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Aroused
about Roundabouts
In
many locations, roundabouts can handle more
traffic than signal lights. They're safer and
cheaper to maintain. Why, some experts wonder, isn't Virginia building more of them?
By
Bob Burke
Traffic
lights still rule the roads, but in a roundabout
way, transportation planners in Virginia are
learning a new way to design intersections.
Widely
used in Australia and many European countries,
roundabouts are gaining in popularity in Virginia
and across the U.S. Today there are only about a
half-dozen roundabouts in the state, but in the
past three years transportation planners have
approved 21 more. Another 19 are under review, and
more are entering the pipeline.
Roundabouts
aren’t the whole solution for easing
transportation congestion, but they can sometimes
work better than traffic signals. “Whenever you
look at [using] a traffic signal you should look
at the roundabouts as a viable alternative,”
says Walter Pribble, a senior transportation
planner with the Virginia Department of
Transportation and a member of panel that reviews
roundabout proposals. “It’s one tool in the
toolbox.”
The
popularity of roundabouts is scattered around the
state. There’s one in Albemarle County near the
entrance to the Charlottesville Albemarle Regional
Airport. Virginia Tech and Christopher Newport
University each have one, as does Gloucester
County, which uses a roundabout to feed traffic
into a retail project anchored by Wal-Mart and
Home Depot.
Also
among the proposed roundabouts are five at the
Farms of New Kent, an upscale 2,300-unit project
planned in New Kent County. If approved, two of
the roundabouts would be at the intersection of
Interstate 64 and Route 106, eliminating the need
for a full cloverleaf intersection.
Roundabout
in Columbia, Missouri
Supporters
of roundabouts cite their advantages in safety,
cost and capacity. Roundabouts have been shown to
reduce fatal and injury accidents by up to 75
percent, because drivers travel slower and have
less crossing traffic to keep track of, according
to VDOT. An intersection of two two-lane roads,
for example, has 32 vehicle-to-vehicle conflict
points, compared to eight for a roundabout.
While
Roundabouts cost roughly the same amount to
construct as a traditional criss-cross
intersection, they’re cheaper to maintain. Plus,
they can handle more traffic than a traditional
signaled intersection or four-way stop, where
motorists must pull to a dead stop and wait. A
double-lane roundabout, for example, can handle up
to 50,000 vehicles a day. With the Commonwealth
hard pressed to keep up with the growth in
traffic, roundabouts would appear to be a
cost-effective alternative to conventional
intersection design.
Roundabouts
work by giving drivers a simple and safer chance
to decide when it’s safe to proceed. Traffic
entering a roundabout has to yield to circulating
traffic, and moves at a slower speed. And since
everyone’s traveling in a counterclockwise
direction, drivers only have to look left to
decide when to proceed.
If
roundabouts are so effective, however, why did
traffic planners ever stop using them? Proponents
say part of the reason is the bad experience that
many in the U.S. had in the early 20th century
with traffic circles -- examples familiar to
Virginians are the circles around the Lee and
Stuart monuments in Richmond and DuPont Circle in
Washington, D.C. -- which differ from
roundabouts in key ways. For one, circles
sometimes require traffic in the circle to yield
to vehicles entering it, which can bring traffic
flow to a halt. Circles are also larger, and
encourage higher-speed merges and weaving
traffic.
By the 1950s, many traffic circles were so
unworkable that engineers began adding traffic
signals to control the flow of vehicles, or
replaced them entirely. That helped create an
institutional resistance to roundabouts that still
exists today. “Even in VDOT, when you hear the
word roundabouts, they confuse it with the old
circles and the rotaries they have up in New
England,” Pribble says. Persuading some traffic
engineers to use roundabouts means “you have to
overcome the misconceptions.”
Another hurdle is drivers, who are inexperienced
with using roundabouts, says Harrison Rue,
executive director of the Thomas Jefferson
Planning District Commission and a strong advocate
of roundabouts. Much of that stems from being
unfamiliar with how roundabouts work, he says.
The
new roundabout opened in Albemarle last fall
worked well because it was clearly marked with
signs explaining the flow of traffic to
approaching vehicles, he says. “If property is
signed from the beginning there really doesn’t
seem to be a learning curve.”
A key reason VDOT now supports the concept,
Pribble says, is a 2003 General Assembly
resolution sponsored by Del. Mitch Van Yahres,
D-Charlottesville, that urged VDOT to back their
use. Also, private-sector developers are
increasingly interested in choosing a roundabout
instead of an intersection, he says, because
“you can do away with stop signs and signals and
have a down home feeling.” Roundabouts can be
landscaped to look more appealing than an
intersection, he says.
Nationwide, the number of roundabouts runs to more
than 600 by some estimates. Other states – such
as Florida, Colorado, Maryland and New York - are
ahead of Virginia in adopting the practice,
Pribble says. A leader is New York, where the
first modern roundabout was built in 1904. The
state is
pushing roundabouts as the default option for
intersections, and only choosing traffic signals
if a roundabout won’t work. “In Virginia
we’re not there yet,” he says. “We’re
looking at both options and judging which one will
be better.”
Rue says the new federal transportation bill
passed last year could help boost the use of
roundabouts. It adds roundabouts to the list of
projects eligible for 100 percent federal funding.
Pribble says Virginia isn’t committing any
additional funds to increase the use of
roundabouts but will keep pushing them as a
potential alternative. “We are going to do our
best to educate and promote roundabouts because
they’re a viable option and a safe option.”
Bacon's
Rebellion News Service
February
10, 2006
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