Abstract: Highway ridding comfort and road alignment are closely related. A new method that evaluates the comfortableness of highway plane alignment with acceleration and acceleration change is put forward based on the analysis of the vehicle running characteristic under different road alignment. The relatioship among the axial acceleration, lateral acceleration and comfortableness and the evaluation index are expounded. The acceleration changing rate model and acceleration noise model are deduced through the analysis of the influence of change acceleration to ridding comfort. The acceleration noise is used to measure the change size and oscillation frequency of speed, and the discretization model of acceleration noise on the straight, cyclotron and circular curve segment are deduced. A simulation example with different road alignment is given, and the influence of acceleration changing rate to the ridding comfort is analyzed. The changing trend of the acceleration noise is also analyzed on the different plane alignment roads, and the methods of improving the riding comfort are given. Results show that it is a new evaluation method for riding comfort, which provides a reference for the inspection and evaluation of the comfortableness of road geometric alignment.

Key words: road alignment, acceleration change, acceleration noise, changing rate of acceleration, ridding comfort