Real-World Emission Dynamics of Tire and Road Wear Particles: Impacts of Micro-Driving Behaviors and Roadway Characteristics

Abstract

With the decline of exhaust emissions, non-exhaust sources─particularly tire and road wear particles (TRWP)─have emerged as a dominant contributor to vehicular pollution. This concern is amplified by projections indicating substantial increases in TRWP emissions due to the growing electric vehicle fleet. However, a comprehensive understanding of TRWP generation under real-world micro-driving conditions remains limited. In this study, we investigated near-wheel TRWP-related PM concentrations using an instrumented vehicle operated on an access-controlled road network comprising highways, suburban streets, and rural roads. A wide range of micro-driving behaviors─including steady-speed travel, acceleration, deceleration, lane changes, cornering, merging, stop-and-go driving, and U-turns─were evaluated in conjunction with roadway design features such as pavement type, roadway grade, and horizontal curvature. Real-time measurements revealed that each micro-driving maneuver exerts a distinct influence on TRWP-related PM concentrations and differentially contributes to fine or coarse particle generation, with the PM2.5 fraction of PM10 ranging from 0.49 to 0.82 across driving conditions. Additionally, roadway characteristics such as curve radius, pavement type, and roadway grade substantially affect measured particle concentrations. These findings provide a comprehensive quantification of how driving behaviors and roadway characteristics influence near-wheel TRWP-related PM concentrations, offering actionable insights for road design optimization and supporting the development of future non-exhaust emission regulations.