TIRE & ROAD WEAR PARTICLES

USTMA POSITION ON TIRE AND ROAD WEAR PARTICLES (TRWP)

USTMA members continually look for new ways to improve both their products and operations and their understanding of the impact of tires on the environment. The World Business Council for Sustainable Development’s Tire Industry Project (TIP) and the European Tyre & Rubber Manufacturers’ Association (ETRMA) have performed studies to assess the fate and transport of tire and road wear particles (TRWP). While the research conducted to date demonstrates TRWP do not present a significant risk to humans and the environment, USTMA supports additional and ongoing research that considers the latest science and most comprehensive methodologies.

FAQS ON TRWP

Why do tires produce particles?

Tires are one of the most important safety components of a car. They support the vehicle’s weight, absorb impact, withstand multiple weather conditions and are a car’s only connection to the road. The grip between a tire and the road surface is essential to tire safety and performance. This critical grip leads to abrasion of both tire and road surfaces, producing TRWP, a mixture of tire tread and road pavement material. Since 2005, our members have supported peer-reviewed scientific studies related to TRWP conducted by the Tire Industry Project (TIP). To date, these studies have found that TRWP do not present a significant impact to human health and the environment; however, TIP continues its research to improve scientific understanding of potential impacts. 

What factors impact the production of TRWP?

Many factors impact tire wear including tire design; vehicle characteristics (weight, distribution of load, location of driving wheels and suspension types); road surface (material, runoff design, roughness); weather (humid or dry, hot or cold); road topology (hilly or flat, winding or straight); and driving behavior (aggressive or smooth driving, high or moderate speed, respecting the correct inflation pressure, braking). As a result, there is no one-size-fits-all solution to reduce tire wear and the generation of TRWP. Rather, effective reduction of TRWP will require a multi-faceted approach, and effective strategies could include reducing the generation of particles from tires through automotive and infrastructure innovations and ensuring proper tire inflation.

What can be done to reduce TRWP in the environment?

The tire manufacturing industry is science-driven industry and committed to safety and sustainability, as evidenced by the tens of millions of dollars invested in peer-reviewed research with the World Business Council for Sustainable Development’s Tire Industry Project. The focus of our research is to assess the impact of tire materials on the environment, wildlife, and human health, including tire and road wear particles (TRWP).

Incorporating sustainable infrastructure in roadway development can provide long-term solutions. Rebuilding America’s roads should be done with investments in technologies that increase driver safety and reduce environmental impacts, including roadway runoff. USTMA is encouraged by the documented benefits of rubber-modified asphalt and bioretention technologies, such as stormwater infiltration galleries and bioswales. 

A 2006 study, conducted by the Arizona Department of Transportation, found that rubber-modified asphalt can reduce tire wear by up to 50%. CalRecycle research found that stormwater infiltration galleries made with tire-derived aggregate reduce stormwater pollutants such as zinc and iron by over 80% and research by the University of Minnesota found stormwater galleries with tire chips reduce pollutants in stormwater runoff by over 60%.

To learn more about mitigation options for TRWP please see the summary note from the OECD Workshop on Microplastics from Tyre Wear: Knowledge, Mitigation Measures, and Policy Options. 

Motorists can also help reduce the amount of TRWP produced by maintaining proper tire pressure. Under-inflated tires can impact tire safety, performance, and tread life. USTMA recommends that consumers check their tire pressure at least monthly to maximize the performance and life of the tire.

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