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.
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
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.