Traffic capacity on I-90 increased last week with the opening of a second westbound HOV lane between Bellevue and Mercer Island, along with new access ramps to serve those lanes from the two cities.

The changes allow Sound Transit to utilize the interstate’s center roadway for light rail between the Eastside and Seattle if voters approve the $18-billion Proposition 1 package in November.

A ribbon-cutting ceremony took place Oct. 9 to celebrate the additional westbound lane and the new access ramps at Bellevue Way Southeast and 80th Avenue Southeast on Mercer Island, all of which make up the first phase of a plan to increase HOV capacity operations and provide two-way transit along I-90.

King County Coucilmember Jane Hague, Congressman Dave Reichert, and Seattle Mayor Greg Nickels attended the event, as did several representatives from the Washington State Department of Transportation (WSDOT) and Sound Transit.

The new westbound HOV lane constructed along I-90 provides motorists with additional capacity throughout the day.

The existing center roadway along the corridor runs variably in the direction of peak traffic, serving high-occupancy vehicles. It will continue to operate that way until a final mass-transit plan is in place for the corridor.

“Having a 24-hour HOV option is another step in the direction of connectivity,” Hague said.

Future plans for expanding capacity along the interstate include adding an eastbound HOV lane between Bellevue and Mercer Island, and later constructing HOV lanes in both directions between Mercer Island and Seattle’s Rainier Avenue.

Nickels touted the completion of Phase One as proof that Seattle and Bellevue officials are bickering less these days over transportation issues.

He also thanked Hague for recognizing the need for “regional connections that work” during her time serving as a member of the King County Transportation Committee.

“Today is an important step,” he said. “This is part of a larger vision.”

The budget for this initial stage of work was $34 million, with funds coming from Sound Transit, WSDOT, and the Federal Transportation Administration.

Sound Transit has proposed using I-90’s center roadway for mass transit in a plan known as the East Link light rail project.

The plan is included in Proposition 1, which would increase the state sales tax by a half cent in an effort to expand light rail service to Everett, Federal Way, and Redmond, while increasing bus and commuter-rail service throughout the Puget Sound.

Transportation officials have estimated that these projects would take 15 years to complete.

Nickels announced during the Oct. 9 ribbon-cutting ceremony that an environmental impact statement for the East Link light rail project is expected by Dec. 5.

The timeline for that plan will become more certain at that time, he said.

Washington Secretary of Transportation Paula Hammond said the state would likely come up with another proposal for utilizing I-90’s center roadway for mass transit if voters defeat Proposition 1 in November.

“It’s a perfect facility for that,” she said.

The Oct. 9 ribbon-cutting ceremony took place on Mercer Island near 80th Avenue Southeast, near the city’s new HOV-lane access ramp.

Several nearby streets were lined with signs opposing Proposition 1.

Nickels cautioned voters against defeating that measure a second time, noting that there were consequences after the Forward Thrust initiatives of 1968 and 1970 suffered that same fate.

Federal funding for those projects amounted to nearly $900 million. The money eventually went toward rapid transit in Atlanta rather than the Puget Sound area.

King County Executive Ron Sims has opposed Proposition 1, even he supports the concept of light rail for the future.

He stated in a Seattle Times op-ed piece that the current plan is “long on future light rail and short on immediate congestion relief.”