A public meeting on a toll lane expansion along Interstate 405 provided more details on the project being undertaken by the Washington State Department of Transportation.

The project would extend toll lanes in both directions between I-90 and their current endpoints around Southeast 8th Street in Bellevue, which stretch north along I-405 to Lynnwood. The expansion is part of an overarching plan to have toll lanes running from Lynnwood in the north, which connect to a toll lane on State Route 167 south to Puyallup. State and local officials met for an open house on April 17 at Bellevue City Hall to explain the expansion to the public.

Widening the highway and re-configuring lanes to create two toll lanes in each direction through Bellevue is expected to cost $1.22 billion with construction beginning in 2019 and stretching through 2024. The DOT would upgrade interchanges and bridges along I-405 to facilitate an anticipated increase in traffic. By 2025, the state expects 255,000 vehicles to use the stretch of interstate daily, an increase of roughly 50,000.

One of the major projects will be building out four miles of trail on the Eastside Rail Corridor in conjunction with King County. The trail does not currently connect across I-405 after the Wilburton Rail tunnel was removed some years ago. When it was removed the state promised to reconnect the trail in the future and a new path, which will be fulfilled with this project. Roughly 2.5 miles of the trail which runs from Renton to Redmond will be paved.

All projects are funded through Connecting Washington and toll lane revenue, which has been generated since paid lanes opened on I-405 in 2015. Nearly 29 million trips on the toll lanes were logged in the first two years of operation and has generated roughly $29 million in revenue, of which $11.5 million has been reinvested. Tolls are in effect from 5 a.m. to 7 p.m. on weekdays, with off-hours and weekends free following push back from the public.

According to state statistics, drivers traveling south from Lynnwood to Bellevue saved 11 minutes and northbound drivers shaved off 13 minutes on average using the toll lanes. Speeds have been improved too, though they still don’t meet the DOT’s own performance guidelines. These stipulate vehicles must be able to drive at a speed of 45 mph or more for at least 90 percent of travel time during rush hours. Before the toll lanes were implemented I-405 was only hitting this goal 56 percent of the time, which has climbed to 85 percent following the lanes coming on line.

The DOT maintains that the management of stormwater runoff would be improved with the expansion since additional piping and inlets would be created to catch more water. Additionally, stormwater processing plants would be upgraded.

The project would add 2.7 new acres of pavement to the existing 104.4 acres in the project area, but the state says the water retention technology would result in lower contamination levels. Less than one acre of wetland would be destroyed along with two acres of vegetation, which would be mitigated elsewhere in Bellevue.

A public comment period is open until May 2 and state residents can weigh in by email at i405comments@wsdot.wa.gov.