I-5 Oso Parkway Complete in Mission Viejo, California

Flatiron’s Interstate 5 Oso Parkway project in Orange County, California, is open to the public. This section of I-5 is the third most traveled roadway in the United States, carrying an average of 415,000 vehicles daily. 

Key achievements: 

• Constructed seven bridges in three locations  

• Installed 22 retaining walls, including soil nail, vertical and horizontal ground anchor and MSE walls.  

• Placed 43,000 cubic yards of concrete paving and 41,000 tons of HMA paving. 

• Upgraded all drainage and electrical systems. 

• Removed contaminated soils. 

Crews widened nearly three miles of I-5, adding extra general-purpose lanes in each direction and ramp auxiliary lanes to alleviate current and future transportation demands. Flatiron completed this project while working above active roadways and busy passenger and freight rail lines.