Project Details

Lead JV Partner
California Department of Transportation
$550 million
February 2015
Start Date
July 2020
Completion Date

Building Interstate 5 North Coast

This CM/GC project is the largest for Caltrans in its pilot program. The project team, led by Flatiron, was chosen entirely on qualifications. The project encompasses three distinct work elements –highway, rail and lagoon — to deliver improved mobility while protecting coastal resources. It constructs one high occupancy vehicle (HOV) lane in each direction along 14 miles of I-5 from Lomas Santa Fe Drive in Solana Beach to State Route 78 in Oceanside. Other highway improvements include replacement of the MacKinnon Avenue Overcrossing, construction of a direct access ramp and multi-use facility at Manchester Avenue, replacement of the San Elijo and Bataquitos lagoon bridges, and construction of over 19,000 feet of sound walls on residential property and Caltrans right-of-way.

All highway and rail construction through the lagoons will be built to ultimate future capacity in this contract to minimize future lagoon construction impacts. The rail work involves bridge replacement and double tracking of the LOSSAN rail line over San Elijo Lagoon and Bataquitos Lagoon, signaling and communications work. The project also restores the San Elijo Lagoon and includes over 1 million cubic yards of lagoon dredging for increased tidal exchange.

As the lead joint venture partner, Flatiron is partnering with Caltrans’ design team to provide constructability expertise, innovative solutions and value engineering during final design, assist with environmental commitments and permits, as well as provide detailed cost and schedule estimates to finalize the construction budget and schedule for the project. This preconstruction process will result in multiple GMP construction agreements to build the project scope.

Complex staging of I-5 freeway construction with no full freeway closures

LOSSAN double tracking of 3.7 rail miles of ballasted track over San Elijo and Bataquitos lagoons.

Highway and rail work integrated with lagoon restoration/dredging