Print this page Modern Roundabout Design
Gregory J. Taylor, P.E.
Course Outline
The modern roundabout is a common intersection application which is becoming increasingly popular in the U.S. As with any intersection, its selection and design requires balancing competing objectives (economics, safety, environmental concerns, operation, accessibility, land usage, aesthetics, etc.).
This six-hour course is a summary of the geometric design process for modern roundabouts. The main objective is to give engineers and designers an in-depth look at the principles to be considered when selecting and designing roundabouts. It is important to understand these design principles as well as the potential trade-offs that may be encountered. By combining this course material with work experience and engineering judgment, the designer may produce plans that greatly benefit the traveling community.
Upon course completion, the participant should be familiar with the general design guidelines for modern roundabouts.This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of the course materials.
Learning Objective
At the conclusion of this course, the participant will:
- Understand the history of early traffic circles and rotary intersections;
- Be familiar with general design process for modern roundabouts;
- Recognize the advantages and disadvantages of roundabouts;
- Be familiar with basic geometric elements;
- Know the various principles and objectives for roundabout design;
- Be familiar with the design of different types of roundabouts;
- Recognize the various types of roundabout performance checks;
- Understand the design and placement of traffic control devices; and
- Be familiar with signage and pavement marking options.
Intended Audience
This course is intended for landscape architects, engineers and contractors.
Benefit for Attendee
Attendees of this course will be given an in-depth look at geometric design principles to be considered for modern roundabouts.
Course Introduction
Roundabout geometric design is a combination of balancing operational and capacity performances with the safety enhancements. Roundabouts operate best when approaching vehicles enter and circulate at slow speeds. By using low-speed design elements (horizontal curvature and narrow pavement widths for slower speeds) the capacity of the roundabout may be negatively affected. Many of the geometric criteria used in design of roundabouts are also governed by the accommodation of over-sized vehicles expected to travel through the intersection.
Course Content
The course content is contained in the following PDF file:
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Course Summary
The modern roundabout is a common intersection application which is becoming increasingly popular in the U.S. As with any intersection, its selection and design requires balancing competing objectives (economics, safety, environmental concerns, operation, accessibility, land usage, aesthetics, etc.). Therefore, it is crucial to provide sufficient flexibility for tailoring the roundabout’s design to its particular situation.
The intention of this course was to explain some principles of good roundabout design and show potential trade-offs that may be encountered. By combining these principles with work experience and engineering judgment, the designer may produce plans that greatly benefit the traveling community.
Related Links and References
The following reference books were used by the author in the preparation of this course:
Transportation Research Board www.trb.com
FHWA Safety Program safety.fhwa.dot.gov/intersection
Quiz
Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.
DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.
