WALNUT CREEK, Calif. – The California Transportation Commission (CTC) has approved $58 million in Trade Corridor Enhancement Program (TCEP) funding for the next phase of the Interstate 680/State Route 4 Interchange Improvement Project, a long‑awaited upgrade that will untangle one of Contra Costa County’s most persistent traffic chokepoints.
The new state dollars will be paired with approximately $160 million in Regional Measure 3 and Contra Costa’s Measure J transportation half-cent sales tax, enabling the Contra Costa Transportation Authority (CCTA) to begin construction next year.
“CCTA wants to express our deep appreciation to CTC staff and commissioners for funding this important project,” said Tim Haile, Executive Director of CCTA. “This interchange is a critical bottleneck in Contra Costa County, and the project will enhance safety, reduce congestion, and improve operating efficiencies for all users — including the freight movement that keeps our economy moving.”
Aaron Meadows, Chair of the CCTA Board of Commissioners, added, “We are investing in the quality of life for Contra Costa residents: shorter commutes, safer roads, and cleaner air, while strengthening a corridor that links the Bay Area’s ports, airports, and job centers.”
PROJECT DELIVERS SAFETY AND EFFICIENCY BENEFITS
State Route 4 is the primary east‑west link connecting Antioch, Bay Point, Pittsburg, and Brentwood with central Contra Costa County and the wider Bay Area, while Interstate 680 serves as the north‑south backbone through the county. The existing interchange forces drivers into a short, hazardous weave movement that contributes to collisions and backups.
The forthcoming improvements will:
- Construct an elevated ramp that carry traffic directly between southbound I-680 and eastbound SR-4 to replace the existing tight loop ramp that currently causes the weave conflict.
- Extend the connector ramp from eastbound SR-4 to southbound I-680 to eliminate the weave from the Muir Road on-ramp.
- Add modern ramp‑metering system on the new connector to smooth merging onto the freeway
- And remove the tight loop ramp that currently causes the double‑weave conflict.
Together, these upgrades will reduce travel times, boost safety, and cut greenhouse‑gas emissions by smoothing traffic flow and reducing idling. Final design for this phase is nearing completion, with construction slated to begin next year and wrap up by the end of 2028.
ABOUT THE TRADE CORRIDOR ENHANCEMENT PROGRAM
The TCEP directs freight‑focused state and federal dollars to projects that improve the movement of goods on key corridors, enhancing California’s economic competitiveness while reducing environmental impacts.
ABOUT CCTA:
The Contra Costa Transportation Authority (CCTA) is dedicated to enhancing transit efficiency, safety, and sustainability throughout Contra Costa County. Through strategic partnerships, innovative projects, and community engagement, CCTA leads the way in advancing a modern, multimodal transportation network that meets the diverse needs of its county.
For additional information, visit www.ccta.net.
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