This project improved safety and reduced traffic congestion by adding one new lane and two miles of truck bypass lanes in each direction, building a new I-15 mainline northbound connector to restore route continuity, and reducing operational deficiencies and functional problems related to weaving trucks. Work included extensive drainage structures, construction over three railroad tracks, and significant environmental permit requirements related to the Cajon Wash and a protected species—the Kangaroo Rat. 

The project team constructed nine new bridges, widened nine more, and built 19,793 LF of retaining walls (totaling over 317,000 square feet). The project also reconnected the historic Route 66 highway that was severed when the original interchange was constructed 40 years ago.

During procurement, the Atkinson team optimized the design to provide the best overall project for California Department of Transportation, the environment, the community, and corridor users. This allowed Atkinson to deliver the project more efficiently, safely, at a lower cost, and four months early. 

Our design and construction approach reduced the construction of bridges by 20 percent, reduced earthwork cuts by 10 percent, eliminated imported borrow fill material altogether, and minimized the required right-of-way by over 12 acres (saving eight private residences).

Our phasing/sequencing plan allowed us to complete the majority of the construction during the day offline behind concrete barrier. This significantly reduced impacts to I-15—a critical link in goods movement from the Ports of Los Angeles and Long Beach that—combined—are the busiest ports in the United States of America.