Staging for Success


Aerial view of Somersville Road/Auto Center Drive segment


Bridge Detail over Somersville Road


Crane at Somersville Road/Auto Center Drive


Construction of Bridge over Somersville Road


New Somersville Road undercrossing


Installing rebar for the Highway 4 bridge over Somersville Road

The second phase of the Highway 4 Corridor Projects, the Somersville Road / Auto Center Drive segment was completed in conjunction with the Loveridge Road segment to the west. To minimize disruption to traffic, the Contra Costa Transportation Authority scheduled work in highly orchestrated phases, and much of the demolition and reconstruction work for the bridges took place at nighttime during periods of lighter traffic.

At 3.26 miles, Somersville Road was the project’s shortest segment; however, it also encompassed the project’s most challenging interchange. This segment’s placement within the overall project demanded careful management of eight separate stages of construction activities alongside a busy local street. Construction required a 72-hour full weekend closure, a vast undertaking given that Somersville Road was – and is – one of the main business thoroughfares for Antioch and Pittsburg.

“These projects are about more than widening the highway. They are about improving mobility and access for Eastern Contra Costa County. We’re providing more transportation options and making it easier for commuters to get to work.”
– Ivan Ramirez, Construction Manager, Contra Costa Transportation Authority


timeline iconTimeline: March 2011 to December 2013
segment iconSegment: Somersville Road / Auto Center Drive to Contra Loma Boulevard / L Street
mileage iconNew lane miles added: 4.64
investment iconCapital investment: $43.2 million
contractor iconContractor: R&L Brosamer, Inc., Walnut Creek, CA

Key Enhancements

  • Widened Highway 4 from four to eight lanes, including a High-Occupancy Vehicle lane in the eastbound and westbound directions
  • Reconstructed the Somersville Road / Auto Center Drive Interchange to provide additional local street capacity, upgraded signalized intersections, and ramp metering capabilities
  • Constructed the BART median, including a BART bridge over Somersville / Auto Center Drive
  • Constructed auxiliary lanes in the eastbound and westbound directions of Highway 4