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Roundabout Geometric Design

COURSE NO: C04-004
COURSE PROVIDER: Gilbert Gedeon, P.E.
Roundabout Geometric Design
Course Highlights

This online engineering PDH course presents the fundamental design principles common among all roundabout types. This course also presents detailed design considerations specific to multilane roundabouts, rural roundabouts, and mini-roundabouts.


Designing the geometry of a roundabout involves choosing between trade-offs of safety and capacity. Roundabouts operate most safely when their geometry forces traffic to enter and circulate at slow speeds. Horizontal curvature and narrow pavement widths are used to produce this reduced-speed environment. Conversely, the capacity of roundabouts is negatively affected by these low-speed design elements. As the widths and radii of entry and circulatory roadways are reduced, the capacity of the roundabout is also reduced.


Furthermore, many of the geometric parameters are governed by the maneuvering requirements of the largest vehicles expected to travel through the intersection. Thus, designing a roundabout is a process of determining the optimal balance between safety provisions, operational performance, and large vehicle accommodation.


This 4 PDH online course is applicable to traffic engineers, transportation planners, managers, and other technical professionals who are involved in the geometric design of roundabouts.

Learning Objectives

This PE continuing education course is intended to provide you with the following specific knowledge and skills:

  • Familiarizing with the different types of roundabouts
  • Understanding the geometric elements
  • Learning the general design principles
  • Selecting the appropriate inscribed circle diameter
  • Designing the alignment of approaches
  • Designing entry and exit curves
  • Designing the central and splitter islands
  • Determining the stopping and intersection sight distances
  • Designing methods to avoid vehicle path overlap
Course Document

In this professional engineering CEU course, you need to review Chapter 6, "Geometric Design", of the Federal Highway Administration Publication FHWA-RD-00-067, "Understanding Roundabouts".

To view, print and study the course document, please click on the following link(s):
Roundabout Geometric Design (2.2 MB)
Course Quiz
Once you complete your course review, you need to take a multiple-choice quiz consisting of twenty (20) questions to earn 4 PDH credits. The quiz will be based on the Chapter 6 of this FHWA publication.
The minimum passing score is 70%. There is no time limit on the quiz, and you can take it multiple times until you pass at no additional cost.
Certificate of Completion

Upon successful completion of the quiz, print your Certificate of Completion instantly. (Note: if you are paying by check or money order, you will be able to print it after we receive your payment.) For your convenience, we will also email it to you. Please note that you can log in to your account at any time to access and print your Certificate of Completion.

To buy the course and take the quiz, please click on: