Monroe's roundabout way of easing traffic congestion

When officials in Monroe realized that they had to do something to relieve congestion at a key intersection, they decided not to resort to old solutions: more lanes, more traffic lights.

Instead, they opted for a project that should keep cars rolling and reduce accidents.

For the past two weeks, a roundabout, or traffic circle, has kept cars flowing through the intersection where the eastbound ramps off Highway 522 meet Tester Road and 164th Street Southeast.

Roundabout grand opening Monroe will hold a ribbon-cutting ceremony at the new roundabout at 10 a.m. today at 164th Street Southeast/Tester Road and Highway 522. There will be refreshments.

Where motorists might get stuck behind traffic lights at an ordinary intersection, here they simply slow as they merge with other cars and circle before exiting onto the street they want.

Roundabouts, long popular in Europe and the eastern United States, are becoming more common in Washington state, especially in fast-growing cities.

The Monroe roundabout, the first in Snohomish County, is different from most in the state in that it has two lanes.

Motorists enter using the outer lane, while the inner lane serves faster and passing vehicles.

There are only two other functioning multilane roundabouts in Washington, says state Department of Transportation engineer Brian Walsh.

Monroe traffic officials began thinking about roundabouts in 1998 after several construction projects, including the new Monroe High School, put a strain on the nearby Highway 522/164th Street Southeast intersection.

Studies indicated a traffic circle, which cost $1.5 million to put in, would cost city and state about $9 million less than building more lanes and installing traffic signals, said Bill Goodwin of Reid Middleton, the Everett-based engineering firm that designed the roundabout.

City officials hope it will save lives as well as money. A study by the Insurance Institute for Highway Safety found that roundabouts have in some cases reduced accidents by 39 percent and injuries by as much as 76 percent.

Two other roundabouts are planned for Monroe, one at Fryelands Boulevard and 164th Southeast, the other where the westbound ramps from Highway 522 enter 164th.

Walsh said there are 21 roundabouts in the state — 18 more than there were three years ago.

In the Puget Sound region, roundabouts already exist in Sammamish and Federal Way and in the Pierce County cities of Gig Harbor and University Place.

Catherine Tarpley can be reached at 206-464-8255 or ctarpley@seattletimes.com.