Construction projects set to begin on 172nd Street

Two construction projects are scheduled to begin this spring on Arlington’s 172nd Street to improve traffic flow and safety.

At 40th Avenue a signal will be put in to improve safety while a roundabout is being constructed at 43rd Avenue, primarily to increase the number of cars that can move through the busy corridor.

In lieu of the usual traffic impact fees, Amazon will be constructing the roundabout at 43rd Avenue and funding the project themselves.

“They will still be keeping the flow of traffic open during construction,” said Jim Kelly, public works director with Arlington.

Cars will still have to slow down a little as they move through the construction zone, he said.

“Traffic will go through the center of where the roundabout will be as the outside is constructed and then go through the outside lanes while the center is constructed,” said Kelly.

Reader boards are planned to alert drivers of the upcoming construction and alternate routes if they need to get onto 43rd Avenue.

“We will have signs for the alternate routes to get onto 43rd Avenue because the cars will not be able to turn onto that road from 172nd Street while the construction is taking place,” said Kelly.

The roundabout is being put in mainly to improve the traffic flow on the street, which is expecting to handle more and more vehicles as development such as Amazon comes into the area.

“This is primarily a mobility improvement,” said Kelly. “Roundabouts are always a much faster way to move cars than signal intersections."

The project is waiting on final permit approval from the Washington State Department of Transportation but could begin as soon as March.

The second project, scheduled to begin in April, is a signal intersection being put in at 40th Avenue and 172nd Street.

“Those improvements will be taking place at nighttime,” said Kelly, so it shouldn’t have much impact on peak traffic times.

“We’re eliminating all of the center turn pockets,” in the area of the project, said Kelly.

That means cars will not be able to make a left turn except at the intersection.

“That is the primary cause of vehicle accidents there,” said Kelly. “The corridor is getting much more development,” he added, which is causing increasing traffic and therefore collisions.

The intersection will allow U-turns as well.

The changes are meant to improve car and pedestrian safety as a large amount of senior housing recently finished next to the intersection.

“We have to provide a safe corridor for the pedestrians,” said Kelly. “We’re also be putting in bus pockets for future bus transit lines in the area."