Improved Length Coefficients of Speed-Change Lanes on Highway Gradient

The lengths of speed-change lanes of highway are composite with the lengths of the transition section and the lengths of the acceleration or deceleration lane lengths. The equations of modification coefficients of speed-change lane length on gradients are brought forward according to the operated performance of vehicle. The accelerated and decelerated levels of typical vehicles are studied, furthermore, the relationship between gradient and speed-change lane length is discussed, and modification coefficient of speed-change lane length on gradient is given out. Finally, compared with Design Specification for Highway in China, the values of improved length coefficients of speed-change lane are put forward. The results of analysis could be used as design references for people who designed highway in mountain areas.