Abstract
TRAFFIC NOISE CAN BE A SIGNIFICANT SOURCE OF URBAN POLLUTION AND AS SUCH MUST BE REDUCED. VEHICLE NOISE RESULTS FROM THE COMBINATION OF SEVERAL SOURCES, EACH OF WHICH REQUIRES ATTENTION IN ORDER TO REDUCE OVERALL LEVELS. THIS PAPER DEALS WITH WHAT IS CONSIDERED A MAJOR SOURCE MECHANISM OF TYRE/ROAD NOISE, NAMELY THE DISPLACEMENT AND REPLACEMENT OF AIR TRAPPED BETWEEN THE TYRE AND ROAD. SPECTRAL AND DIRECTIONAL ANALYSES WERE MADE OF THE NOISE GENERATED BY TYRES OPERATING ON A DRUM ROLLER IN AN ANECHOIC CHAMBER. TREAD DEFORMATIONS WERE OBSERVED AND A MATHEMATICAL MODEL DEVELOPED. AN UNDERSTANDING OF THE MECHANISM HAS BEEN ACHIEVED. (A). FOR THE COVERING ABSTRACT OF THE CONFERENCE PROCEEDINGS SEE IRRD ABSTRACT NO. 226354.