The document presents a European heavy-duty vehicle and tyre market overview and C3 test method development status. The C3 tyre market is complex and diversified, with applications including long haul, regional, on/off road, winter, and urban use. A test concept has been developed focusing on road usage with 22.5" tyres, using convoys of up to four vehicles with defined acceleration standards, road distribution of 60% motorway and 40% regional roads, and tests per axle comparing candidate tyres to reference tyres. Current activities include assessment of reference tyres strategy, temperature sensitivity evaluation, and confirmation of test parameters for heavy trucks in N₃/O₃ configuration, with tests reaching 30,000 to 45,000 kilometres.

ETRTO analysis of the European C3 tyre market segmentation, emission levels per tyre segment, and vehicle configurations. ETRTO recommends focusing on Segment A (Heavy Duty Tyres 22.5 for Long haul and regional usage), which captures approximately 71% of wear emissions. ETRTO evaluated five alternative methods to the convoy method using criteria including time to market, representativeness, regulatory suitability, and cost. ETRTO concludes the convoy method focusing on Segment A is the only feasible method given the mandated timeline, despite drawbacks including test duration and environmental impact.

Proposal to suppress the loading restriction to 85% of vehicle payload, allow several propulsion energy converters, allow mixing different transmission architectures, include circuit abrasion level measurement possibilities for snow tyres not measuring Severe Snow Tyres, and establish new circuit abrasion level limits based on 17 circuits in the 2026 Confirmation plan. ETRTO is testing acceleration correction, fully loaded vehicles, different energy converters and transmission architectures, alignment specifications for various vehicle types, and load distribution management to reduce test uncertainties and improve method efficiency. An informal document will be proposed in January 2027.

Update proposal for UN R186 to modify load distribution in para. 1.6.2 to apply only to C₁ tyres and add minimal ballast requirement for C₂ tyres, update temperature ranges in para. 1.10.4 for normal and snow tyres, and develop alignment prescriptions for C₂ tyres. The proposal describes a test concept using convoys of up to 4 vehicles with single tyres up to 3.5T GVW under controlled driving conditions to determine tyre abrasion level index. SRTT usage strategy and market assessment to be finalized following temperature testing results.

Proposal to modify the equivalence procedure for tyre test facilities to include circuits meant for severe snow tyres and snow tyres not classified as severe snow tyres, revise the selection criteria for exercise tyres to require an ALI range of at least 0.40 units with approximately even distribution and a specified ratio of normal tyres to snow tyres, and restrict equivalence of facilities designed for testing only normal tyres or specific snow tyre categories to the corresponding tyre category.

Presentation on Stage 1 test campaign results for WGWT test procedure precision. ETRTO achieved a Weighted Standard Deviation of 0.071 for Normal and 3PMSF categories, exceeding the 12% targeted KPI improvement by over 50%, demonstrating that R117 amendments to improve precision were effective. ETRTO states the KPI target is fully achieved and is not in favor of JASIC’s proposal to revise correction formula coefficients, as the 2025 dataset is not representative and such revision would deteriorate standard deviation of the 2021 Round Robin Test dataset.