By Bart Treece

The name of the game is to keep traffic moving safely. But when there are several construction and maintenance projects that need to get on the road, the job gets complicated.

There really isn’t a “good” time to close part of entire stretches of highway in a large metropolitan area. However, the work needs to get done. Much of it is important for maintaining and preserving our aging infrastructure, like replacing bridge expansion joints (pdf 937 kb) on I-5 or patching the deck of the Ship Canal Bridge. Ignoring these issues would eventually mean unscheduled emergency closures that could impact your regular route to work. We all saw how badly traffic was snarled when a damaged joint needed repairs ASAP last week. This is why we try to schedule these closures when it affects the least amount of people, at night if possible. Some projects need more time, such as when there’s concrete involved which needs time to cure before its strong enough to hold the weight of hundreds of thousands of vehicles. That leaves the weekend, when fewer folks hit the roads.

The white board where closures are initially coordinated with large Seattle events and holidays

Looking at only weekends, we try to avoid four during the summer: Memorial Day, Fourth of July, Seafair and Labor Day weekend. This adds up to a whole month without weekend closures because we know those are big travel times. We’re now left trying to juggle projects on competing corridors, such as SR 520 and I-90 or SR 99, I-5 and I-405. It doesn’t take a traffic engineer to know that closing lanes in the same direction on north/south or east/west routes at the same time would be a very bad thing. Also add into the mix that there are several events including Mariners, Sounders, Husky and Seahawks football game traffic we try to take into consideration. We can’t forget weather, which isn’t always predictable in the ‘Pugetopolis’ region. The threat of liquid sunshine can push a weather-sensitive project back to another weekend.

With projects on every major route planned this summer, there’s not that many weekends left. When possible, we try to combine work to avoid spreading project impacts further along than needed.

By guest blogger Bart Treece

A sky of blue, a sea of green and a river of red brake lights….OK… that’s not how it goes, but that’s what folks could be seeing this weekend, unless they plan ahead  for congestion.

Let me explain. There are so many things to do this weekend in Seattle, and sitting in traffic shouldn’t be one of them when you’d rather be cheering the Sounders on against Sporting KC, enjoying the Seattle Dog Show or watching the women of the Pac-12 battle it out on the hardwood. With so much happening it might be kind of tough to get to where you want to be on time without some preplanning.

What’s going on?

Our contractor crews will be closing all but one lane on the northbound I-5 collector-distributor, which runs parallel to the wider section of I-5 between I-90 and Madison Street. The collector-distributor or “C-D” as it’s known in traffic-talk, helps merge cars from I-90 to I-5 and downtown off- and on-ramps. Here’s some nifty animation that shows how vehicles will navigate through the work zone.

The closure is the fifth of nine in this part of I-5 to replace 26 worn and aging bridge expansion joints before they go bust, which would lead to flat tires, emergency closures and major headaches. It’s happened before, and it ain’t pretty.

Emergency repairs to a damaged expansion joint in Dec. 2013

Traffic tips

Plan your trips ahead of time and know before you go. Carpooling, taking transit, delaying or combining trips will help reduce congestion in the area for everyone. Use alternate routes. If you can, take the backdoor into downtown Seattle on SR 599 to SR 99. We often see free-flowing traffic on this under-utilized route during weekend closures ...just sayin’.

With heavy traffic expected on westbound I-90 into downtown, SR 520 might be a better cross-lake route. The I-90 express lanes will look good westbound, and will be open to all (both carpoolers and solo drivers) during times of high congestion (keep an eye on the highway signs). Sounders fans should expect some delays heading eastbound after the match, so hanging in Pioneer Square for an hour to let traffic settle down would be a good idea. To head north from SoDo, take SR 99 or use surface streets to access the Cherry Street on-ramp to I-5 or the 5th Avenue & Cherry ramp to I-5 express.

You can always see how traffic is or isn’t moving through the area on the Seattle Traffic page or with the WSDOT mobile app for iPhone and Android devices.

There’s really never a “good” time to tighten traffic, but we really appreciate your patience and understanding when we do have closures for construction. Knowing ahead of time and planning for congestion really helps keep people moving, and we appreciate everyone for chipping in.