Practical Geometric Design of Roadways

This online engineering PDH course provides a detailed description on the geometric design of horizontal alignments, vertical alignments, and cross-sections for modern roadways.

In today's environment, roadway engineers must do more than applying design standards and criteria to "solve" a problem; they must understand how to foster broader community goals, including providing access to employment, schools, businesses and residences, accommodate a range of travel modes such as walking, bicycling, transit, and automobiles, and minimizing fuel use, emissions and environmental damage.

The geometric design of roads is the branch of roadway engineering concerned with the positioning of the physical elements of the roadway according to specific standards and constraints. The basic objectives in geometric design are to optimize the efficiency and safety of the roadway, while minimizing the costs and damages.

The roadway horizontal alignment consists of a series of horizontal tangents, circular curves (simple, compound, and reverse), and spiral transitions. The roadway vertical alignment is a combination of a series of connecting tangent grades and vertical parabolic curves (crest and sag). The roadway cross-section consists of lanes and shoulders, clear zones, curbs, medians, roadside slopes, ditches, and sidewalks. Together, the horizontal alignment, the vertical alignment, and the cross-sections help to provide a three-dimensional roadway layout.

This 8 PDH online course is applicable to traffic or transportation engineers interested in learning about the principles considered when selecting and designing roadway horizontal alignments, vertical alignments, and cross-sections. The contents of this document are intended to serve as guidance and not as an absolute standard or rule.