UNECE to introduce methodology to measure particle emissions from tires

19 February 2024

Following the adoption last year of a methodology to measure the emissions from braking systems, the UNECE’s World Forum for Harmonization of Vehicle Regulations (WP.29) now developed a proposed methodology to measure emissions from tire abrasion—another significant source of non-exhaust emissions.

The Working Party on Noise and Tires, with support from the Working Party on Pollution and Energy (GRPE), has adopted a proposal to introduce two methods to measure tire abrasion under UN Regulation No. 117:

• On open roads in vehicle convoys driving 8,000 km;
• In laboratories on an abrasing rolling drum over 5,000 km.

Tire weight loss due to tire abrasion will be expressed in milligrams per kilometer per ton of load on the tire.

These measurement methods are expected to be applied in a market assessment exercise, aiming to collect abrasion data from diverse tire sizes, patterns and brands. Such data would then be used to determine tire abrasion limits to be incorporated in UN Regulation No. 117 by September 2025 for tires fitted to passenger cars (C1 tires).

Once these abrasion limits are in force, tire manufacturers will need to ensure that all the tires sold on the market are below the set limits. For those exceeding the limits, manufacturers will need to adjust their material composition or manufacturing process.

The proposal was prepared under the leadership of France and the European Commission and will become the reference methodology of the Euro 7 proposal of the European Union.

The measuring method is expected to be expanded to heavier vehicles with C2 and C3 type of tires during 2026 and 2027 to cover most road vehicle categories.

Once in force, these regulations will contribute to significantly reducing microplastic pollution. In 2016, tire abrasion was estimated to represent 78% of the 1.3 million metric tons of microplastics entering the ocean, according to UNECE.

Source: UNECE