Speed and Design Consistency of Combined Horizontal and Vertical Alignments in Two-Lane Rural Roads
One of the most important equations in highway design is the formula for the minimum radius of horizontal curve which considers the design speed of the highway, the superelevation, and the side friction factor. Traditionally, differences in the highway vertical alignment features, which are prevalent at areas with rolling and mountainous terrains, are not considered in this part of the design process. Past research has indicated that drivers perceive horizontal curves differently when compared with highway sections in which both horizontal and vertical curves overlap.