ITE Journal - March 2021 - 38

A

nnually, nearly 9 percent of all roadway deaths in the United States occur at
rural intersections.1 Modern roundabouts are a Federal Highway Administration

(FHWA) Proven Safety Countermeasure-one good reason why is that rural
intersections converted from stop-controlled intersections to modern roundabouts

have resulted in an 87-percent reduction in fatal and serious injury crashes.2, 3 The roundabouts'
slower speeds, reduced conflict points, and attention to driver expectancy principles create a safe
intersection. These safety results have been consistent throughout the last three decades in the
United States and are in line with the historical experience on international roadways.

Myths of Rural Roundabouts
Despite the documented safety performance of roundabouts at
rural intersections, the public, practitioners, and decision makers
may still have reservations about implementing roundabouts on
high-speed roadways. Contrary to their concerns about the safety of
roundabouts-including the ability of drivers to recognize the intersection and slow down-roundabouts save lives. Other myths include
that roundabouts take up too much right of way and are expensive.
A " right-sized " roundabout accounts for design vehicles and other
common vehicles, and is not overdesigned with unnecessary re-alignments and extensive features that do not add safety or operational
value. Simply put, a rural roundabout can be context-appropriate
and consistent with the intersection environment. The evaluation
of project costs needs to address numerous performance measures,
including safety, operations, maintenance, and environmental
impacts for all users for the life of a project. Often times, preventing
just one severe crash at a rural intersection with numerous safety
risks pays dividends towards a benefit-cost analysis.

of vision is, so on high-speed roadways, it is critical that drivers
" see " the roundabout design features and do not inadvertently
" look past " the roundabout. Addressing driver expectancy is aimed
at ensuring drivers will not fail to notice that there is a changed
condition ahead. This is accomplished in a number of ways,
including geometric approach alignment that allows approaching
drivers to see the central island and promotes visual conspicuity.
Longer splitter islands (than in lower speed environments) can
provide early indication of changing conditions ahead via channelization principles on higher speed roadways.
Safety. Numerous roundabout safety research reports published
over the last 20 years cite the persistent reduction in fatal and injury
crashes at rural intersections with the installation of a roundabout.4,
5, 6, 7
There are several U.S. states that lead the way with implementation of rural roundabouts at some of their highest crash locations
on high-speed rural roadways. Kansas, Maryland, Minnesota,
Washington, and Wisconsin were all leaders in the deployment of
rural roundabouts in the late 1990s and early 2000s. For example,
rural roundabout projects in Duvall, Spokane, and Whatcom County,
WA, USA-as well as dozen more that came afterward-have
maintained significant reductions in fatal and severe crashes. Of
those original seven rural roundabouts in Washington State, a simple
Courtesy Hillary Isebrands.

Rural roadway environments typically include higher speeds (45
miles per hour [72.4 kilometers per hour]+), large trucks, and
infrequent intersections and stops. Roundabout designs in rural
context applications that promote conspicuity allow drivers to
recognize the intersection ahead and react to changing conditions-
including the readiness to slow down and awareness of turning
vehicles-and have impressive safety records when applied to intersections with safety issues or risks associated with severe crashes.

Truths about Rural Roundabouts
Knowing the facts about how rural roundabouts perform is
important when helping an agency decide about safe and efficient
intersection alternatives. The faster we drive, the narrower our cone
38

Ma rch 2021

ite j o u rn al

SR 206/Bruce Rd Intersection, 2005 Roundabout Construction,
Washington State.



ITE Journal - March 2021

Table of Contents for the Digital Edition of ITE Journal - March 2021

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