Friday, October 23, 2015

Tales from the I-405 ETLs: The case of the Aux Lane and the GP Lane.

By Amy Danberg

Express toll lanes on I-405 brought many changes for both the roadway and drivers.  Drivers have noticed some of these changes include repurposing an auxiliary lane in three locations to make them continuous through lanes.

We realize this is creating confusion so that’s what we’re here to address. This is a question that we’ve been answering throughout the planning of the I-405 express toll lanes. Did WSDOT take away a general purpose lane to create an express toll lane?

Before we get into the answer, I’d like to define a few key terms.
  • General purpose lane: A general purpose lane is a lane that continues for the length of the highway that everyone can use.
  • Auxiliary lane: An auxiliary lane used for merge and weaving. On I-405 it is an exit only lane that allows drivers to enter and exit the interstate. They don’t carry as much traffic as general purpose lanes. We'll call them merge and weave lanes to avoid confusion.
  • Express toll lane: Most of you are experts by now, but just in case  an express toll lane gives drivers the option to travel faster by paying a toll. Transit, vanpools, and carpools meeting the occupancy requirement can use the lane toll-free.
Now back to the question:

Did WSDOT take away a general purpose lane to create an express toll lane?
The number of general purpose lanes has not changed. There were three continuous through lanes before and there remain three continuous lanes after. We repurposed a stretch of the merge and weave lanes in three locations (see map to the right) between NE 85th Street and NE 124th Street, both north and southbound, and northbound SR 520 to NE 70th Street.  We understand that to a lot of you, these lanes seemed like general purpose lanes, and this change has caused some confusion. We took those merge and weave lanes and lengthened them to ensure we maintained three continuous general purpose lanes in both directions throughout the double express toll lane section, for a total of five continuous lanes.

The facts of the 17-mile express toll lane corridor
  • Total of 117 continuous lane miles from Bellevue to Lynnwood before.
  • Added 14 lane miles of new pavement north and south of the merge and weave lanes
  • Repurposed 6 miles of merge and weave lanes
    • NE 85th Street to NE 124th Street (both northbound and southbound)
    • SR 520 to NE 70th Street (northbound only)
  • Total of 137 continuous lane miles from Bellevue to Lynnwood after
This lane diagram shows how the lanes shifted between NE 85th Street and NE 124th Street:


Why did we repurpose the merge and weave lanes?
While these lanes carry traffic in between interchanges, they don’t carry as much traffic as general purpose lanes. Our analysis found that building an express toll lane reduced general purpose travel times by 10 minutes where building a new general purpose lane reduced travel times by 5 minutes; see the following graphic from the Transportation Discipline report.

When we built the new lane between NE 85th Street and NE 124th Street, we were also beginning to study the benefits of express toll lanes. Then in 2006, we began the Bellevue to Lynnwood Environmental Assessment which studied the effects of continuing to operate this lane as a regular lane or an express toll lane at a 3+ carpool requirement.



Did WSDOT comply with Federal requirements?
Moving Ahead for Progress in the 21st Century Act (MAP 21) is a funding and authorization bill to govern United States federal surface transportation spending. MAP 21 states that you cannot convert an existing general purpose lane to an express toll lane without a federal toll agreement. For the I-405 express toll lanes, we added new capacity to accommodate a second express toll lane, and reconfigured three stretches of merge and weave lanes on I-405 to operate as one, continuous general purpose lane  maintaining the same number of general purpose lanes. WSDOT sought clarification from the Federal Highway Administration in 2013 on whether a federal toll agreement was needed for the conversion of a weave and merge lane. FHWA does not consider merge and weave lanes to be general purpose lanes and responded that no toll agreement was necessary, therefore a memorandum of understanding was executed instead.

What outreach was conducted to communicate the repurposing of the merge and weave lanes?
Starting in 2006, we had a specific public process for the Bellevue to Lynnwood express toll lanes project. We held three public meetings for the environmental assessment, which included a public hearing in May 2011. Throughout the project planning we’ve provided over 200 briefings or presentations to community groups, neighborhoods, planning organizations, elected officials, and agencies.  We’ve also hosted eight additional public open houses. The results of the project planning work were an environmental assessment that found no significant impacts.  The environmental document that was publicly reviewed and commented on included the following alternatives:





What have we seen in those areas where the merge and weave lanes were repurposed?
Since express toll lanes opened, for the whole corridor we’ve seen that travel times have either improved or remained the same. At the same time, we’ve seen shifts on the timing and location of congestion points. While we’re seeing better performance overall, this helps explains why some drivers making shorter trips may be experiencing slower commutes. Some of the areas we’re seeing slowdowns include some of the portions where we’ve repurposed the merge and weave lanes including the northbound I-405 around the SR 520 merge area. Given the larger traffic volumes at SR 520 and other major interchanges, we accommodated these volumes by making longer access points into the express toll lanes longer at these locations. We’re also seeing slowdowns on southbound I-405 around NE 116th Street.  We’re monitoring closely how traffic adjusts and will continue to do so. Where we can make adjustments to improve traffic flow, we will make them. Over time, having five continuous lanes will provide a more efficient system by removing the bottleneck that was created at the end of merge and weave lanes.

As with any adjustment to a highway, it will take time for drivers to feel its full effects. We appreciate the questions we’ve received about the lanes. I-405 drivers are smart and ask questions—that’s a good thing. We want our drivers to be informed and savvy. We’re happy to share with you what we found to be the smartest choice and we thank you for your patience as we transition to this new and exciting system. 

13 comments:

Kevin B said...

Nice try WSDOT. You can't change the language now. ALL lanes were GP lanes including the HOV by your definition back in 2007. That was when you expanded 405 the proper way. You have lost all integrity among WA citizens and commuters. Your ignorance to the real issues is hitting a nerve with the Washington commuters. I would fire the whole bunch of ya.

zb said...

As I read this, you are arguing that you haven't taken away "general purpose" lanes with a semantic argument (in which you make the definitions). In practice, I think what this revision of 405 seems to have done -- using your own text and data -- might be to shorten drive times (at least temporarily) for longer distance commuters along I-405 (i.e. those going all the way from Bellevue to Everett or the equivalent) while slowing times for those who use shorter sections of I-405. That group, who are negatively impacted, includes those who may have sued the section of the road in the segments where you have taken away lanes (i.e. between NE 85th and NE 124th St), for example.

I'm listening to the possibility that some of the increased congestion in this northern corridor might be temporary, and improve as drivers learn the new patterns. But some of the change seems to be a prioritization of certain uses of the road over others (express lane through traffic over local commutes). I'm not sure if this change is by design -- but in any case, the value of these blogs depends on being honest about the effects, and not minimizing the real damage done to some commuters.

Cu Bong said...

-why ETLs is designed to use from Bellevue to Lynwood only ? but not apply to entire of SB and NB 405, that would make more sense when the longer of ETLs would make cars off the freeways faster , and make more reliable speed trip for the drivers who wants to travel from far from North to down from South
-you solved the nasty traffics were historical known from SR522 and SR520 but now created more traffic at both end due to unwisely designed exit/entry point with wasted spaces to use for the weaves lanes.
-RAM merge to 405 both direction of SR-522 and SR 520 are now backing up at 3:00PM and 7:00 AM ( frustration have seen , angrily drivers now more than before,
- SR-527 is now getting more heavier during rush hours because drivers avoided the expensive toll from I5 to -SR527
- Toll rate this morning was $4.50 if I enter to ETLs from SR-527 but realize I can hang around to get in the ETLs from SR-522 just 0.75 cents, your pricing wasn't smart and wasn't encourage drivers to use...I saved $3.75 this morning just because I patience enough to wait to enter to ETLs from SR-522
-we are suffering because the 2 bottlenecks I just mentioned above, would you please monitor it and fix asap

WSDOT said...
This comment has been removed by the author.
WSDOT said...

ZB - I can completely understand your concerns about prioritizing longer trips over shorter trips. Our plan when we built the lane between NE 85th and NE 124th was to always extend it to make it a through lane. By adding in express toll lanes we are ensuring that there is a reliable trip for everyone in the corridor when they need it. Population and job growth will continue to fill in the regular lanes, including the shorter interchange to interchange lanes, which means that lane would break down and no longer serve the shorter trips.

We are in no means trying to diminish the change commuters are adjusting to, especially in your area. The I-405 Master Plan does include one more lane in this area.

WSDOT said...

Cu Bong – Thank you for your questions. We’re happy to help clarify the issues you bring up. Let’s start with the extension of the I-405 Express Toll Lanes. We agree with you that congestion on I-405 needs a solution with a wider scope. That’s why WSDOT worked with I-405/SR 167 stakeholders to develop a vision for a 40-mile regional system of express toll lanes spanning from Auburn to Lynnwood. This vision is a part of the master plan for I-405 improvements focused on groups of projects that directly address the worst congestion choke points first, coordinating all transportation modes into a working system. As you mention, one of those areas in need of our attention is the stretch of I-405 between Renton and Bellevue. The I-405 Master Plan envisions adding two new lanes to I-405 between Bellevue and Renton. The I-405 Renton to Bellevue Express Toll Lanes project will add one of those lanes to create a dual-lane express toll lane system between NE 6th Street in Bellevue and SR 167 in Renton. This project was recently funded by the $16 billion transportation package. The project funded by the legislature will build one lane in both directions between Bellevue and Renton. This means that the second lane is still a part of the overall I-405 Master Plan’s vision and it will be added at a later date when project funding is available.

You also mention the designated access point weave lanes. While they do take up space, drivers still have the same amount of lanes to pass through the corridor. You may see drivers slowing down to enter or exit the express toll lanes. Weave lanes are designed to allow drivers enough time to safely adjust to the speed of the lanes they’re entering and find a window to safely merge. These lanes function very similarly to long highway on-ramps that allow drivers time to gauge and calculate a safe merge. In fact, designated areas to merge actually decrease congestion that would be caused by drivers quickly hopping in and out of the lanes.

Regarding the new back up times you observed, our traffic data has found that, over the month of October, we’re either maintaining or improving travel times in both directions in the general purpose lanes and significantly improving travel time in the express toll lanes. These travel time improvements are happening even when traffic volumes on I-405 were either the same or slightly higher in locations. But as you have observed, traffic choke points have shifted, which explains the congestion you’re seeing around SR 522 and SR 520. For now, we’ll continue to monitor the situation as we move to month two. When we can make adjustments to improve traffic flow we will make them.

Like you, we are watching local streets to get a good picture of the impacts express toll lanes on local streets. As of now, we are working closely with cities and jurisdictions to monitor traffic on their roadways and do not have any conclusive data. We hope to have travel times on some major arterials by the end of the November.

It seems that the other day, you experienced a perfect example of dynamic tolling. Since you’ve been using the express toll lanes, you’re probably familiar with how it works, but just in case, here’s a refresher: the toll rate varies between 75 cents and $10 based on how many drivers choose to use express toll lanes. The afternoon you experienced probably saw a large number of express toll lane users in between SR 572 and SR 522. Rates increase as more drivers choose the lanes to manage lane volume and keep traffic moving at 45 miles an hour or faster. Just as you saw, tolls are lowered when traffic is lighter to encourage drivers to move from regular lanes to express lanes.

Thank you for writing to us with your questions. We’re happy to help you understand how the express toll lanes work and how to make your trip as safe and efficient as possible.

Unknown said...

By removing the auxiliary lane from south bound i-405 through NE 124th area, you have caused the local traffic in the morning to back up considerably more. The on-ramp south bound from 124th backs up into the traffic light. This causes one direction of the traffic light to only let a few cars on at a time (east bound NE 124th from Juanita) because the other direction fills the on-ramp up completely. This causes traffic on NE 124th to cascade back several lights back. On the worst day just getting to the freeway now takes 45 minutes when it used to be 15 min on average. The average has now increased to 20 minutes. More importantly, it grid locks all of the surface streets regardless of the direction you are going.

The south bound 124th on-ramp was designed to regulate cars (alternating light) at a rate which worked when the entrance was a lane-add onto the freeway. Now that it is a merge, the on-ramp is broken. It needs to be updated to work like south bound 116th so as not to impact local streets.

Helena said...

WSDOT should be ashamed of itself for cheating the public and for its false propaganda and lies. This toll lane project is the dumbest project in transportation history. The idea that these toll lanes are improving people commutes are a complete joke. Everyone knows these tolls have made everyone's cummutes much much worse. We all would benefit if we were given our general purpose back. If the tolls were removed then everyone's cummute would improve tremendously and everyone knows this. Real Lanes For Real People!

WSDOT said...

ZB – WSDOT works hard to deliver honest and timely statistics on how the express toll lanes are functioning since their opening in late September. At the same time, the express toll lanes are very new to I-405 and it will take time to see more permanent results of the system. We appreciate your attention to our blog posts and will continue to provide updates to drivers.

eastside ron said...

Traffic is 20 minutes faster than last (2014) mostly due to the fact there is NO construction going on. We 405 commuters have spent the past 2 years trying to figure out where the lanes are to drive in and that changed almost weekly. Traffic is still the same or worse, but at least we know the lanes will be there in the future.
Traffic would move much faster with one toll lane 3 open lanes and a far right lane for entering and exiting the highway. The short entering roadways from 520 have jammed up 405 far worse than ever before even after rush hour traffic.

WSDOT said...

We realize this change may be frustrating for drivers used to making shorter trips between interchanges previously served by the auxiliary lanes, but we anticipate in the long-term this change will reduce congestion in both the general purpose and express toll lanes. As drivers adjust to the new system, I-405 will begin to function more efficiently. Additionally, our project team has been in close contact with local jurisdictions to determine where new congestion points exist and how they can be addressed.

WSDOT said...

Thanks for your feedback, Ron. The project team is looking into those problem areas along the corridor and evaluating what can be done to ease the flow of traffic. Express toll lanes are a solution that will move more vehicles faster than general purpose lanes would.

WSDOT said...

Unknown - Thank you for sharing your concerns about the Northeast 124th Street on-ramp to southbound I-405. As you have observed, the on-ramp now merges into a general purpose lane, because of that we adjusted the ramp meter when the express toll lane system opened. Cars are currently experiencing backups on the ramp because the meter is slowing the to rate at which cars can enter I-405 to optimize the overall flow of traffic. As traffic adjusts to the new lanes and improves, the speed of the meter will also quicken. As you suggested, the Northeast 124th Street ramp is using the same principles as Northeast 116th Street on-ramp, but the two roads experience different variables. If you’re in a hurry, I suggest trying the Northeast 128th Street Direct Access ramp that allows you to enter into the express toll lanes without having to merge.