In general, the state Department of Transportation prefers to install roundabouts versus other intersection types. (WSDOT)

In general, the state Department of Transportation prefers to install roundabouts versus other intersection types. (WSDOT)

How and why an intersection gets redesigned in Washington

The most common question submitted to Street Smarts: How do I get a roundabout installed?

Emails about intersections Street Smarts readers find treacherous have begun to accumulate in my inbox. Drivers want to know how they can get an intersection redesigned.

Just recently, I heard from Everett Lewis, who wanted the state Department of Transportation to re-evaluate the intersection of Highway 530 and 211th Place SE. He said drivers speed down 530 making it difficult for vehicles trying to turn left from 211th.

Lewis recommended installing a roundabout there, which he said could help reduce accidents and slow speeds as population growth continues to explode in that area.

Will Brandt also proposed a roundabout where Highway 9 and Highway 92 cross in Lake Stevens. And he took issue with where 60th Street NE crossed the highway.

These are just a few of the emails wanting to know how to catch WSDOT’s attention about a particular intersection. Instead of inundating WSDOT with all the requests and waiting for answers, many of which would likely disappoint the traveler, I thought I’d walk through the transportation agency’s procedure for considering whether an intersection needs to be redesigned, known as an Intersection Control Evaluation report.

A variety of things can trigger this five-step analysis, including a request from the public or elected leader. Or a history of safety or operational issues. A new development can also start the process.

“The purpose of completing an Intersection Control Evaluation report is to ensure the change fully addresses the long-term need in a cost-effective manner,” said Joseph Calabro, a spokesperson for WSDOT.

Intersections aren’t required to have a certain volume of cars or crashes to begin the review, he said.

Step 1. After an intersection is selected for the evaluation, data on traffic volumes and how vehicles move through the intersection is collected. The agency looks at all possible alternatives based on the need and site conditions.

A goal for a redesigned intersection is also established at this point.

Step 2. In this phase the feasibility of the designs are evaluated. A sketch of each potential project is done to determine the space required and if any environmental risks exist.

Step 3. WSDOT then uses a computer to model current and future traffic conditions under the alternative designs being considered to evaluate how each would operate.

Crashes and causes over the last five years are also analyzed. Designs are run through a traffic safety computer model that predicts if accidents would be reduced.

A scenario where no changes are made is also studied.

Step 4. The alternatives are measured against each other. This includes comparing cost estimates, savings in travel times and how each meets the goals set out in step 1.

Step 5. A recommendation is selected.

In general, WSDOT’s preference is to install roundabouts when possible, Calabro said.

“Roundabouts are proven to be the safest for motorists and pedestrians,” he said.

The public is also given a chance to comment. In general, when that is done, several designs are put forward.

Funding then probably needs to be secured before anything actually happens.

Got a question? Email me at streetsmarts@heraldnet.com or call 425-374-4165. Please include your name and city of residence.

Talk to us

More in Local News

25 years later, they still hope to find their daughter’s body

For her parents, detectives and prosecutors, it’s less a whodunit than a question: Where’s Tracey Brazzel?

Homeowner allegedly shoots, kills burglar in Everett

The homeowner, in his 70s, reportedly heard noise and confronted a burglar, in his 30s.

Boeing cutting more than 12,000 jobs with layoffs, buyouts

The company said it will lay off 6,770 workers this week, and another 5,520 are taking buyouts.

Everett man identified as victim of deadly gunfire at party

William Thomas Harper III, 28, was shot to death Sunday. His alleged assailant is jailed.

2 more sentenced in killing of Everett homeless man

Three people were involved in a robbery during which Michael Boone was tied to a tree and left to freeze.

Registration open for drive-thru virus testing in Snohomish

Tests will be administered Thursday at the Sno-Isle Libraries branch on Maple Avenue.

Worst jobless rate in the state: Snohomish County at 20.2%

In April, 91,383 were unemployed in the county. The aerospace sector was hit especially hard.

Burglary suspect identified after fatal Everett break-in

A homeowner shot the man Thursday morning. The slain man had served much of his adulthood in prison.

After 3 weeks in hospital, Marysville man dies from gunshot

Joshua M. Klick, 31, was shot during a reported burglary in Arlington, according to police.

Most Read