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Efforts to develope a harmonized brake standard have led to the developement and evaluation of procedures for measuring the brake balance and braking efficiency of passenger cars. The European braking regulations include a procedure for direct measurment of the braking efficiency of a vehicle equiped with an antilock system (ECE Regulation No. 13. Annex 13/EEC Directive 71/320 Annex X). The procedure is a two step process including the measurement of the peak coefficient of friction (mu) for the vehicle tire on the test surface, and then finding the maximum deceleration of the vehicle on the test surface for calculation of the braking efficiency. Tests were conducted to evaluate the feasibility of using this procedure for vehicles not equiped with ABS. Comparisons were made between the peak coefficient of friction as measured by the Annex 13 procedure and as measured by a traction trailer with the vehicle tires installed.

Currently there are no adequate standards or regulations that address the performance of aftermarket replacement brake linings to insure that the use of these materials does not degrade vehicle braking performance from the original equipment (OE) design intent level. This paper discusses the results of an evaluation of a large sampling of aftermarket linings available for the rear brake of a specific model passenger car and shows that many of these linings have significantly different performance than the OE material. The paper also shows how this deviation can adversely affect vehicle braking efficiency or the ability of the brake system to utilize available tire/roadway friction without locking wheels and losing control.