There is a 13-30% reduction in tire roadwear particles (TRWP) for every 10 km/hr speed reduction
5.9 million tonnes of tire roadwear particle emissions are generated globally
One of the biggest challenges facing tire manufacturers is the sustainability issue of tire roadwear particles (TRWP), a subset of microplastics. There are currently no regulations regarding TRWP, but Euro 7 will have new standards that will regulate TRWP based on the weight generated per kilometre per ton of load. This report examines the relationship between the size of the TRWP, the particle size distribution and tire materials, tire construction, road conditions, road type and other considerations.
With rising pressure to minimise tire particulate emissions, this expert study examines the technical and regulatory challenges facing tire makers and the steps they are taking to combat TRWP. In particular, it explores the long-term impacts of new tire wear testing obligations contained in the Euro 7 standard, and US legislation restricting 6PPD. Smithers analysis explores the tire material sets and construction innovations that can be used to improve tread durability, while maintaining performance and managing the transition to more sustainable transportation.
Key questions:
What steps are tire manufacturers taking to improve wear and reduce the environmental burden of TRWP?
What role do automakers and government play in developing an overall solution?
What are the technical challenges of mitigating tire wear particles under proposed regulations?
What are the key opportunities in sustainable transportation?
This report benefits:
Tire makers and producers of tire materials
Equipment suppliers to the tire industry
Participants in the tire markets value chain
Table of Contents
Executive Summary
Size of the problem
Key drivers for regulating TRWP
Data gaps
Key issues and challenges to address
Suggestions on approaching the problem - Prevention to mitigation
Introduction and methodology
Report scope
Report objective
Methodology
List of definitions
Abbreviations and glossary of terms
Introduction to tire wear particles and the regulatory landscape
Size of the problem
TRWP as a microplastic
Mechanisms of tire wear and effect on TRWP
Size distribution of TRWP
Effect of non-tire variables on the generation of TRWP
Pavement
Driver behavior
Vehicle speed
Vehicle load
Ambient temperature and humidity
Traffic patterns
Relationship between 6PPD and TRWP
Health effects of TRWP
Plant/animal
Human
Technical challenges of mitigating tire wear particles under Euro 7 and US regulations
Proposed regulations TRWP
Proposed regulations 6PPD
Data gaps
Testing issues for TRWP
Distinguishing TRWP from other materials
Markers for TRWP
Testing protocols
Substituting for environmentally
Unfriendly materials
Impact of materials on tire wear particles
Fillers
Elastomers
Antioxidants and antiozonants
Curatives
Plasticizers (both resins and process oils)
Substitution of more environmentally friendly materials to reduce toxicity of TRWP
The influence of tire design and vehicle type of reducing tire wear particles
Effect of studded tires
Effect of tread pattern on wear
TPMS and self-inflating tires
New generation wide based tires
Effect of EVs on tire wear
Effect of self-driving vehicles on tire wear
Modelling of tire wear
Opportunities for more sustainable transportation
Importance of Life Cyle Analysis to the question of sustainability
Techniques for the management/mitigation of TRWP
Importance of the involvement of the tire industry, government and academia to sustainable transportation
Example of a regulatory action in progress - 6PPD and its relationship to TRWP
Suggestions on how the tire industry, government and academia can work together more productively
Potential for future regulations
Ongoing work by the tire industry in sustainable transportation
Tables
Classes of chemicals found in TRWP or TRWP leachate
TRWP contributions to microplastics by country
Reported LC50 of 6PPDQ to various salmonoid species
Relationship between vehicle speed and generation of TRWP
Comparison of Tire-Roadwear Particles, Tire Wear Particles, and Road Particles
Contribution of TRWP to microplastics by country
TRWP emission factors for different experimental conditions
Markers for TRWP
Chemicals found in TRWP or TRWP leachate
Potential substitutes for environmentally unfriendly materials
Comparison of truck tire wear - Silpara SMC vs conventional truck tread
Effect of silica level on TRWP generation
Effect of silica level on TRWP size
Use of hydrocarbon resins to improve wear - Formula
Use of hydrocarbon resins to improve wear - Results
Glass transition temperatures of process oils
Use of E2C to improve wear
Effect of tire type on TRWP
Impact categories for LCAs
Overall conclusions from tire LCA to 2021
Figures
6PPD and 6PPDQ in the environment
Formation of 6PPDQ from 6PPD
Major transformation products from 6PPD
Non-exhaust emissions of PM2.5 and PM10 for EU28 countries