公路三维动态视距计算方法及评价技术

提出了利用三维动态视距表征公路有效视距的思路和方法。该方法以平纵线形数据为数据源,利用三次B样条曲线拟合公路线形。综合考虑平纵线形组合、驾驶员动态视野和车前灯照射范围等因素,以驾驶员视点和视距验算点的连线与视线中心线间的夹角与驾驶员在该方向上最大动态视角的关系作为约束条件,采用空间几何向量关系进行计算。同时还提出了三维动态视距评价标准,以辨识视距不良路段,分析视距受限的原因。最后通过一个实际案例对本文方法的计算结果进行了验证,结果表明:该方法易于获取数据源,便于推广使用,为路线安全设计提供了技术支撑。

Calculation and assessment technique of highway 3D dynamic sight distance

A method of using Highway 3D Dynamic Sight Distance(H3DSD) to represent the available sight distance was proposed.The geometric data was used as the main data source for H3DSD calculation.The data was used to fit the highway alignment with cubic B-spline curves.Considering the influencing factors of combination of horizontal and vertical alignment,the driver′s dynamic visual field,and the illumination angle of the vehicle head lamps,the H3DSD of each point along the centerline roadway could be calculated with spatial geometry.The most important constraint during the calculation was the relationship between the computed angle composed by the line from the position of driver′s eyes to the sight distance checking point and the centerline of the driver's visual field,and the driver′s maximum dynamic visual angle.Moreover,the criterion of H3DSD was proposed in order to identify the segments with poor sight distance.Also the main factors restricting sight distance were analyzed.A case study was carried out and the results show that the proposed method has the advantages of easy to get the source data and good prospect of application.It can provide significant technique support to highway safety design.