Thursday, May 22, 2014

Two intersection improvement projects beginning on SR 9 in Snohomish County

By Kris Olsen

Drivers who use State Route 9 through Marysville or Lake Stevens will see the beginnings of two new projects to improve traffic flow and safety.

At the intersection of SR 9 and 32nd Street S.E., our contractor will install new traffic signals this summer. Farther north at the intersection of SR 9 and 84th Street N.E. (Getchell Road), they will begin work on a new roundabout. The contractor started work Monday, May 19.

The intersection of SR 9 and 84th Street N.E. as it appears now
Traffic volumes are growing on SR 9, which is a vital commuter and freight corridor. As traffic volumes have increased, so have collisions and congestion. A roundabout and signals will help keep traffic moving and reduce the risk of collisions. Collisions and congestion often go hand in hand: four to ten minutes of traffic congestion can result from every minute a lane remains blocked.

The intersection of SR 9 and 84th Street N.E. after the roundabout is built
Here’s a closer look at each location and how the improvement will benefit drivers:

SR 9 and 32nd Street S.E. – traffic signals
  • The signals will control traffic in both directions of SR 9 and 32nd Street S.E., and include dedicated right- and left-hand turns lanes on SR 9.
  • The signals will be programmed to optimize traffic flow during peak periods.
  • Drivers at this intersection often have lengthy waits when trying to enter or exit SR 9.
  • Collisions can occur when drivers misjudge the speed of oncoming traffic.  From 2006 to 2010, there were 18 collisions at or near 32nd Street S.E. Of those, three were rear-end collisions and four involved drivers entering SR 9 from 32nd.
  • An intersection controlled by a traffic signal can reduce the risk of collision and improve traffic flow, particularly for drivers trying to enter or exit the highway.
SR 9 and 84th Street N.E. - roundabout
  • The roundabout will be large enough to accommodate trucks and buses.
  • A center truck apron or island allows the back wheels of large vehicles to ride up on it to easily negotiate the roundabout.
  • Drivers naturally slow in roundabouts. The few collisions that occur in roundabouts are typically minor and cause few injuries because of the low speeds.
  • Roundabouts encourage a continuous flow of traffic. They reduce the risk of collisions by approximately 30 percent and the risk of injury collisions by 75 percent.
    • Between 2007 – 2012, there were 43 reported collisions
      • 63 percent were rear end collisions
      • 16 percent were drivers entering SR 9 from 84th
      • 14 percent involved drivers heading in opposite directions
  • You can learn more about how roundabouts improve traffic, reduce congestion and collisions and how to drive through one on WSDOT’s roundabout information website.
What should drivers expect during construction?

Most of the work at both locations will occur weeknights from 9 p.m. to 5 a.m. Drivers can expect to see traffic reduced to a single lane on SR 9, 32nd and 84th. Flaggers will help direct traffic through the work zone. There will also be some daytime closures of right turn lanes, although turns will still be permitted.

There will be a full weekend closure of 32nd on the west side of the highway. The date for that isn’t scheduled yet, but it’s necessary to rebuild the approach to SR 9 and create a more level “landing” area for cars. That way, when the new signal is operating, drivers on 32nd won’t be waiting on a steep hill for the light to change.

When will the work be complete?

We anticipate the contractor will complete the work in fall 2014. 

1 comment:

Anonymous said...

How many rear endings will occur on northbound Hwy 9 because of this light?

How will the protected left signal speed up traffic flow?

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