Research on Model of"Operating Speed and Radius" on Sections of Small Curve Radius for Class II Highway with Two-Lane

The method of survey on the some typical sections of Class Ⅱ Highway with twolane are selected,the data of alignment and speed are collected,the speed data on the radius(R) of 200 m,250 m,300 m,400 m,500 m,600 m,650 m of horizontal curve for passenger cars and medium-sized trucks are analyzed and then the correspond operating speed V85 is gained.After analyzing the operating speed by SPSS software respectively,the operating speed model for passenger cars on Class Ⅱ Highway with two-lane is established.Statistical analysis indicates that the radius R and V85 are related significantly, and the significant probability is 0.The model has high accuracy.At the same time,the moving characteristics of vehicles are analyzed and combined with data which are surveyed on the spot,critical radius of small radius curve for Class Ⅱ Highway,R0 = 610 m,is identified.