Roundabout Geometric Design

Gilbert Gedeon, P.E.

About Gilbert Gedeon, P.E.

Mr. Gilbert Gedeon is an online PDH course provider of continuing education courses for professional engineers.


Mr. Gedeon is a Registered Professional Engineer in the States of New York and New Jersey. He holds a Bachelor of Science in Civil Engineering and Master of Science in Environmental Engineering from New Jersey Institute of Technology. Mr. Gedeon is a member of the American Society of Civil Engineers. He is also a member of the National Society of Professional Engineers. He also serves on the board of New York State Society of Professional Engineers, Rockland County Chapter. Mr. Gedeon has developed numerous continuing education courses for professional engineers pursuing PDH credit for their license renewal.


Mr. Gedeon has over 23 years of diversified project engineering and management experience within the civil and environmental industry. He has provided a wide range of civil and environmental engineering services in support of capital improvement projects ranging from $100 thousand to $30 million. His professional practice involved remedial inspection and design of building toxics/hazardous material, design and supervision of subsurface investigations, monitoring well design and installation, groundwater plume delineation and analysis, upgrade/closure of underground storage tank systems, supervision of waste water treatment plant operation, development and review of spill prevention control and counter-measure (SPCC) plans, compliance audit management, supervision of excavations, shoring system installations, and geotechnical borings.


Mr. Gedeon has special expertise in the development of project specifications, design drawings, technical reports and cost estimates. He has managed contract documents from production to execution including proposals, bid evaluations, contract negotiations and award, review and approval of contractor submittals. Mr. Gedeon has extensive experience in operations management, account and project administration, client development and regulatory relations, corporate policy implementation, profit/loss analysis, personnel hiring and development, resource allocation and quality assurance.


COURSE NO: C04-004
PRICE: $96


Course Highlights

This continuing education online PDH course is NY approved. This course is also accepted in the States of AK, AL, AR, DE, FL, GA, IA, ID, IL, IN, KS, KY, LA, MD, ME, MI, MN, MO, MS, MT, NC, ND, NE, NH, NJ, NM, NV, OH, OK, OR, PA, SC, SD, TN, TX, UT, VA, WI, WV and WY.

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 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.


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


In this course, you need to review Chapter 6, “Geometric Design”, of the Federal Highway Administration Publication FHWA-RD-00-067, "Understanding Roundabouts" provided below. 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. 


Learning Objectives

This 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

To view, print and study the course document, please click on the following attachment(s):

Roundabout Geometric Design (1.87 MB)

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Course Quiz

To earn your PDH credits, you will need to buy the course and take the quiz by clicking on the following link:

Buy the Course and Take the Quiz

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