| Welcome
to the Modern Roundabouts Web site
This
Web site serves as one of the definitive sources on Modern Roundabouts
and is a complement to the Federal Highway Administration's research
project aimed at developing a comprehensive guide to roundabouts design.
The results of this project are contained in the book published by
FHWA in August 2000; Roundabouts:
An Informational Guide.
Roundabouts
are a common form of intersection control used throughout the world.
However, many state and local agencies throughout the United States
have been hesitant to install roundabouts due to a lack of objective
nationwide guidelines on planning, performance, and design.
Prior to the development of Roundabouts: An Informational Guide,
the few state and local agencies interested in roundabouts had to rely
on foreign roundabout design guides, roundabout proponents, or in some
states, statewide roundabout design guides. Roundabouts require strict
conformance to standard practice to ensure safe, optimal operation,
and this scattered approach to design can lead to inconsistencies at
a national level which are consequential in terms of driver expectation
and safety. To address this national need, the Federal Highway Administration
selected a worldwide team of experts to develop Roundabouts: An
Informational Guide.
Roundabouts: An Informational Guide addresses the following
topics:
- Definition
of a roundabout and what distinguishes roundabouts from traffic circles;
- Methodology
for identifying appropriate sites for roundabouts and the range of
conditions for which roundabouts offer optimal performance;
- Methodology
for estimating roundabout capacity and delay;
- Design
principles and standards to which roundabouts should conform, including
applicable national standards such as the AASHTO Policy on Geometric
Design of Highways and Streets and the Manual on Uniform Traffic Control
Devices;
- Consideration
for all modes, including heavy vehicles, buses, fixed route transit,
bicycles, and pedestrians;
- Guidelines
for operational features such as signing, pavement markings, illumination,
and landscaping;
- Public
acceptance and legal issues associated with roundabouts.
The pages
of this Web site collect and make available much of the information
generated from this FHWA project including:
- A database
of currently operating or planned roundabouts. You can search the
current records in the database or add new sites that are not yet
listed.
- An outline of Roundabouts: An Informational
Guide.
- A listing
of other resources on roundabouts, including articles,
papers, books, design guides, and videotapes.
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