Brake Dynamometer Evaluation of the Detroit Traffic Road Test

Road testing of friction materials is a complex, time consuming and expensive activity. This paper describes the collection of braking data from a test vehicle having four wheel disc brakes and development of a brake dynamometer simulation test for the Detroit Traffic Road Test. Several dual-ended brake dynamometer simulation tests were conducted in a programmed, unattended mode over weekends where about 1600 road test miles were accumulated each weekend. Feasibility of using dynamometer simulation for road tests was shown by obtaining a correlation in the disc pad wear in both vehicle and dynamometer tests. Temperature effects on wear were seen in both the vehicle and dynamometer tests. Therefore, disc pad temperatures must be closely monitored or controlled during the Detroit Traffic Road Test or its simulation and the effects of temperature must be included in determining disc pad life or to obtain a meaningful comparison between two friction materials.