Roadway Cross-Sections

In Roadway Cross-Sections, you'll learn ...

• General design concepts for roadway cross-sections
• The fundamental design considerations for roadsides: clear zones and lateral offsets
• Drainage design considerations
• Design considerations for curbs and medians
• Noise control design procedures

Overview

Credit: 4 PDH

Length: 51 pages

This course focuses on the geometric design of cross-sections for modern roads and highways and is intended to serve as guidance and not as an absolute standard or rule.

The course objective is to give engineers and designers an in-depth look at the principles to be considered when selecting and designing roadway cross-sections. Upon course completion, you should be familiar with the general guidelines for roadway cross-section geometric design.

A Policy on Geometric Design of Highways and Streets (also known as the “Green Book”) published by the American Association of State Highway and Transportation Officials (AASHTO) is considered to be the primary guidance for U.S. roadway design. For this course, Chapter 4 - Cross-Section Elements will be used exclusively for fundamental roadway geometric design principles.

The AASHTO “Green Book” defines a roadway cross-section as “a vertical section of the ground and roadway at right angles to the centerline of the roadway, including all elements of a highway or street from right-of-way line”. Along with the vertical alignment (grades and vertical curves) and horizontal alignment (tangents and curves), the roadway cross-section (lanes and shoulders, curbs, medians, roadside slopes and ditches, sidewalks) helps provide a three-dimensional roadway model. Its ultimate goal is to provide a safe, smooth-flowing facility that is crash-free.