The Design and Phasing of Horizontal and Vertical Alignments: Program JANUS,

摘要

The report outlines some of the factors which influence the geometric design of rural roads,with emphasis on the vertical alignment,and describes the geometric design standards currently recommended for motorways in the United Kingdom. It discusses the phasing of the vertical alignment with the horizontal alignment required to present a visually pleasing design and to avoid the creation of hazards. The concept of phasing is extended to include the total separation of the vertical and horizontal curves,the phasing of one end only,or the phasing of both ends of the curves,depending on the type of mis-phasing and the radii of the curves. Critical values of radius at which phasing is required are determined by the engineer. (Author)