Roundabouts
Unsignalised roundabouts provide a safe and efficient form of intersection
control. They have been used extensively in the Australia and Europe, and
are being increasingly popular in the USA (where the term "modern roundabout"
used). This page provides information about modern roundabouts with an
emphasis on capacity and level of service analysis methods.
Roundabout Capacity Methods and Software Used in the USA
Extract from Modern Roundabout Practice in the United States
NCHRP Synthesis 264, Transportation Research Board, 1998
"There are two primary capacity methods and software programs used in the United
States: the Australian method with the SIDRA software and the British method
with either the RODEL or the ARCADY software. ... SIDRA appears to
be the most commonly used in the United States. This is in line with the
fact that two-thirds of the survey respondents mentioned that they followed, or
at least consulted, the Australian guidelines for roundabout design. ... "
Also see:
SIDRA INTERSECTION for Roundabouts
Roundabout Model Comparison Table
Traffic Analysis Software Tools (TRB)
Useful US Website links on Roundabouts
The following are links to roundabout websites in the USA that contain useful
information.
Roundabouts in
Virginia
Oregon DOT Roundabout website
Washington State DOT
Roundabout website
Traveling
Maryland's Roundabouts
Kansas State University Roundabout
website
Multi-Lane Roundabouts
The following is a useful document on the use of multi-lane roundabouts:
RTA NSW Roundabouts Guide
Articles on Roundabouts
Numerous articles are available for download on our website:
Downloads
Articles on Roundabouts
Roundabout Photos
Please download these roundabout photo presentations for your personal use only
(permission required for commercial or
any other use).
Bend & Clearwater Roundabout Photos
Made available 10 Aug 2004
Contact us for PowerPoint version.
Australian Roundabout Photos
Updated 3 Oct 2003
Contact us for PowerPoint version.