Thursday, June 22, 2017

I-405 peak-use shoulder lane is off to a positive start


By Victoria Miller

If you commute on northbound Interstate 405 between State Route 527 and I-5 in the afternoon, then you have most likely noticed or used the new peak-use shoulder lane. In late April, we used money collected from the I-405 express toll lanes to convert the existing shoulder to an additional travel lane during the afternoon commute, adding extra capacity to this congested stretch of roadway when it is most needed.

So far, we have succeeded in moving more vehicles through this area and decreasing travel times. It has been almost two months since the lane opened, so let’s explore the specific accomplishments of the project based on our first full month of performance data.

How many more vehicles are getting through?
Every weekday since opening, the peak-use shoulder lane has typically been open to traffic between 2 and 7 p.m. In the two months before the project was complete, an average of about 4,700 vehicles per hour were traveling on I-405 across all lanes just north of SR 527 between 4 and 5 p.m., the busiest time of the afternoon commute for that area.

With the addition of the shoulder lane, on average, more than 5,200 vehicles per hour are now traveling through this same section of the freeway at that time. More than 750 of those vehicles chose to use the peak-use shoulder lane. As a result, we are seeing less congestion in both the general purpose lanes and the express toll lanes, also resulting in lower average toll rates for an even more reliable trip in the express toll lanes during this time.

How much time are people saving on their commutes?
Between Bellevue and I-5:
In the two months before the peak-use shoulder lane opened, drivers commuting at the busiest times on the corridor were spending an average of about 38 minutes in traffic in the general purpose lanes. Thanks to the peak-use shoulder lane, drivers commuting at the same time in the general purpose lanes are saving on average between 10 and 15 minutes for this 17-mile trip.

Between SR 522 and I-5:
Commuters in the general purpose lanes were spending an average of about 20 minutes to drive about 7 miles. Thanks to the peak-use shoulder lane, the travel time for this trip has decreased by about half on average.

Is traffic flowing more smoothly?
For an example of how traffic has changed since the peak-use shoulder lane opened, check out the two flow maps below. These diagrams represent only a snapshot in time for the area between SR 522 and I-5, and we recognize that conditions can change daily, but these images help give a sense for how traffic has improved.

Thursday, June 15, 2017

Five consecutive weekends of lane closures to #ReviveI5

by Tom Pearce

Friday, June 16, marks the start of five consecutive weekends of pavement improvement work on northbound I-5 between SR 516 in SeaTac and the Southcenter area.

As we continue to #ReviveI5, our contractor crews will reduce northbound I-5 to two lanes during the following weekends:
  • June 16-19
  • June 23-26
  • June 30-July 3
  • July 7-10
  • July 14-17 

Expect major backups
Drivers should prepare for lengthy delays during each weekend. During the first weekend of work in June, we saw backups reach six miles at one point. Your best chance to avoid major delays is to plan ahead:
There are several alternate routes to use instead of northbound I-5.
Viva la differencé
This weekend we’ll do crack, seat and overlay work on the left lanes, with two lanes open on the right. We’ll also remove more than 300 feet of concrete panels at four separate locations and replace them with asphalt. Working on the right lanes means the on- and off-ramps at South 188th Street will be open. The SR 516 on-ramps and the South 200th Street on- and off-ramps to I-5 will be closed.

Crews need to remove sections of concrete panels the length of a football field, then replace them with asphalt, to create smooth transitions between the concrete and asphalt.
Making changes
We appreciate the feedback many of you shared with us after our first weekend of work. We received concerns about the lack of signs on some alternate routes, particularly near the South 200th Street/Military Road on- and off-ramps. We put out more signs during the first weekend, and we’ll have better signage throughout the rest of our work this summer.

Why weekends?
We hear that question every time we do a major project that disrupts the weekend. Our contractor crews are doing most of the work during overnight lane closures throughout the week.

It takes a couple of days to break the old concrete, compact it and repave asphalt over the top of it.

However, some of the work simply takes too long to do during overnight lane closures. Crack, seat and overlay work is a three-step process. An overnight shift doesn’t provide enough time to complete the needed steps.

It will be the same later this year and in the first half of 2018 when we replace expansion joints at Interurban Avenue and the Duwamish River – we need more than 50 straight hours to do that work.

We understand all of these lane closures are inconvenient. However, I-5 is the main artery of our region and we need to preserve it. We are confident that a little short-term pain will provide decades of smoother travel. Hang in there! We appreciate your patience!

Friday, June 2, 2017

Help researchers train computers to recognize road users, prevent collisions

by Ann Briggs

What if we could use technology to predict where vehicle collisions involving people who walk or bike will occur, then take steps to prevent them? Would you want to help? Well, now you can.

Volunteers are needed to help train computers to recognize objects and flag “near misses” at intersections. An example of a near-miss is when a driver nearly hits someone in a crosswalk.

Here’s how it works: your task is to view a short clip of a pre-recorded traffic scene, then label and track the movement of each person or vehicle within the screen. By doing so, the computer can begin to distinguish a person walking, biking, or using a wheelchair; a bus or car; then recognize patterns to identify near misses. Using the data from the video analytics, engineers could then take corrective actions to prevent future crashes.
Technology like heat mapping has the potential to help us improve road safety.


Fair warning to potential volunteers – until you get accustomed to using the labeling tools, it may take you several minutes to complete the task – plan on at least five minutes or longer per task at the start. Once you master the image tracking tools, your speed will likely increase. You can submit just one task, or complete as many as you’d like.

This work is part of a multi-city, multi-organizational partnership called Video Analytics Toward Vision Zero, a strategy to eliminate all traffic fatalities and serious injuries while increasing safety for all users of the roadway.
We need the public’s help to use our crowd-sourcing tool to analyze video and teach computers how to tell the difference between cars, buses, bikes and pedestrians.

Vehicle crashes involving pedestrians and bicyclists are on the rise in Washington state, as well as in other states. Fatal collisions involving bicyclists and pedestrians in Washington increased 6 percent from 100 in 2015 to 106 in 2016.

Why not give it a try? With your help, researchers can create a database that one day may save a life and make our roadways safer for everyone.

Thursday, June 1, 2017

Big changes come Monday, June 5 for I-90 drivers across Lake Washington

By Annie Johnson

If you travel I-90 between Seattle and Bellevue you're hopefully aware of our joint project with Sound Transit to add new HOV lanes to I-90 which will enable Sound Transit to build their East Link light rail extension across I-90 to Redmond. It's been a long process that started back in 2006 when we built a new westbound HOV lane between Bellevue Way and 80th Avenue SE on Mercer Island. In 2012 we opened the new HOV lane in the eastbound direction between Mercer Island and Bellevue.

Over the past 2.5 years we've been working on the final stretch of new HOV lanes between Mercer Island and Seattle. A lot of that work has been taking place off the roadway and mostly out of view of drivers but it will all come into view this weekend when we open the new HOV lanes and permanently close the express lanes.
A before and after look at I-90 across Lake Washington. Cones are in place in the new westbound
HOV lane. HOV lanes will open in both directions on Sunday, June 4.

What's the plan this weekend?
At 9 p.m. Friday, June 2, all eastbound I-90 traffic will be reduced to one lane. For most of the night eastbound traffic will remain in the express lanes while crews do one last night of testing systems in the tunnels, unveiling signs, and lane striping on the eastbound I-90 mainline. Early Saturday morning crews will switch the express lanes to the westbound direction one final time. Eastbound I-90 will remain reduced to one lane near Rainier Avenue while crews restripe the area near the eastbound entrance to the express lanes. This is an area crews can't reach when the express lanes are open eastbound so we'll be out there bright and early to do this striping before fully opening the eastbound roadway and the new HOV lane by 9 a.m. Saturday.

From 9 p.m. Saturday until 9 a.m. Sunday, westbound traffic will be reduced to one lane as we repeat Friday night's work but in the opposite direction. If you want to take one last drive in the I-90 express lanes for sentimental reasons I'd suggest doing so by 4 a.m. on Sunday. Around that time crews will begin to shift traffic back to the westbound mainline and permanently close the express lanes to vehicle traffic. However, westbound I-90 will remain reduced to one lane west of the Mount Baker Tunnel as crews restripe the area near the westbound exit from the express lanes. We expect to finish the work and reopen the westbound mainline by 9 a.m. Sunday.
Left: Crews have been working on re-striping I-90 across Lake Washington to put new HOV lanes in both directions in place before the express lanes are handed over to Sound Transit. Right: New signs will be unveiled this weekend as part of our project to introduce new HOV lanes on I-90 across Lake Washington while closing the express lanes for good.

What can I expect Monday morning?
How exactly these changes will impact your commute depends on a number of things including the time of day you travel and where you're going. You can find detailed information about the changes in an earlier blog. No matter what, you should definitely expect a period of adjustment. 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.

As we normally do, we'll be keeping an eye on things and doing our best to keep you informed of what's happening out there. Before you hit the road, take a minute to look at your commute with our WSDOT traffic app or check out the WSDOT traffic Twitter feed.
Upgrading systems in the I-90 tunnels has been a major component of our Two-Way Transit and HOV project.

What happens after this weekend?
Over the next few weeks our contractor crews will continue working to hand over the I-90 express lanes to Sound Transit as they gear up for light rail construction on I-90. Our work includes removing the existing overhead signs for the express lanes and placing barrier to permanently close the express lanes to traffic. There's always work to finish up even after a project opens to traffic so expect nighttime lane and ramp closures this summer. You can always find the latest information about I-90 lane and ramp closures in King County on our I-90 and SR 520 construction closures website.

Sound Transit's work on the bridge will begin with surveying, concrete work to prepare for future post-tensioning work at the East approach to the bridge, and relocating existing electrical equipment inside the bridge pontoons. For updates on Sound Transit's progress on this and other projects, visit The Platform blog.