ABSTRACT
The present work discusses the friction coefficient displayed by bare foot and footwear soles sliding against polypropylene brake pedal pads. The frictional performance is compared to that obtained from the rubber conventional pads. Measurement of friction coefficient is, therefore, of critical importance in assessing the proper friction properties of brake pedal pads and their suitability to be used in application to enhance the safety of the vehicle. The reduction in friction coefficient displayed by bare foot and rubber footwear soles sliding against the tested brake pedal pads in dry, sand contaminated, water and oil lubricated conditions is discussed.
 
It was found that, for bare foot sliding against the tested pedal pads at dry sliding, friction coefficient displayed by PP tested pads was relatively lower than that shown by the conventional and transverse ones. In the presence of sand particles between the foot and the tested pads, friction coefficient increased significantly for PP pads. PP pads displayed the lowest friction coefficient for bare foot sliding against water wetted pads in the longitudinal direction. For oil lubricated pads, values of friction coefficient displayed by PP pads were close to that presented by conventional pads. The experimental findings of rubber footwear slid against the tested pedal pads, rubber shoes displayed relatively lower friction values than bare foot at dry sliding. In the presence of sand particles on the sliding surfaces, friction coefficient significantly increased for PP pads for longitudinal and transverse direction. The worst condition was observed for PP pads when sliding against water wetted foot wear, where drastic decrease in friction coefficient was displayed. At oil contaminated sliding, values of friction coefficient were close to that displayed by bare foot. PP pads displayed relatively higher friction than the conventional pads, while the transverse pads indicated the highest friction values.