The Evaluation Of Highway Alignment Design Based On Possible Speed

At present, there is just one qualitative description, without a clear quantitative index in the standard and regulation of our country. So how to evaluate highway alignment design is difficult. And it resulted in the problems of designing quality and traffic safety, which had a crucial effect on the society and economy of China. A scientific and rational evaluation standard is urgent needed. For this reason, research on the evaluation of highway alignment design was carried out in the paper.Firstly, the concept of the possible velocity was introduced in the paper. And its influence factor and computing method were analyzed. In the same time, the predict model of possible velocity was set up. The results indicated the possible velocity was not only influenced by geometric condition of the highway, but also restricted by the axial velocity, transverse velocity and vertical velocity.Secondly, the feasibility of this new method was analyzed.in the paper. The thesis put forward the velocity difference as the evaluating standard in highway alignment design and the difference measurement to establish the evaluating index of different classes of highway. It also set up steps of drawing graphs of possible velocity, judging design quality and safety, and deciding on modifying spots.With the relations between highway alignment, operating speed and transportation safety, the safety evaluating standard based on the possible velocity was set up. The corresponding evaluation index C was provided, which had obvious relevance with traffic accident. The results indicated the greater C value was, the better traffic safety state of the road was.Finally, adopting the possible velocity model and evaluation index and method set up in the paper, this text gave the evaluation conclusion about the project instance, a secondary road of one province had proved that it was helpful to the highway alignment design of our country.