Project Details

Primary Contractor and Managing JV Partner
California Department of Transportation
$420 million
September 2004
Start Date
September 2011
Completion Date

Building Interstate 15 Managed Lanes

The Interstate 15 Managed Lanes project is a new 20-mile section of High Occupancy Toll (HOT) lanes stretching from State Route 163 north to State Route 78 along Interstate 15 in San Diego, Calif. Flatiron executed this work under eight contracts totaling approximately $420 million.

The project is an adaptable, high-tech transportation facility designed to meet the diverse needs of local travelers, commuters and commerce in the San Diego region. Managed lanes were constructed within the existing median, providing direct “rapid” access by allowing buses to enter and exit the highway via dedicated on and off ramps. Highway authorities manage lanes by using a moveable median barrier to change the number of lanes in each direction, depending on traffic flow.

Construction along the I-15 corridor was divided into three segments, which were further divided into units. Flatiron was responsible for units 2-5 in the Middle Segment, Units 1 and 3 in the South Segment and Unit 1 in the North Segment.

Eight managed lane projects along Interstate 15

Lane widening, retaining wall and foundation construction, and roadway excavation

Adaptable, high-tech transportation facility with moveable median barriers and direct-access on- and off-ramps

North Segment (Centre City Parkway to SR-78): Flatiron upgraded a 2.6-mile portion of Interstate 15 at Unit 1 to contain four new HOV lanes. The project includes the widening of nine bridges, five earth retaining walls, five masonry block sound walls, storm drain and water system improvements, 110,000 cubic meters of exported material and 22,600 cubic meters of concrete pavement.

Middle Segment (SR-56 to Centre City Parkway): At Unit 2, Flatiron constructed 20 retaining walls, five new bridges and five direct access ramps. Unit 3 consists of a 2.5-mile stretch of managed lane construction and a bridge reconstruction over Lake Hodges. This project included eight post-tensioned box girder bridges, 9,000 cubic meters of retaining wall concrete, 32,000 cubic meters of PCC pavement, and 251,000 cubic meters of roadway excavation.

Flatiron constructed 1.5 miles of I-15 lanes from Poway Road to Carmel Mountain Road to complete Unit 4. Flatiron installed moveable barriers along a 1.5-mile stretch of managed lanes and used 13 different types of retaining walls at Unit 5, which ran from Via Rancho Parkway to Center City Parkway.

South Segment (SR-163 to SR-56): Unit 1 is a 4.5-mile segment of lanes stretching from Miramar to Escondido, where Flatiron is widening I-15 to accommodate managed lanes. At Unit 3, Flatiron widened two miles of interstate from Mira Mesa Boulevard to Route 56 and reconstructed the bridges over Poway and Mercy Roads. Flatiron produced all of the aggregate and structure backfill needed for the Poway bridge reconstruction directly on site.

Flatiron was the prime contractor for all contracts except for Units 2 and 3 along the Middle Segment, for which Flatiron was the managing joint venture partner.

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California Transportation Foundation
Project of the Year 2012
American Public Works Association, San Diego Imperial Chapter
Project of the Year 2011
California Transportation Foundation
Freeway Project of the Year 2009
Roads and Bridges Magazine
No. 4 Top 10 Roads 2009
"…a spirit of resolution and partnership has been fomented on this project...had it not been for the partnering spirit exemplified by Flatiron, obstacles would have risen that could have prevented a successful launching… please allow this letter to serve as a testimonial to the Flatiron spirit of partnering, characterized by foregoing short-term advantage or gain for a greater common good."
Dan M. Juarez, Resident Engineer, California Department of Transportation