The existing State Route 160/Highway 4 interchange previously included only two of the four possible interchange movements. The State Route 160/Highway 4 Direct Connector Ramps project created a much-needed connection between the Senator John A. Nejedly (Antioch) Bridge and Highway 4 by constructing two new connector ramps, one connecting westbound Highway 4 to northbound State Route 160, and one connecting southbound State Route 160 to eastbound Highway 4. Additionally, this project eliminates the U-turn previously required at Hillcrest, removes through traffic on Oakley’s city streets, and improves access for Eastern Contra Costa County.
The project also added a 12-foot auxiliary lane to State Route 160 in both directions between the State Route 160/Highway 4 Interchange and the East 18th/Main Street Interchange, as well as new retaining walls. The southbound separation structure accommodates a future rail transit (BART) extension in the median of Highway 4.
Construction was contained within the existing right-of-way and progressed in phases. Initial substructure work involved installing cast-in-drilled-hole (CIDH) piles and driving steel shell piles for the ramp foundations, as well as constructing abutments. After temporary support structures (falsework) were erected, the bridge superstructure, or roadway, was constructed, then paved. New soundwalls were also installed as part of this project.
- 2.62 miles of new lane miles between Senator John A. Nejedly (Antioch) Bridge and Highway 4
- Additional auxiliary lane on State Route 160 in both directions » Two new soundwalls
- Retaining walls
- Contractor: RGW Construction, Inc.
- Construction cost: $33.5 million
- 18,500 cubic yards of concrete poured
- Start of work: Spring 2014
- Completion of work: February 2016
- Bay Area Toll Authority (BATA) Bridge Toll funds: $50 million