Safety Evaluation Model Based on Alignment Synthetical Index of Expressway

Abstract:

In order to investigate comprehensively the relationship between alignment index and road safety,the research puts forward the concept of road alignment synthetical index based on design indices such as curvature and its changing rate,curve angle,lognitudinal gradient,lanewidth,lane number,and shoulder widths.Road alignment synthetical index evaluation model is also established which provides theory evaluation method for the quantitative analysis of highway alignment.The relationship is obtained between accident rate and alignment synthetical index accumulative total value through the regression analysis.The regressive results certify that the road alignment synthetical index can be chosen to evaluate the road alignment quality and road safety and better correlation exists between accumulative total value and accident rate while the correlative model between accident rate and synthetical index accumulative total value is established.Based on case studies,a safety evaluation standard is proposed.

Key words:highway alignment; alignment synthetical index; evaluation model; safety evaluation; accident rate