Politics & Government

More Auxiliary Lanes Coming to I-680

Interstate 680, between Sycamore Valley Road in Danville and Crow Canyon Road in San Ramon, is going to get a little wider.

Contra Costa Transportation Authority will begin a project this fall that will widen Interstate 680, both north and southbound, between Sycamore Valley Road in Danville and Crow Canyon Road in San Ramon with a 12-foot wide auxiliary lane.

The auxiliary lane allows a driver to get onto I-680 at, for example, Sycamore Valley Road, and stay in that lane until the drive hits the Crow Canyon Road exit. The same goes in the other direction from Crow Canyon to Sycamore Valley.

This lane will be 2.1 miles long between the two exits. The project is expected to begin this fall and completed by December 2014, according to a presentation by CCTA Director of Projects Susan Miller, at Danville's town council meeting last week.

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The 2.1-mile auxiliary lane is joining three mixed flow lanes and a carpool lane on that stretch of I-680.

This portion of the project is the last of three, Miller said. Segment one, from Diablo Road to Sycamore Valley Road, and three, from Crow Canyon Road to Bollinger Canyon Road, were completed in 2007.

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Danville Transportation Director Tia Williams said the $34 million project has been fully funded since the mid-2000s.

The funding looks like this:

  • Contra Costa Transportation Authority Measure C funds: $7.1 million
  • Tri-Valley Transportation Development Fees: $3.46 million
  • State/Local Partnership Program: $1 million
  • State Transportation Improvement Program: $19.45 million
  • Federal Interstate Maintenance Discretionary: $3.24 million

The lane widening will require crews to dig into the hillside to make room for the lanes.

The original sound walls will be removed during this project but Miller added that for the most part the new walls would be constructed before the old ones are removed. "There are a couple of areas that it's physically not possible to do that, they (the new and old walls) would be too close together," she said.

The sound walls will match the theme of the corridor, Miller said. Landscaping will do the same.

Miller added that when a project removes trees, it is required to replant them at a three to one ratio. The Sycamore to Crow Canyon project will remove 172 trees she said. Combined with the other two portions of the project, Miller added that the CCTA has more than exceeded the three to one ration. However, in this last portion of the project, spanning 2.25 acres of landscaping, 235 trees will be planted.


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