Study on Vehicle Speeds at Single-lane Exit Ramp Terminals on Freeways

Author's Name: Junping Xie, Yongfeng Ma, Li Yuan & Yan Liu
Subject Area: Science and Engineering
Subject Other
Section Research Paper


speed; single-lane exit ramp terminal; freeway; safety


The single-lane exit ramp is the most common style of freeway exit ramp in China, of which the terminal can be divided into two types: taper-type and parallel-type. The main objective of the paper is to elaborate recommendations about the best single-lane exit ramp terminal according to safety. 4 taper-type and 4 parallel-type terminals were selected in Jiangsu Province and the space mean speeds (SMS) of the 200 vehicles on the deceleration lane of each sample were observed. The average SMS standard deviation of taper-type is 7.9 kmph comparing with 4.6 kmph of parallel-type, which indirectly indicates that parallel-type is safer than the other one according to the distinct relationship between crash rate and speed dispersion.

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