Interstate 680 Auxiliary Lanes (Segment 2)

The I-680 freeway is a vital transportation corridor serving residents and businesses throughout Contra Costa County. Over the past four decades, traffic volumes have greatly increased along the I-680 corridor, placing substantial demands on the freeway and increasing congestion which affects local residents, businesses and the overall quality of life in Contra Costa County. In response to these increasing demands, the Contra Costa Transportation Authority (CCTA) has planned and implemented improvements along the I-680 corridor over the last decade. A key part of the I-680 corridor improvements is the construction of auxiliary lanes within the Town of Danville and portions of the City of San Ramon.

Due to funding limitations, the I-680 Auxiliary Lanes Project has been implemented in three segments. The final segment involved the construction of new auxiliary lanes in both the northbound and southbound directions of I-680 between Sycamore Valley Road and Crow Canyon Road. Construction began in early 2013 and was completed in July 2014.

The final step in the project involves planting ground cover, vines on the sound walls, and 3,800 trees and shrubs along both sides of I-680 between Sycamore Valley Road and Crow Canyon Road. Phase one planting was completed in November 2015. Phase 2 planting is scheduled to begin spring 2016 and is anticipated to be complete by early summer 2016. The project is funded by federal, state and local funds, as well as Measure C, the half cent transportation sales tax administered by CCTA.

  • Download comprehensive fact sheet
  • Retaining Wall and Sound Wall Plan
  • March 2013 Construction Update
  • July 2013 Construction Update
  • November 2013 Construction Update
  • Conceptual Landscape Plan
  • July 2014 Construction Update