Design of roadway test system for motor vehicle brake performance and its evaluation methods

Service braking test and evaluation are of importance for vehicle braking performance. The vehicle braking performance roadway test system was firstly designed in the paper, whose main instrument was GPS-based VBOX III. Then the systematic vehicle braking performance tests were conducted on the vehicle proving ground. Based on the real straight-line braking test data, two indexes, braking distance and mean fully developed deceleration (MFDD) according to rules and regulations for braking performance test, were analyzed respectively and comparatively. The results shows that, MFDD index can avoid the effect of driver´s operation or braking system reaction time on braking performance, so this evaluation method is more objective. However, braking distance index reflects the comprehensive effecting of human-vehicle system and obtains the integrated evaluation.