Monday, May 22, 2017

Weekend-long lane reductions scheduled for northbound I-5 in SeaTac, Tukwila

By Tom Pearce

Our work to #ReviveI5 in South King County is about to ramp up! Since mid-April, crews on northbound I-5 between Kent and Tukwila have been replacing broken concrete panels, grinding the concrete to eliminate ruts, repairing concrete and much more - all while many of us are sleeping.

But some work requires more time than an overnight window can provide. Starting Friday, June 2, we'll begin the first of the project's 10 weekend-long lane reductions. We have eight weekends planned for 2017 and two in 2018. If the weather holds up, here's the six we've schedule so far:
  • June 2-5, 16-19, 23-26
  • June 30-July 3
  • July 7-10, 14-17

The cracker slowly rolls down southbound I-5, breaking the 50-year-old concrete panels.

During the six weekends already scheduled, our contractor will do crack-and-seat paving between State Route 516 in SeaTac and South 170th Street in Tukwila. For each of these weekends:
  • Crews will start reducing lanes at 8 p.m. Friday
  • By 10 p.m. Friday, northbound I-5 will be down to two lanes.
  • Between 11 p.m. and 4 a.m. on Friday and Sunday nights, northbound I-5 may be reduced to one lane.
  • By 5 a.m. Monday all lanes will reopen.
Why limit lanes on the weekend?
The simple answer is, there are some things we can't finish during an overnight lane closure. When we do crack-and-seat work, we have to remove a football-field length of concrete panels across two or three lanes at each end of the work zone and replace them with asphalt. You can't dig up that much concrete, then repave with asphalt in a single night.
During southbound work in 2016, crews use a roller to smooth out a section where new asphalt will be paved.

Besides replacing the concrete with asphalt, we have to use a cracking machine with a 12,000-pound blade to break a couple of miles of concrete. Crews then need to compress the pavement with a 35,000-pound roller. Next, we have to put asphalt over the top of that. We did this last year on southbound I-5 in the same area and it took all weekend to finish.

We're still scheduling the last two weekends in 2017. Those will probably be in late summer or fall, when we'll replace four expansion joints on the Duwamish River Bridge.

In the first half of 2018 we'll have two more weekends with northbound I-5 reduced to two lanes as we replace expansion joints on the Interurban Avenue overpass.
It takes a weekend to chip out old expansion joints, place new ones and pour the concrete.

We understand the inconvenience of all this work, but I-5 is more than 50 years old. If we want it to continue serving our families and businesses another 50 years, it needs major preservation work. The weekend-long lane closures allow us to complete parts of the project that need more time.

You can stay updated on work and traffic by checking our construction update page, following our Twitter account, checking our traffic map and downloading our mobile app.

Thanks for your patience!

Friday, May 19, 2017

Holiday travel charts a mix of facts, figures and common sense

by Barbara LaBoe

We know our holiday travel charts are popular – we get requests for them well before most holidays and drivers were disappointed last year when we were unable to produce Fourth of July forecasts.

Our Memorial Day Weekend charts are now out, but how do we make each year’s forecast? Good question.

Start with data, mix in analysis and common sense
The quick answer is a healthy mix of facts and figures with a dash of common sense. Staff in our Travel Data and Analysis office start out with historical traffic data from our roadway traffic sensors, then add in some analysis to improve the forecast.
We know holidays like Memorial Day have heavy traffic, but analysis and common
sense goes into predicting when the heaviest travel times will be.

An example? Last year there was a sudden mid-day dip in congestion on I-90 on the Saturday of Memorial Day weekend. That didn’t look right to our traffic engineers when they pulled up the numbers this spring, so they did some sleuthing. Turns out there was a large crash which temporarily stopped all traffic. Fewer vehicles moved past our sensors – but only because they couldn’t move, not because there were fewer drivers on the road. Using data from other years, we adjusted the charts to predict the steady congestion we expect to see this year. Without that adjustment, the straight numbers could lead people to think that several hours midday on Saturday will have relatively low congestion, when we expect exactly the opposite to take place.
We know holidays like Memorial Day have heavy traffic, but analysis and common
sense goes into predicting when the heaviest travel times will be.

Once the data is collected and analyzed, staff from our graphics and web teams format the charts so they’re ready to share with the public. We try to release the charts a week before major holidays to give people plenty of time to make plans.

How should I use the charts?
The charts are forecasts of the entire corridor – not an exact spot or milepost. They’re also tools to help in planning, not promises or guarantees. A crash or sudden, bad weather, for example, can change conditions and forecasts rapidly, so be sure you’re always prepared with supplies and check traffic conditions before heading out.

People returning to the west side on Memorial Day should travel
 before 9 a.m. or after 9 p.m. to avoid heaviest congestion.
Our traffic engineers suggest looking at the overall trend the charts show and then plan accordingly. The number of vehicles isn’t as important as the overall arch showing heavy congestion times. Is late afternoon and evening looking congested? Consider leaving earlier in the day or postponing travel until late evening or the next morning. If you have to travel during a peak time, recognize there will be lots of traffic and give yourself plenty of extra travel time so you’re not rushing or distracted by watching the clock.

Historically, our forecasts are pretty spot on. But ideally, our analysts hope that by sharing the predictions they’ll actually be proven “wrong.” If enough people adjust plans and travel during non-peak times, they say, it helps everyone travel more smoothly.

Are charts from previous years interchangeable?
We’re often asked why we can’t use last year’s charts for the current year. This is where the human factor and experience play a role. If the Fourth of July is on a Saturday, for example, we might see most people travel on late Thursday/early Friday and Sunday. If the holiday is on a Sunday, though, Friday night/Saturday morning and Monday afternoon become the most popular travel days. Those are things our engineers factor into their predictions.

A fair amount of traffic heads to Canada on the Saturday of
Memorial Day Weekend but traveling early or late will help.
Why don’t you have Seattle travel charts?
We get this question a lot. The answer is that Seattle is large enough that it doesn’t act like a typical traffic corridor because it has too many different ways to get around. Going north/south, for example, you can use I-5, I-405, SR 99 or a variety of city streets. That makes it hard to predict with good accuracy.

Our charts focus on the corridors where we see the most congestion without nearby alternative routes: I-5 from Olympia to Tacoma; I-90 over Snoqualmie Pass; US 2 between Stevens Pass and Leavenworth and I-5 near the Canadian border. In these cases, those routes are essentially the only viable options.

Why can’t you make the charts for every weekend, or my morning commute?
We’re happy the charts are useful enough for people to want them on a regular basis, but it takes a significant amount of time to do the analysis for each holiday – especially researching anomalies – and we don’t have the resources to do that on a regular basis.

Heading back from a trip to Eastern Washington on Memorial Day?
The roughest US 2 traffic will be from 10 a.m. to about 1 p.m.
If you want to do some comparison yourself you can get an idea of area traffic volumes using our Map Archives page, which lets you search by area, date and time of day. It won’t have analysis or as much historical data, but it can give you an idea of typical traffic at a given time.

What about Fourth of July this year?
Normally, we don’t create charts for holidays that fall midweek, including this year’s Fourth, which falls on a Tuesday. There are many more variables about when or if people choose to travel on those holidays. Last year, a glitch in our system prevented us from producing Fourth of July charts, which disappointed many.

So, would Fourth of July charts be helpful this year – with the caveat that the dates people may travel may not be as clear? Or should we stick to charts only on three- or four-day weekends? Leave your comments on this blog or email to: and we’ll use them as we make our decision.

Wednesday, May 17, 2017

Traffic change coming soon to southbound I-405 near SR 167 interchange

By Victoria Miller

Heads up, southbound Interstate 405 travelers near downtown Renton: Your driving experience will be a little different starting next week, especially if you rely on the ramp to southbound State Route 167.

As early as Saturday, May 20, we'll be making a long-term change to the way drivers access the off-ramps from southbound I-405 to Rainier Avenue South (Exit 2B) and southbound SR 167 (Exit 2A).

Right now, these two streams of traffic are separated by a barrier and travel in two parallel ramps. The far right lane takes travelers to Rainier Avenue South, and the second lane from the right takes travelers to southbound SR 167.
Drivers in Renton will find a new configuration off the off-ramp from
I-405 to Rainier Avenue South and SR 167 as early as this weekend.

Heading to southbound SR 167? Keep right
Under our new configuration, we'll combine those two exit lanes into a single lane. That means if you're traveling from southbound I-405 to southbound SR 167, you'll need to make sure you follow the new signs and get in the far right lane.

But rest assured, you'll still be able to get to both exits, as the lane will allow exits to both destinations. The barrier separating the two exit lanes will include an opening for those who wish to take Exit 2A.
The new lane configuration on the I-405 exit in Renton means drivers who want to
access Rainier Avenue South should stay right, and go left to get to SR 167.

Will this change affect traffic?
After we built an off-ramp to Talbot Road South several years ago, the volume of traffic using the Rainier Avenue South ramp dropped to around 200 to 300 vehicles per hour. We don't expect major backups as a result of this change, but there may be some minor slowdowns in the area as drivers adjust to the new configuration.

Why is this change happening?
Combining these two ramps while still allowing access to both exits will help crews move forward with the I-405/SR 167 Interchange Direct Connector project, which started construction last fall. We're in the process of building a new flyover ramp connecting the I-405 carpool lanes to the SR 167 high-occupancy toll lanes. Once open, the new flyover ramp will provide HOV drivers and transit a new option for traveling between I-405 and SR 167 while taking some pressure off the general-purpose ramps. We expect to open the flyover ramp to traffic in 2019.

You have probably already noticed that traffic has shifted lanes on northbound I-405 in the same area. This second traffic shift is to create a work zone to prepare for building the new flyover ramp in the center of I-405.

How long will this traffic shift be in place?
This change will be in place for at least several months as crews continue construction work for the Direct Connector.

This work is weather dependent so for the latest construction closure information, please visit our I-405 Construction Updates page and our King County Construction Updates page.

Monday, May 15, 2017

Ch-ch-ch-changes: Facing change on I-90 with new HOV lanes opening next month

By Annie Johnson

If you drive on I-90 between Seattle and Bellevue, you’ve probably noticed some pretty apparent changes to how the roadway looks over the past few weeks, including a big shift of the three existing lanes to the right side of the roadway. This shift is making way for the extension of the HOV lane from Mercer Island across the floating bridge to Seattle.

The new HOV lane will open the weekend of June 3. At the same time, the I-90 express lanes will permanently close to allow construction of Sound Transit's East Link light rail extension from Seattle to Redmond.

While our contractor is working hard to get ready to make this happen, it’s also time for you to start thinking about what these changes mean for your I-90 drive.

What to look for

Over the next few weeks, you can expect to see more work in the corridor as crews make the final preparations for the new HOV lanes and the closing of the I-90 express lanes. There’s approximately 14 miles of striping between I-5 and Bellevue Way that needs to be done before we can open the lanes, as well as the final testing of the new tunnel operations system, and other work like signing and irrigation systems. As you’re driving through the corridor be on your A game and pay close attention. The roadway will be changing and in transition for the next month or so.

You can also expect a period of adjustment when the new HOV lanes open and the express lanes close. This is a big change for everyone that uses I-90 across Lake Washington. It could take months for traffic to settle into its new routine.

I cross Lake Washington on I-90 all the time. What does this mean for me?

Let’s walk through the overall changes and then get into some details for specific areas.

The existing HOV lane currently starts or ends – depending on the direction you are traveling – near 80th Avenue SE on Mercer Island. After the weekend of June 3, this lane will extend all the way across the floating bridges to Rainier Avenue in Seattle. There will be one seamless HOV lane between Seattle and Issaquah that doesn’t depend on the direction of the express lanes.

The I-90 trail will remain open and unchanged for those who use it to bike, run or walk. Buses between Seattle and the Eastside will continue to use the same routes and stops they do today.

Rainier Avenue area
The new HOV lanes will start or end here depending on the direction you are traveling.
  • The ramps to and from the express lanes near the Mount Baker Tunnel will close.
  • The express lanes HOV ramps at 5th Avenue S in Seattle will become bus only.
  • The I-90/Rainier Freeway Station will remain open for bus riders heading between Seattle and the Eastside. It will continue to operate until September 2018 when Sound Transit begins construction on the Judkins Park Light Rail Station.

Mercer Island traffic
The express lanes ramps at 77th Avenue SE and Island Crest Way will close.
  • The westbound Island Crest Way on-ramp will become HOV only. You’ll need at least two people in your vehicle to use this ramp. Solo drivers will need to use 76th Avenue SE, East Mercer Way or West Mercer Way to access westbound I-90.
  • An eastbound HOV exit from the new HOV lane to Island Crest Way will open in mid-July. The existing right side exit will remain open.

East Channel Bridge area

  • The express lanes ramps near East Mercer Way will close.

These are obviously some major changes on a very busy corridor. The key will be studying up on what to expect, familiarizing yourself with the changes and then paying close attention when you’re on the highway. There will be a bit of a learning curve but eventually the new normal will kick in.

Friday, May 12, 2017

Don’t let construction delays in Cowlitz and Wahkiakum counties steal your sunshine

by Tamara Greenwell

After smashing several record rainfall totals since late last year, many of us are chomping at the bit to get out and enjoy the sun in our spectacular state. Once you get rolling, hitting the brakes can put a hitch in your giddy up unless you plan ahead.

It’s no coincidence that construction season and warmer weather go hand in hand in the Pacific Northwest.

Here’s why
Higher temperatures warm the roadway surface, which makes new pavement stronger and more durable. Resurfacing a highway in cool, wet conditions jeopardizes the quality of the final product. Waiting until we have long stretches of warm, dry weather means we get the best bang for our buck and ensures pavement repairs will last for years to come.

Last fall, resurfacing projects on State Routes 4, 411 and 432 in Cowlitz and Wahkiakum counties were put on hold due to cool, wet weather conditions, but with better weather in the forecast, construction resumes next week.

Know before you go!
While these projects will go a long way to preserve our transportation infrastructure, traffic delays are expected while crews are on the road. To minimize the impact of construction delays, a good portion of the work and lane reductions will take place overnight.

With almost 20 miles of resurfacing work to be done, it’s a good idea to plan ahead. Sign up to receive email traffic alerts or check current traffic conditions via our mobile app.

Project details
More than seven miles of SR 432 from SR 4 to 3rd Avenue in Kelso will get a fresh layer of pavement. Crews will also replace more than 60 broken and unstable concrete panels under the surface of the roadway to prevent additional deterioration.

A stretch of SR 432 in Kelso will get new pavement and concrete panels this summer.

Crews will resurface more than three miles of pavement on SR 411 between Longview and Castle Rock, along with intersection, crosswalk and striping enhancements along the corridor.

About three miles of pavement on SR 411 between Longview and Castle Rock will see pavement and lane marking enhancements during a summer project.

Almost nine miles of pavement on SR 4, between Kandoll Road and Ingalls Road through Cowlitz and Wahkiakum counties will get a new protective surface.

About nine miles of pavement on SR 4 through Cowlitz and Wahkiakum counties will get a new protective surface this summer.

The end result 
By the time fall comes around, we’ll all be restocked with our fair share of vitamin D and these resurfacing projects will provide a smoother ride as we roll into another wet winter.