Tentative deal reached on I-90 bridge light rail

Under a tentative deal reached Thursday, light-rail trains will take over the express lanes of the Interstate 90 floating bridge, in return for Sound Transit spending $153 million to create replacement lanes for buses and carpools.

The deal between Sound Transit and the Washington State Department of Transportation (DOT) improves the odds that Link light-rail service between Seattle and Bellevue can begin in 10 years as promised.

A rail corridor crossing Lake Washington was approved by voters as part of a 2008 ballot measure that raised sales taxes to build tracks north, east and south of Seattle.

The I-90 express lanes carry buses, carpools and Mercer Island drivers west in the morning and east in the evening. Once rail construction starts in 2015, motor vehicles will be displaced. Carpool lanes in the outer roadways — one each direction — must be ready before Sound Transit can occupy the express lanes.

By taking on more of the burden to build the carpool lanes, instead of waiting for state money, Sound Transit keeps its momentum. The DOT contributed $45 million to the carpool-lane project earlier, but lawmakers had postponed their next contribution until 2020, said Transportation Secretary Paula Hammond. Part of the project is already done: The westbound lane from Bellevue to mid-Mercer Island.

In a few months, the transit board will vote on a detailed agreement based on Thursday's deal.

Meanwhile, the state Supreme Court this year will consider a lawsuit by opponents, who argue the highway lanes — funded mainly by gas taxes — cannot be used for light rail. Opponents include Bellevue Square developer Kemper Freeman and former state Sen. Jim Horn of Mercer Island.

"I'm very sensitive to the fact a Supreme Court case is hanging out there," and it could jeopardize any deal, Hammond said.

Sound Transit says that past agreements among federal, state and local governments earmarked the center lanes for high-capacity transit someday.

The carpool lanes will provide two-way bus and carpool access 24 hours a day, Hammond said, unlike the express lanes now that go only in one direction. On the other hand, using the express lanes for light rail makes it impossible to add vehicle lanes in the future.

The state accepted $153 million as a fair price for the express lanes, in part because a study used by the state and Sound Transit determined the lanes were worth about $70 million. In addition, the state calculated its cost to build the lanes at $69 million.

However, Horn said DOT should be using a replacement cost of billions for the two freeway lanes. And some lawmakers had hoped to get $700 million or more from Sound Transit, to boost the highway fund, Hammond said.

"It's not nearly what I thought we were going to get," she said of the $153 million. But lawyers advised her the center lanes were intended for transit.

Mike Lindblom: 206-515-5631 or mlindblom@seattletimes.com