Impact of Vehicle Type, Tyre Feature and Driving Behaviour on Tyre Wear Emissions Under Real-World Driving Conditions

Abstract

Non-exhaust emissions have become vital contributors to urban air pollutants. Tyre wear emissions, as a major source for non-exhaust emissions, has attracted considerable attention due to adverse impacts on the environment and human health. However, the understanding of emission features from tyre wear is unclear in real-world driving conditions. In this study, the effect of vehicle type and tyre feature on tyre wear emissions was explored by periodically monitoring the tyre wear of a fleet of taxi cars. In addition, a machine learning method (i.e. Extreme gradient boosting (XGBoost)) was used to probe the effect of driving behaviour on tyre wear emissions by monitoring real-time driving behaviour. The current statistical results show that, on average, the emission factors of tyre wear are 57 mg veh-1 km-1 for a hybrid car and 43 mg veh-1 km-1 for a conventional internal combustion engine car. The average emission factor measured for a taxi vehicle configuration featuring winter tyres is 128 mg veh-1 km-1 , which is 1.42 and 3.02 times as much as those with the all-season tyres and summer tyres, respectively. Compared with left-rear tyres, the average emission factor of left-front tyres is 1.75 times. The XGBoost results indicate that compared to driving behaviour, tyre type and tyre position have more important effects on tyre wear emissions. Among driving behaviour, braking and accelerating events have the most considerable impact on tyre wear emissions, followed by cornering manoeuvre and driving speed. Thus, it seems that limiting harsh braking and accelerating has the potential to significantly reduce tyre wear emissions.

Keywords: Non-exhaust emission, Tyre wear emissions, Vehicle type, Tyre feature, Driving behaviour