Geometric design for transportation facilities includes the design of geometric cross
sections, horizontal alignment, vertical alignment, intersections, and various design
details. These basic elements are common to all linear facilities, such as roadways,
railways, and airport runways and taxiways. Although the details of design standards
vary with the mode and the class of facility, most of the issues involved in geometric
design are similar for all modes. In all cases, the goals of geometric design are to maximize
the comfort, safety, and economy of facilities, while minimizing their environmental
impacts. This chapter focuses on the fundamentals of geometric design, and
presents standards and examples from different modes