Expanded Access to East County
The fifth phase of the Highway 4 Corridor Projects, the Hillcrest Avenue segment signified the highly-anticipated conclusion of construction on the main project corridor, ending in the city of Antioch. Additionally, the lane openings at Hillcrest Avenue marked a significant milestone: the official opening of all westbound highway lanes for the Highway 4 Corridor Projects.
The Hillcrest Avenue segment also required the most detailed construction work for the new BART station, including construction of a maintenance tunnel, the median platform foundation, the pedestrian overcrossing, and the entry house. A unique 145-foot-long and 13-foot-wide overcrossing was constructed to ensure the safe passage of pedestrians over the expanded four-lane westbound side of Highway 4 to the future BART platform at Hillcrest Avenue. Usage of a larger-than-life crane, as captured in the images above, was required to lift the platform into place — indeed a monumental sight to behold.
To bring regional connectivity further out into East County at a lower cost, the BART extension is being constructed with a new kind of train for the system, one that is 60% less costly to build than traditional BART trains. Additionally, thanks to leading-edge technology to be installed along the corridor, transit riders will enjoy more seamless connections between bus and BART.
– Randy Iwasaki, Executive Director, Contra Costa Transportation Authority
Highlights





Key Enhancements
- Widened Highway 4 from two to four lanes including a High-Occupancy Vehicle lane in the eastbound and westbound directions
- Reconstructed the Hillcrest Avenue Interchange to provide additional local street capacity, upgraded signalized intersections, an additional westbound loop on-ramp, and ramp metering capabilities
- Constructed the BART Pedestrian Overcrossing, Station Platform, and Maintenance Tunnel at Hillcrest Avenue
- Widened Slatten Ranch Road to provide additional local street capacity and accommodate the future BART Station Parking Facilities
- Constructed auxiliary lanes in the eastbound and westbound directions of Highway 4