Interstate 680 / State Route 4 Interchange Improvements

The purpose of this project is to increase the capacity and safety of the Interstate 680/State Route 4 Interchange. The proposed project will provide congestion relief and improve traffic operations within the interchange area.

The State Route 4 East corridor serves as the only major east-west transportation link joining the communities of Antioch, Bay Point, Pittsburg and Brentwood with central Contra Costa County and the Bay Area.

The Interstate 680 corridor serves as the main artery through central Contra Costa County, connecting it with Solano County to the north and Alameda and Santa Clara counties to the south.

  • Download comprehensive fact sheet
  • Special Provisions 95% Submittal (Not for Bidding)
  • Environmental Commitments

  • Project Plans 1 (Not for Bidding)
  • Construction Estimate (Not for Bidding)
  • Supplemental Project Report 
  • Final Project Report