Granite Construction expects to complete the first segment of the $779 million, three-part State Route 91 (between State Route 57 and State Route 55) Improvement Project in Orange County in late 2027.
The initiative, a partnership between the Orange County Transportation Authority (OCTA) and the California Department of Transportation (Caltrans), is upgrading a 6.6-mi. section of S.R. 91 to improve mobility and reduce weaving and merging between ramps and interchanges.
Orange County Transportation Authority photo
Segment 1 operations began in April 2025. Parsons Corp. designed the segment.
"The portion of S.R. 91 experiences congestion and traffic delays during peak travel periods due to local and regional traffic demand exceeding available capacity on the freeway, and demand is expected to increase," Eric Carpenter, an OCTA spokesperson, told Construction Equipment Guide. "In addition, weaving and short merging distances between successive ramps and the S.R. 57 and S.R. 55 connectors create several bottlenecks along westbound S.R. 91. Without improvements, the increased travel demand will result in increased travel time, delays and insufficient operating conditions along the freeway, ramps and areas of weaving.
"SR 91 is a vital link in Orange County's traffic network and, especially with more vehicles traveling to and from more affordable communities in the adjacent Riverside County, traffic is frequently backed up during weekday rush hours and on weekends," he added. "This is one of the major corridors that connects major ports and Orange County to the Inland Empire, the location of many commercial warehouses and manufacturing facilities that prompt significant truck traffic."
Taming Traffic
A 2020 traffic study projected local and regional traffic demand would increase along the project corridor from approximately 185,500 vehicles per day in 2014 to approximately 220,000 vehicles per day by 2050.
Orange County Transportation Authority photo
The project dates to 2008, when OCTA initiated a feasibility study to consider alternatives and design options that could improve mobility within the study area. The planning phase began in early 2013, while an environmental study began in January 2015. The design phase started in June 2020 and was completed in June 2024.
Local funds, $668 million, cover most of the project's financing. The state is contributing $92 million, with $19 million coming from federal funding.
The overall project includes S.R. 91 as it passes through Anaheim, Orange, Placentia, Fullerton and Yorba Linda.
Three-Part Project
Segment 1 ($141 million) focuses on the Lakeview Avenue Interchange and the immediate area.
Work includes adding a new signalized drop ramp from Lakeview Avenue that connects directly to the southbound S.R. 55 lanes; realigning the existing Lakeview on-ramp to feed only westbound S.R. 91; separating westbound S.R. 91 and southbound S.R. 55 traffic to streamline traffic movement further; and reconstructing the Lakeview bridge to feature standard-width lanes, shoulders and sidewalks in each direction to better accommodate vehicle, bicycle and pedestrian traffic.
Segment 3 ($257 million) focuses on the S.R. 91/S.R. 57 Interchange. The work, which commences in early 2026, is being done by OHLA.
Orange County Transportation Authority photo
Crews are reconstructing the La Palma Avenue bridge to include standard-width lanes, shoulders, sidewalks and bike lanes in both directions; adding a bypass ramp for the northbound S.R. 57 Orangethorpe Avenue off-ramp before S.R. 91, eliminating the need to merge across multiple lanes at the interchange; extending the auxiliary lane from southbound S.R. 57 to westbound S.R. 91 to the Raymond Avenue/East Street off-ramp to improve traffic flow; and improving the westbound S.R. 91 to the northbound and southbound S.R. 57 connectors.
That section should be completed in mid-2029.
A general contractor for Segment 2 ($381 million) hasn't been named. Crews will add a new eastbound general-purpose lane and reconstruct the Kraemer Boulevard and Tustin Avenue overcrossings to include standard lanes, shoulders and sidewalks in each direction.
The bridges and interchange work is impacting the S.R. 91/S.R. 55 Interchange, Lakeview Avenue Bridge, Tustin Avenue Bridge, Glassell Street/Kraemer Boulevard Bridge, La Palma Avenue Bridge, State College Boulevard Undercrossing and the S.R. 91/S.R. 57 Interchange.
"The primary challenge was designing geometry to allow sequencing the construction to maintain the existing general-purpose lanes and the tolled express lanes on S.R. 91," Carpenter said. "The roadway and structure geometry were adjusted to minimize the impact on traffic while maximizing the available space for construction. While some lane width reductions are necessary, the number of mainline and express lanes is maintained."
The roadway pavement has a lifespan of 40 years. The structure has a lifespan of approximately 75 years, with scheduled inspections and maintenance. The project was designed to meet projected traffic demand for approximately 20 years.
Precast Girders Used
The project is using spliced, precast girders.
Orange County Transportation Authority photo
"Due to the span lengths and vertical clearance limitations, precast girders were chosen," Carpenter said. "However, the span lengths were too long for continuous girders to be transported to the site, requiring the girders to be spliced in-place on the bridge bents. Also, we are using rapid-strength concrete in areas that are appropriate with applications to expedite curing time and open the ramps to the public as quickly as possible."
Crews have kept busy.
A Jan. 19 construction update noted that crews were pouring concrete and backfill columns and forming retaining walls and abutments to support the new Lakeview Avenue bridge.
For the sound walls, crews poured concrete and placed blocks.
Segment 1 began in mid-April 2025 with the placement of construction signs along the median of the S.R. 91 and vegetation removal (three weeks) along the westbound S.R. 91 on-ramp to Lakeview Avenue. The nighttime demolition of the center median of the Lakeview Avenue bridge followed.
Crews then demolished portions of the center median, performed striping work and removed overhead signage before demolishing the existing sound wall.
Staying On Schedule
Segment 1 is proceeding according to schedule.
"We are about one year into construction and, fortunately, the project has been going well and challenges we had are typical construction challenges with rain and field conditions — the kind of challenges that are built into the schedule and hard to fully predict until we are dealing with actual conditions in the field," Carpenter said. "We try to do as much work during non-rush hour times to maximize traffic flow during those hours. With less traffic on the roadways, it's often easier to focus on the tasks at hand without inconveniencing drivers."
Orange County Transportation Authority photo
The reconstructed Lakeview Ave. overcrossing will be 324 ft. long, with two to three southbound lanes (two southbound through lanes, one southbound right turn lane to southbound S.R. 55 and a southbound Class II bike lane) and four northbound lanes (two northbound through lanes, one northbound left turn lane to southbound S.R. 55 and one left turn lane to westbound S.R. 91). Each side has a bike lane and sidewalk.
"The bridge girders are precast, and the abutments and bents are being cast-in-place," said Carpenter. "The new structure is being constructed using precast girders with a cast-in-place deck to avoid the need for falsework over S.R. 91."
The existing structure will be demolished after the new one is completed.
"The plan is to demolish it over the course of four weekends and to remove the debris from the job site after each shift," Carpenter said, adding that crews will use excavators with hydraulic breakers, concrete crushers, diamond wire saws and skid steer loaders with demolition attachments and concrete pulverizers. The reconstruction effort involves excavation, foundation drilling, grading, building retaining and sound walls, grading, pouring of concrete pavement, HMA paving, placing RCP for the drainage system and installing traffic signals."
Equipment operators are using Cat loaders, Cat excavators and a variety of cranes.
The sound wall demolition and construction press forward.
"The debris from the demolition was removed from the adjacent area, stored in a stockpile area and was then processed," Carpenter said.
Demolition crews are using hydraulic shears, crushers, angle grinders, reciprocating saws and demolition hammers. The new 16-in.-by-8-in.-by-8-in. sound wall is being built with concrete masonry units delivered on an as-needed basis. The construction crews are using forklifts, power saws, mason twine, blocking chisels, wire brushes, margin trowels, stonemason's hammers and jointers.
The realigning of the westbound S.R. 91 on-ramp at Lakeview interchange also is proceeding.
"The roadway has rough-grade and fine-grade aspects," Carpenter said. "Crews are pouring LCB and JPCP. The profile graph includes new JPCP pavement, and crews are installing traffic delineation."
The addition of a new on-ramp from Lakeview connecting directly to S.R. 55 should take approximately seven months to complete.
Orange County Transportation Authority photo
"The MSE wall will be built for the drop ramp from Lakeview Ave bridge to WB S.R. 91 leading to SB S.R. 55," said Carpenter.
Cat excavators, Cat loaders and FMC cranes are helping with the operations.
Following the completion of the drop ramp, the separation of westbound S.R. 91 and southbound S.R. 55 traffic will start.
The work is putting the equipment of Granite and its subcontractors to the test.
"The equipment is maintained periodically to ensure that it can be used on an ongoing basis," Carpenter said. "The general contractor has an on-call mechanic. Regular maintenance ensures the equipment is consistently in good working order." CEG
