Safety Prediction System For Section Of Downgrade-followed Curve Of Freeway

In this paper, I review the research status quo of road safety design firstly and analyze its insufficiency and blank sites, thus establish my object of research - the influence that the combined alignment of downgrade-followed curve brings on road safety. Accordance to the research object and content, research method is set down, taking the speed as intermedium, via the relation that alignment influences speed and speed results in traffic accidents, to analyze the law of alignment and road safety. The technology route adopted is trial route based data from factual survey. In the paper, examination method and process is described in detail. Based on the GPS data, I analyzed the velocity track of swatch roads and concluded velocity characteristic curve of alignment of downgrade-followed curve, in addition put forward alignment range and conditions responding to velocity characteristic curve. Based on geometry alignment data and speed difference, by stat. Formula are established about the relation between downgrade, curve radius and deflection and speed change. Then method to establish speed characteristic curve is present. And then acceleration characteristic curve is concluded based acceleration track and point out its wave segment. Combined with traffic accidents, the correlativity between accident and acceleration change is setup.