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.
State Route 4 is the primary east‑west link connecting Antioch, Bay Point, Pittsburg, and Brentwood with central Contra Costa County, including Concord and Martinez, 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.
If they were serious about relieving traffic, they’d end carpool lanes.
They do nothing to help emissions. They make driving more dangerous and cause congestion.
This was supposed to be reworked when they had the years long freeway work in that area not too long ago… so I wonder how many decades will it take this time and how much of the $58M will get siphoned off to other pet projects and how much the overrun will be … my guess is double the current estimate
I was thinking the same thing, what was all that work they did the last few years? I guess you need to be a CA politician to have repeated feedings at that taxpayer trough.
This project has been around for almost 20 years. Probably got shelved in 2008 when everything went to $hit economically. The design was there, why does it have to be redone?
No they won’t and will just waste tax dollar.
They were already supposed to do this. Then they “finished” the project with barely anything actually done.
They have been trying to do this since the early 90’s so let’s see if they get any traction this time
Fantastic! Long overdue and I really appreciate this work being done, thank you!