Hours of delay occurred daily on the I-5 barrier-separated HOV system through the heart of Orange County.
The Orange County Transportation Authority (OCTA) realized the need to improve the 3-mile segment between bottlenecks at the SR 55 and SR 57 freeway-to-freeway interchanges, and therefore included a project to address this need in its Measure M2/OC Go sales tax measure. Through the project development process, it was ultimately determined that removing the barriers that separated the HOV lanes from the general-purpose lanes and adding a second HOV lane in each direction would offer the relief needed.
The complex design called for the two southbound HOV lanes to be constructed where the previous (single) northbound and southbound HOV lanes had been, while realigning the two northbound HOV lanes into an area previously taken by northbound general-purpose lanes. By constructing a long retaining wall under the abutment of the existing railroad bridge, space was created to accommodate all northbound general-purpose lanes. This eliminated all widening in the southbound direction, and also avoided the need for several nonstandard design features.
An extraordinary challenge for this project was the demolition of the Main Street HOV drop ramp bridge structure, which required full freeway closures. The demolition was ultimately completed during a single weekend freeway closure.
“The OCTA is delighted to be part of a team that is dedicated to the success of this project,” said Niall Barrett, P.E., Msc, OCTA Program Manager. “The careful and strategic planning, thoroughness, and proactiveness throughout all phases of the project delivery speaks volumes to every member of the team.”
In total, the project added nearly 6 lane miles of HOV lanes. The project helped speed up commutes in this corridor, which will be traveled by 400,000 vehicles daily by 2035. Additionally, with congestion eased in the HOV lanes, overall travel times were improved, and more use of the HOV lane network has been encouraged.
Project: I-5 High Occupancy Vehicle (HOV) Improvement Project between SR 55 and SR 57
Location: Santa Ana, California
Owners: Orange County Transportation Authority/California DOT
Designer: T.Y. Lin International
Contractor: OHL USA
Cost: $41.5 million
Length: 3 miles
Completion Date: August 31, 2020
