The I 680/Highway 4 Interchange projects will increase capacity and improve traffic safety for this major highway interchange. Highway 4 serves as the main east-west connection for Eastern Contra Costa County, while Interstate 680 serves as a major north-south connection for Solano, Contra Costa, and Alameda counties. As such, this interchange is a vital connection in Contra Costa County and must be able to adequately serve increased traffic in the years to come.
The project will be split into many phases and will include construction of a three-level interchange with two-lane direct connector ramps for the high-demand northbound to westbound and eastbound to southbound movements. The project will also widen Highway 4 from four to six lanes, eliminate the current eastbound lane drop on Highway 4 west of the Pacheco Boulevard interchange, and construct auxiliary lanes to the adjacent interchange ramps at Morello Avenue and Solano Way on Highway 4, and Pacheco Boulevard and Concord Avenue on Interstate 680.
This project finished its environmental studies and received clearance in November 2008. Feasibility studies are underway, and construction could begin in 2017.