Discussion on Relationship between Expressway Crash and Horizontal Alignment

Constructing function model between crash and road geometric/traffic variables using statistical tool is one of the most(important) method in crash analysis and prediction.More variables included in model may improve goodness-of-fit,but this will make model more complex and make data collection more difficult.Thus,the authors focused on the relationship between horizontal alignment variables and crash in this paper,and typical horizontal alignment variables include circular curve,curve length,spiral curve,(superelevation,)etc.First,the authors made a literature review,introduced relevant research results comprehensively.Second,two(regression) models were developed by using SPSS tool,with crash,geometric and traffic data of GuiHuang and GuiXin expressway in Guizhou province.Additionally,the effect of superelevation on road safety was analyzed based on practical case,with some suggestions and countermeasures on safety improvement of horizontal alignment.