Research on the quantitative technical index of combining horizontal and vertical curves of expressway

摘要

The factors of combining horizontal and vertical curves are analyzed for guiding road design on expressway in practice and ensuring the safety and comfort of vehicle. The influences on drivers' by all kinds of flat vertical combination characteristics are researched. The necessary conditions meeting the horizontal and vertical combination rationality are proposed through the highway and driver characteristics. The identification sight on convex and concave vertical curve under driving at night and overpass are studied based on driver's sight guidance; the indexes of the vertical curve radius and length that my not meet horizontal including vertical combination are raised. Based on road surface drainage, the indexes that may not meet horizontal including vertical combination is proposed from the aspects of longitudinal slope, cross slope drainage and pavement structure. Comprehensive the design of flat vertical combination put forward the quantitative technical indicators that may not meet horizontal including vertical combination.