I-680/State Route 4 Interchange Improvement Project
The Interstate 680/State Route 4 Interchange Improvement project will increase capacity and safety of the I680/SR4 Interchange. The SR4 east corridor serves as the only major east-west transportation link joining East County with Central and West Contra Costa County. The Interstate 680 corridor serves as the main artery through central Contra Costa County, and also serves to connect Contra Costa County with Solano County to the north and Alameda and Santa Clara Counties to the south.
The proposed project reconstructs the existing interchange to provide a three-level system of direct connectors and diagonal ramps. State Route 4 is also proposed to be widened between Morello Avenue and State Route 242. Construction phasing is anticipated dependent upon available funding and each phase of the project is designed as an independent segment.
Phase 1 involves construction of the northbound Interstate 680 to westbound State Route 4 connector.