Abstract: Theoretical analysis and actual test are conducted with new and old tires，and the curves of initial speed-braking distance and initial speed-mean braking deceleration are established respectively，with the polynomial fitting of test data.From the comparison between two kinds of tires’test data，the conclusion is drawn that the new tire’s braking efficiency is better than the old one obviously，and the degree of wear has a great influence on braking efficiency，which would affect the driving safety of vehicle furthermore.

Key words: braking efficiency, retarded velocity, braking distance, polynomial fitting

摘要： 以全新轮胎与旧轮胎为例进行理论分析和装车试验，对试验数据进行多项式拟合，分别建立制动初速度-制动距离和制动初速度-平均减速度关系曲线。研究表明: 新胎车辆的制动效能明显优于旧胎车辆的制动效能，说明轮胎的磨损程度对车辆的制动效能有很大的影响，并进一步影响到车辆的行驶安全性。

关键词: 制动效能, 减速度, 制动距离, 多项式拟合