An old-fashioned idea is making a come-back on neighborhood streets in Seattle,
Minneapolis, and Madison. These cities are planting small circles in residential street
intersections to slow down traffic.
Traffic circles are 12 to 20 feet in diameter, depending on street width and intersection
radius. Formed by curved curbing, they are usually landscaped with low-growth
vegetation. While all drivers must slow down to negotiate the circle, fire trucks,
emergency vehicles, school buses, garbage and recycling trucks, and snow plows
negotiate them easily.
Seattle, which now has more than 600 circles, has seen lower vehicle speeds and
fewer accidents because of them. Neighborhoods there are competing to have circles
installed, with more than 700 requests coming in each year. The city has developed
selection criteria emphasizing strong community support (60% of all households and
businesses in the area). The request must also satisfy a traffic safety analysis based
on collision, volume, and speed data.
Minneapolis has also adopted the idea, with two traffic circles in place and 32 more
being tested. About 28 will be made permanent this summer. "It improves the esthetic
quality of the street. And drivers see greenery instead of a long strip of asphalt enticing
them to speed," says Mike Monahan, Minneapolis Director of Transportation.
Testing Proves They'll Work
In Minneapolis, each circle gets a two-season experiment (fall-winter or winter-spring)
using portable curb with flower planters inside. This allows residents to try out the
circle in their neighborhood before much money is spent. A formal safety test for
service vehicles involves videotaping each one going through the intersection. Their
cost to install a circle is under $3500 plus $1500 for the test.
Snow plow drivers have to learn how to clear the roadway around the circles on their
routes, which takes a while. With this year's [1996-97] heavy snows, Minneapolis is
plowing more intensively around traffic circles to ensure that fire trucks can pass easily.
"This is the third winter and plow drivers are finally speaking to me again," says
Monahan. "They admit that the circles are not so bad after all." Speeds on
neighborhood streets are definitely lower, but traffic volumes are down only two to five
percent. Monahan attributes the reduction to through traffic leaving residential streets
and returning to arterials.
Residents Must Want Them
Neighborhood support is critical. "People either like them or they absolutely hate
them," says Monahan. Even though traffic turning left may either turn in front of the
circle or go around it, the disruption can produce negative reactions from neighbors, he
In Madison, the circles are a focal point for a new, neighborhood traffic planning
initiative, says City Traffic Engineer David Dryer. "We have a neighborhood with
documented traffic problems and they are willing to work with us as an organization."
He hopes to install the first test circle in late summer.
Dryer had experience with traffic circles in Mobile, Alabama, where he worked until last
year. "We had 20 there, and quite a bit of controversy," he says. "Drivers think you're
nuts but residents like them."
Madison plans to use a mountable 30-inch curb for its permanent traffic circles to allow
a moving van to easily negotiate the intersection, even if it can't quite make the circle.
Neighborhoods will be responsible for maintaining low shrubs and flowers inside the
Speeding is a problem on every street, and we're really hand-tied as to what works to
get motorists to travel at lower speeds," Dryer says. Traffic circles and other traffic
calming devices are widely used in Germany and the Netherlands where they seem to
be effective and well-liked.
(Reprinted with permission from the Spring 1997 "Crossroads," newsletter of the
Transportation Information Center at the University of Wisconsin--Madison)