenation to “direction-indicator lamp”; deleting “above” from paragraph references; clarifying UN R48 series; removing “to this Regulation” after Annex references; applying scientific notation for lumens; including electric vehicles; revising individual and general provisions; correcting signal lamp category errors; and using category symbols instead of lamp function names.

Draft amendments to UN R53 (based on SLR-71-07, SLR-71-7, SLR-66-01, SLR-73-07, SLR-75-05, and WP.29/2024/30) updates the baseline document for the 05 series of amendments. Key changes include: simplification of definitions and general specifications; consolidation of individual specifications; addition of EV inclusion and failure provisions; editorial harmonization with UN R48 baseline regarding hyphenation, terminology, and formatting; replacement of “visual failure tell-tale” with “tell-tale indicating failure” and “rear-end collision alert signal” with RECAS; standardization of vehicle category references; adoption of scientific notation with lumens; simplification of paragraphs 6.4 and 6; and revision of the transitional provisions.

Based on SLR-76-03-Rev1 for R48 and tentatively applying WP.29/2024/76, IMMA presents transitional provisions for UN R53. The document outlines provisions applicable to all amendment series, including that Contracting Parties may grant type-approvals according to any preceding series and shall continue granting extensions of existing approvals. For the 05 series of amendments, specific dates establish when Contracting Parties shall accept or refuse type-approvals, with exceptions for equipment, parts, and unaffected vehicle systems.

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.

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 document addresses simplification of the definition of “apparent surface” and single lamp distance requirements in UN R48. It presents a new CAD-based concept defining apparent surface using light emitting surface with clear outer lens disregarded. The document notes that current regulation allows multiple ways to define apparent surface resulting in different distances, with existing approvals having distances significantly larger than 75mm between distinct parts without known safety issues. GTB agrees on simplifying the apparent surface definition to describe function contours as seen by road users, while acknowledging this should not restrict possible designs. The document references a 1999 INF Milano study concluding symmetric appearance is relevant for vehicle identification and larger distances are acceptable for symmetric compared to asymmetric constellations.

The document provides follow-up information from the SLR 77th session. SLR-77-06/Rev.1 corrects errors and omissions in Reg. 150 and will supersede GRE-94-02, potentially merged with the proposal deleting UI in R150-01 for WP.29 submission in November 2026. Four baseline documents for Stage 2/Step 2 work (SLR-77-08/Rev.1, SLR-77-09, SLR-77-10, SLR-77-07 for Regs. 48, 53, 74, 86 respectively) will be submitted to GRE-94 with presentation slides. SLR agreed to keep Par. 6.21 on conspicuity marking and to renumber paragraphs 5.5 to 5.36. Old transitional provisions are documented separately. Apparent surface definition will replace light-emitting surface. Direction indicator visibility requires further study. Harmonisation text prohibits non-mentioned lamps unless compliant with national requirements. Eleven informal documents will be submitted to GRE-94.

Proposal to amend, restructure, and clarify UN R86:

• Update the regulation title and scope to reference vehicles of category T, R, S, agricultural and forestry NRMM vehicles regarding installation of lighting and light-signalling devices
• Restructure and reorganize para. 2 (Definitions) by consolidating lamp definitions, deleting outdated definitions, and reorganizing vehicle-related and lamp-related definitions into separate sections
• Revise para. 3 (Application for approval) to clarify submission requirements and add reference to Annex 1 documentation
• Amend para. 4 (Approval) to reference Schedule 4 of the 1958 Agreement and update approval mark procedures in Annex 2
• Restructure para. 5 (General specifications) by reorganizing and renumbering provisions relating to lamp position (para. 5.5.), geometric visibility (para. 5.6.), single lamps (para. 5.9.2.), tell-tale requirements (para. 5.14.), concealable lamps (para. 5.15.), and lamps of variable position (para. 5.17.), and revise provisions regarding electrical connections for front and rear position lamps, driving-beam and passing-beam headlamps, and daytime running lamps
• Restructure and revise para. 6 (Individual specifications) by introducing para. 6.0. as a general introductory provision, renaming driving-beam and passing-beam headlamps throughout, reorganizing direction-indicator lamp arrangements as A, B, C, D, E with detailed geometric visibility specifications in para. 6.5.5., revising stop lamp position and geometric visibility requirements in para. 6.7., restructuring front and rear position lamp requirements, revising rear fog lamp electrical connections, clarifying parking lamp requirements, restructuring rear and front retro-reflector specifications to include separate sections on electrical connections, tell-tale, and other requirements, reorganizing side-marker lamp provisions, clarifying conspicuity marking requirements, revising SMV rear marking plate specifications, restructuring exterior courtesy lamp and manoeuvring lamp requirements, and updating all light colour specifications
• Amend para. 8 (Conformity of production) to include reference to the Agreement Schedule 1 and clarify the conformity requirements
• Clarify para. 10 (Production definitively discontinued) regarding notification requirements
• Revise para. 12 (Transitional provisions) to replace existing series-specific provisions with general transitional provisions applicable to all series of amendments and add new transitional provisions for the 04 series of amendments with dates specified as 1 September 20xx (pending confirmation)
• Update Annex 1 (Communication) to reference the 04 series of amendments in the approval mark examples and add informative tables (TableA4-1 and TableA4-2) in Annex 4 (previously Annex 3) summarizing lighting and light-signalling installation rules for tractors/agricultural and forestry NRMM (vehicles of category T) and vehicles of categories R and S
• Revise Annex 2 (Examples of arrangements of approval marks) to reference the 04 series of amendments and update marking examples
• Delete Annex 3 (The relevant parts of Annex 3 to UN Regulation No. 48 apply) and replace with visibility zones diagrams in new Annex 3
• Reorganize former Annex 5 (Direction-indicator lamps – Geometric visibility) and incorporate into new Annex 4 as summary tables with footnotes explaining special conditions
• Update Annex 5 (Signalling panels and signalling foils) to clarify dimensions, arrangement, number and reflecting surface requirements with references to updated figures and table

This document proposes draft provisions for a 05 series, updating the previous baseline (SLR-71-07). Key changes include simplification of definitions by referencing UN R48 where applicable; consolidation of geometric visibility requirements with uniform formatting; incorporation of electric vehicle (EV) provisions; inclusion of rear-end collision alert signal (RECAS); replacement of legacy terminology with hyphenated forms (e.g., “direction-indicator lamp,” “type-approved”); use of scientific notation for luminous intensity values; and reduction of transitional provisions to retain only the 05 series requirements. Annex 3 has been reserved and deleted. The regulation applies to the installation of lighting and light-signalling devices on motorcycles and prescribes mandatory and optional devices with specifications for position, geometric visibility, orientation, electrical connections, and tell-tales. Transitional provision dates remain undecided.

The document considers options for the Communication form of UN R53 regarding whether to include the UN R48 series number. Option 1 retains the current form without the series number. Option 2 adopts the current Baseline document style. Option 3 adds an area in the comment section. Option 4 invites other ideas. Feedback is requested on which option should be adopted.

Amend para. 5.1.2. to change the number of samples from ten to eight, modify para. 5.1.3.1. to reduce samples from ten to eight and divide the other six samples into three groups instead of four by deleting the fourth group colour-fastness test requirement, add para. 5.1.7. specifying the chronological order of tests in tables for Classes IA, IB, IIIA, IIIB and Class IVA, and amend para. 3.5.3.1. to add provisions for verification of stability in time of optical properties and colour of retro-reflecting optical units of advance warning triangles in use and withdrawal of approval for systematic deficiencies.

Proposal to amend para. 3.5.3.1. to delete reference to colour verification of retro-reflecting optical units, amend para. 5.1.2. to reduce required samples from ten to eight, amend para. 5.1.3.1. to reduce samples from ten to eight and divide remaining six samples into three groups of two, insert para. 5.1.3.1.1. specifying Classes IA, IB, IIIA and IIIB, amend para. 5.1.7. to delete sample columns i and j from Tables 4 and 5 and delete the weathering resistance test row, and amend reference to Part 4 of Annex 6 to Part 5 of Annex 6 in both tables.

Proposal to amend UN R86 on approval markings and testing requirements:

• Delete provisions regarding the Unique Identifier and conditional use of conventional type approval markings from the Introduction
• Amend para. 3.3.1.1. to delete reference to the Unique Identifier
• Amend para. 3.3.1.3. regarding approval marking proportions
• Add new para. 3.3.2.5. requiring a vertical downward arrow for devices with reduced light distribution
• Delete para. 3.3.3. on Unique Identifier entirely
• Renumber para. 3.3.4. as 3.3.3.
• Renumber para. 3.3.5. as 3.3.4. and amend to delete reference to Unique Identifier
• Renumber para. 3.3.6. as 3.3.5. and amend to delete reference to Unique Identifier
• Amend para. 5.1. to include Classes IIIA, IIIB and IVA
• Amend para. 5.1.3.1. regarding heat resistance testing and divide samples into groups for testing Class IA, Class IB, Class IIIA and Class IIIB
• Add new para. 5.1.3.1.2. for Class IVA testing
• Amend para. 5.1.7. to create separate Tables 4 and 5 for chronological order of tests for Classes IA, IB, IIIA, IIIB and Class IVA respectively
• Amend para. 5.2.3.3. to reference Part 1 of Annex 6 and paragraphs 5.2.5. and 5.2.6.
• Amend para. 5.2.5.1.1. regarding coefficient of retro-reflection measurement
• Delete para. 5.2.5.2.1. entirely
• Amend para. 5.2.6.3. to include colour requirements and insert Table 8
• Amend para. 5.2.6.4. regarding luminance factor
• Renumber Tables 8, 9 and 10 as Tables 9, 10 and 11
• Amend para. 5.3.5.2.2. to reference Table 11
• Amend Annex 1 Item 5. and delete reference to Unique Identifier in Item 10
• Amend Annex 5 para. 8.1.4. to correct cross-reference to para. 5.3.4.2.1.
• Amend Annex 6 Part 2 para. 1.3.2. to reference para. 5.2.5.1.
• Amend Annex 6 Part 2 para. 2.1.3. to correct paragraph references
• Amend Annex 6 Part 4 para. 4.2. to reference Table 6 only
• Insert new Part 7 in Annex 6 on colour-fastness for Classes IA, IB, IIIA, IIIB and IVA
• Amend Figure A10-I to clarify marking arrangement rules and delete the diametrically opposite requirement

The agenda addresses correction of errors and omissions in UN Regulation 150-01, including a consolidated proposal merging GRE-92-18, GRE-94-02/Rev.1, GRE-94-11, and GRE-94-24, and a decision on addition of Part 7 on Colour-fastness to Annex 6. Baseline documents for UN Regulations Nos. 48, 53, 74, and 86 will be reviewed, along with transitional provisions. The group will consider visibility of direction indicators and Korean concerns regarding rear direction indicator lamp height. The 79th meeting is scheduled for Tokyo in September 2026.

This baseline draft for UN R48 (10 series of amendments) establishes uniform provisions for vehicle lighting and light-signalling device installation. The document reflects all modifications agreed at GRE-94 and incorporates an updated proposal from IEC regarding technological neutrality for LS devices. Key additions include provisions for work lamps to be included after formal WP.29 adoption in June 2026, updated tables for positioning and geometric visibility angles (Annexes 18–19), and revised terminology replacing “dipped-beam/main-beam” with “passing-beam/driving-beam” throughout. Open points address apparent surface visibility against stop lamps and consistency with IWVTA transitional provisions, with transitional provisions for the 10 series specifying acceptance dates and phase-in periods to be finalized.

The 79th SLR Informal Working Group Meeting will be held 7–11 September 2026 at AP Ichigaya, 8th Floor, AP Ichigaya, Ichigaya Osato Building, 1–10 Gobancho, Chiyoda-ku, Tokyo 102–0076, Japan. A reception is scheduled for 9 September 2026 at 18:00–20:00. The meeting includes sessions on Task Force on Glare Prevention and Task Force on Lamps Under Parked Conditions and Task Force on Autonomous Vehicle Signalling Requirements, though it has not yet been decided whether the latter two task forces will be held during the Tokyo meetings. Participants should complete the registration form.