Speaker Interviews

Discover more about the topics and technologies to be discussed at Tire Technology Virtual 'Live', via a series of exclusive interviews with a selection of our expert speakers!

Dominique Cettour-Janet - Michelin senior fellow for tire performance evaluation and tire physics - ETRMA-ETRTO

What is your presentation about?

Tire and road wear particles (TRWP) are generated by the friction between tires and the road surface. This friction is essential to ensure road safety as it is the friction that is holding the vehicle on the road. As such, to guarantee this road safety and given current scientific knowledge and available technologies, a certain amount of TRWP may always be produced. The European tire industry is committed to developing a test method that will measure the abraded mass per unit distance from passenger car tires. This talk will provide extensive information about the tire abrasion test being developed by the European tire industry.

Why are tire and road wear particles a concern?

Estimations through traffic data or tire yearly sales lead to a total annual release of about 500,000 metric tons of tire rubber due to wear in the EU.1 In the early 2000s, several tire makers began asking questions about the fate and potential human health and environmental impacts of the particles generated as tires move over road surfaces. There was little existing data to help answer these questions at that time. In 2005, 11 tire manufacturers established the Tire Industry Project (TIP) to initiate research into the particles generated by tires, and to develop an understanding of other potential human health and environmental impacts of tires throughout their lifecycle.

Airborne TRWP were found to make only minor contributions to the total PM collected in the PM10 and PM2.5 range (on average less than 1%). TRWP presents low potential for adverse cardiopulmonary health effects based on toxicity. Studies looking for acute or chronic aquatic toxicity indicated a low potential for risk from exposure to TRWP in aquatic ecosystems for all tested species. Only last December, scientists on the northwest coast of the United States published a study making a link between a degradation product of an anti-oxidant present in all tires (6PPD-quinone) and the mortality of a species of salmon (coho salmon). The tire industry takes this study very seriously and is strongly committed to understanding the stakes and consequences.

What can be done to reduce these particles?

TRWP release is the direct consequence of friction between the road and the tire, which enables vehicle control and ensures driving safety. It is impossible to completely eliminate it as it is the counterpart of adherence force building, which slowly damages the tread material. This phenomenon also occurs with your shoe soles when you are walking. Improved tire design can only reduce this release. Other levers can be found in driver education for a softer driving style, which is also in line with fuel consumption reduction, or in road designing, in solutions to collect these particles in road runoff or sweeping streets and roads. In this regard, in 2018 ETRMA launched the European TRWP Platform, a multi-stakeholder proactive approach to explore a balanced and holistic method to address and understand TRWP issues and to co-design mitigation actions, which can be found in the Way Forward Report.

How does the tire abrasion test work?

The European tire industry is working through this first phase to develop an on-vehicle method. Here, the vehicle is used as a machine to operate tires and measure their abrasion. The metric will be a mean value of tire mass loss rates from the left and right positions on the drive axle. This method should be fair when ranking tires and is built to match real European driving conditions. To be able to extract the impact of the tire from all the other parameters that influence this abrasion rate, we need to specify them, for instance by selecting the route and the driving style (speed and acceleration distributions), and refer always to the same reference tire, to mitigate outside temperature variations among other factors.

How will the tire abrasion test help to reduce particles?

This method for assessing tire abrasion performance will be shared with the European Commission to support future regulatory decisions about the relevant policy options.

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