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Contra Loma Boulevard / L Street

ContraLoma_0040The Contra Loma Boulevard/L Street segment is the third construction segment along the corridor, between Somersville Road/Auto Center Dr. and Lone Tree Way/A Street. The project will expand the highway from four to eight lanes, including three mixed flow lanes and one High Occupancy Vehicle (HOV) lane, from just west of Contra Loma Boulevard//L Street to just west of Lone Tree Way/A Street. The project includes providing a full diamond interchange at Contra Loma Boulevard/L Street, a median wide enough to accommodate mass transit (BART) and eliminating the G Street on- and off-ramps.

Contra Loma Blvd / L Street


CC Myers, Inc.


$48.7 million


Construction began in March 2012 and the segment is expected to be open to traffic in fall 2015.

PROJECT UPDATE – November 2015

Milestone Activities:

  • Open all westbound lanes-week of November 1, 2015.
  • Open westbound off ramp and auxiliary lane-week of November 29, 2015. 

WB SR4 at the Completion of the Contra Loma Interchange

  • Open all eastbound lanes to Somersville Road and 2 eastbound lanes to A Street/Lone Tree Way- week of November, 22  2015.
  • Open an additional eastbound exit lane between Contra Loma Blvd/ L Street and A Street/ Lone Tree Way-week of December 6, 2015.

EB SR4 at the Completion of the Contra Loma Interchange 

Recently Completed Work:

  • Switched the eastbound SR4 traffic to the newly constructed interior lanes to allow the completion of the remaining highway improvements.
  • Switched the northbound and southbound Contra Loma Boulevard/ L Street traffic to the newly completed exterior lanes to allow the construction of the new median.
  • Switched the westbound traffic to the inside lanes to allow the completion of the sound wall on the new Contra Loma westbound bridge.
  • Completed the inside westbound lanes and eBART barrier.
  • Completed the PG&E overhead electrical relocations on Contra Loma Boulevard at Buchanan Road.
  • Completed the eBART bridge and the SR4 exterior bridges at Contra Loma/ L Street.
  • Completed the realignment of Claudia Court.
  • Completed the construction of the remaining interior lanes and  the  eBART  median.
  • Opened all lanes of Contra Loma Boulevard/L Street.

Upcoming Work:

Nighttime bridge demolition over Highway 4 - Photo courtesy of Karl Nielsen
  • Complete Construction of eBART median.
  • Complete Installation slope paving at the Contra Loma and G  Street bridges.
  • Install pavement delineation and signage for the completed portions of eastbound and westbound mainline and open added lanes to traffic.
  • Perform final project clean up and closeout work.