Contractors
A conveyor transfers roadway materials to a roadbed.
By Irwin Rapoport CEG CORRESPONDENT
The California Department of Transportation’s (Caltrans) $54 million State Route 52 Pavement Improvement and Auxiliary Lane Project is bringing numerous improvements to a 3.9-mi. stretch of the highway near Convoy Street in San Diego.
Work by the joint venture of Coffman Specialties Inc. and Condon-Johnson & Associates began in March 2024. Project completion is anticipated by spring 2027.
The project is financed through the Federal Highway Trust Fund and the State Highway Fund.
The project is designed to resolve pavement issues near Convoy Street between Interstate 805 and State Route 163 and is adding an eastbound auxiliary lane from Interstate 15 to Santo Road. In addition, eight maintenance vehicle pull-
outs (MVP) will be installed to reduce highway work exposure during landscaping activities, and 13 existing metal beam guardrails will be upgraded to Midwest Guardrail Systems with steel posts.
“The settlement over the Old Miramar Landfill is causing uneven pavement conditions,” said Steve Welborn, Caltrans public affairs manager. “Construction crews have performed compaction grouting as ground improvement mitigation and will place an asphalt overlay, and that will level the uneven pavement and improve ride quality.
“This will provide comfort and safety for drivers and improve the structural performance of the pavement. Additionally, by implementing the subsurface ground improvement, projects will not be needed to correct the uneven pavement using frequent emergency overlay projects in the near future.”
see SR52 page 6
Compaction
LA Metro Breaks Ground On Bus G Line Improvements
The Los Angeles County Metropolitan Transportation Authority (Metro) celebrated on March 28, 2025, the groundbreaking of major construction for the $668 million Metro G (Orange) Line Improvements Project.
The series of Bus Rapid Transit (BRT) enhancements is projected to reduce average end-to-end bus travel times by 12 minutes or nearly 22 percent, allowing for fiveminute bus headways and eliminating the potential for motorist intrusions onto the busway.
Project improvements will enhance safety for buses, cars, pedestrians and cyclists alike on the dedicated BRT Line that travels between North Hollywood and Chatsworth. It will be built by Valley Transit Partners – a Joint Venture of Stacy and Witbeck Inc., Flatiron West and Modern Railway Systems.
Scheduled to be completed in 2027 in advance of the 2028 Olympic and Paralympic games, the project will advance Metro’s commitment to improve mobility and foster economic vitality in the San Fernando Valley. In the coming years, Metro
expects to build several Valley transit projects, including the East San Fernando Valley Light Rail Transit Project, the North San Fernando Transit Corridor Project, the North Hollywood to Pasadena Transit Corridor Project and the Sepulveda Transit Corridor Project.
“These are the most significant improvements Metro has made to this line in its nearly 20-year history,” said Janice Hahn, L.A. County supervisor and Metro board chair. “This work will make the G Line faster and safer in the short-term and brings us a step closer to our ultimate goal of converting the line to light rail.”
Over the next two years, the project will result in these improvements to the G Line:
Installation of four-quadrant gates at 13 busy Metro G Line intersections between North Hollywood and Van Nuys — the G Line’s busiest section. Enhanced safety features will include flashing lights and bells, raised medians and pedestrian/bicyclist crosswalk gates.
Implementation of more sophisticated transit signal priority and preemption in conjunction with the Los Angeles
Department of Transportation (LADOT). This implementation will extend the signal phase to favor Metro’s electric buses and give them the next green light in an intersection’s phasing cycle for faster service.
Construction of three bridges at Van Nuys Boulevard, Sepulveda Boulevard and Vesper Avenue to physically separate buses from cars, thus improving bus travel times and eliminating intersection bottlenecks on local streets.
Building a new aerial station on the Van Nuys Boulevard bridge, making room for a new street-level station for Metro’s new East San Fernando Valley Light Rail Transit Project, which will travel along Van Nuys Boulevard to connect the cities of Van Nuys, Panorama City, Arleta and Pacoima for greater regional mobility.
Resurfacing the adjacent bike path, painting new striping and installing new lighting, signage and fencing to improve safety and the user experience.
Adding bike lockers and bike parking at selected Metro G Line Stations to further encourage multimodal trips.
In late February, Metro began detouring
buses and cyclists off the bus right-of-way and adjacent bike path between Woodman and Sepulveda G Line Stations to facilitate construction work at Van Nuys Station. Demolition activities of the existing Van Nuys Station are expected to begin and will require that the station remain closed throughout the construction period.
The $668 million transit project is funded by Metro’s 2016 Measure M and Prop C voter-approved sales taxes, among others.
Approximately $64 million of the project cost has been made available by SB-1, the state’s gas tax and vehicle fee transportation funding program.
“These improvements to the G Line will save people time and facilitate better connections to our growing transit network in the San Fernando Valley,” said Metro CEO Stephanie Wiggins. “The G Line will also be an important part of our transit network for the 2028 Olympic and Paralympic Games, and we look forward to delivering this project in 2027, well before the Games begin.”
For details, visit metro.net/projects/ orangeline.
(All photos courtesy of LA Metro.)
An XTREME telehandler maneuvers during the March 28, 2025, groundbreaking.
An excavator tears aways asphalt at the March 28, 2025, groundbreaking ceremony for the $668 million Metro G (Orange) Line Improvements Project.
A worker takes a measurement at a future construction site.
Next Issue Closes May 7th
SR 52 Project Smooths Roadway, Adds Auxiliary Lane
The added lane will help with congestion.
“Eastbound I-15 to Santo Road is experiencing approximately 6,000 vehicles per hour during peak travel periods,” Welborn said. “The eastbound auxiliary lane is expecting to improve the operational flow of traffic as the I-15 connectors merge onto SR-52.”
The project’s been in the planning stages since 2017, although discussions began as early as 2014. It was launched in the state’s Systems Highway Operations Protection Program (SHOPP). The project was designed by Caltrans District 11 based on recommendations from the agency’s Office of Geotechnical Design South.
“It basically identified they would like to address 30 years of settling,” Welborn said.
“Segments of SR 52 are underlain by the old South Miramar Landfill, both east and west of Convoy Street from post mile 5.1 to 6.2,” said Roger Carlin, Caltrans engineer. “Continued settlement is due to biodegradation and consolidation of landfill materials. The compaction grouting design was based on the depths to the bottom of the landfill, inferred from past topographic maps, prior to the construction of SR-52.”
Caltrans has performed overlays of the lanes on several occasions above the settlement, as well as compacting operations.
“The nature of the subsurface landfill material within the project areas is such that future settlement, and the extent to which it should be expected, is far less predictable than typical site soil conditions,” Carlin said. “Prior to this project, overlay projects were being implemented every three or four years to address settlement. The plan is that this subsurface compaction grouting will provide stability for a time frame worthy of the state’s investment.”
“Subsurface investigation in the landfill material is difficult due to the environmental and health concerns with generating potentially hazardous waste and fumes during the drilling process,” he added.
As of March 20, the following project elements are complete: compaction grouting and construction of the eastbound auxiliary lane. Crews are working on rubberized hotmix asphalt work, drainage, electrical and striping improvements. Over the next year, efforts will focus on landscaping and project closeout.
The crews are dealing with several challenges.
“One is unknown existing landfill conditions for compaction grouting and unsuitable soil under the auxiliary lane,” said Jake Stelten, Caltrans project manager. “Early on, the project drew on the history of current conditions and best solutions and best practices. The design team worked with the joint venture team to develop the construction plan and techniques.”
The effort to reduce the uneven pavement settlement near Convoy Street between I-805 and SR 163 is making solid progress, with crews placing compaction grouting to slow the pavement settlement.
“The strategy is to support the pavement by pouring shafts of compaction grout down to soil that is more stable,” Stelten said. “The design utilizes a grid pattern for distributing the compaction grouting shafts. There are thousands of holes in the ground. Crews are drilling down to depths of 30 to 60 feet. Once the holes are dug, the grout is injected in. They do this over and over again until the stabilization system is created. The goal is to create a better grid system to support the pavement section.”
Equipment operators are using KLEMM and ABI drill rigs, APE vibratory hammers, Cemen Tech volumetric mixers, DSS and Belgrade cement silos, and Putzmeister (DEUTZ) and KLEIN concrete pumps.
Meantime, “The 1.3-mile eastbound auxiliary lane from I15 to Santo Road is being achieved by median widening. The previous lanes will shift towards the new median lane and is allowing what was the previous outside general-purpose lane to act as a new auxiliary lane,” Stelten said. “The median concrete barrier (Type K) will be removed and replaced with a high-tension cable barrier (HTCB) where feasible. The HTCB will be stained dark brown to reduce any visual impacts.”
The asphalt lane is based on 1.2 ft. Class 4 AC, 0.40 of cement-treated permeable base and 0.75 jointed plan concrete pavement. Standard construction techniques are being employed. Equipment used includes pavers, rollers, excavators, skid steers and loaders.
The eight maintenance vehicle pullouts are within the SR52/Convoy Street interchange and along the SR-52 main lanes near SR-163 and I-15. They are 12-ft. wide and 85-ft. long, including the tapers.
To minimize traffic impacts, Caltrans follows a traffic management plan that consolidates construction activities requiring closures, resulting in fewer lane, ramp and freeway closures for the public.
When similar work was performed in 2020, Caltrans was able to close the highway, which was doable based on reduced traffic because of the pandemic.
“We are now doing this with increased traffic, and we feel that eastbound and westbound weekend closures are the best method to minimize traffic impacts,” Carlin said. “The traffic plan is working.”
The highway will open to traffic in June, at which point the seven-month plant establishment phase will begin.
Typical days have 40 or more joint venture and subcontractor employees on site, which includes four drill rig crews operating simultaneously.
“This project does not require salvage or recycling of materials,” Welborn said. “However, the contractor can recycle materials if the material specifications are met for the reuse of materials.” CEG
(All photos courtesy of Caltrans.)
A new concrete lane is smoothed.
A new auxiliary lane required numerous heavy equipment vehicles for moving dirt. Workers clean concrete before compactor grout shafts are drilled.
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Newsom Pushes to Advance Plans for $20B Water Tunnel
California Gov. Gavin Newsom is pushing to lay the groundwork for a $20 billion water tunnel in the Sacramento-San Joaquin River Delta before his term expires, while state regulators are pondering whether to grant a key authorization, according to The Los Angeles Times.
The State Water Resources Control Board is holding a series of hearings on a Newsom administration petition to amend water rights permits. That would allow water flows to be diverted along the Sacramento River where the intakes of the 45-mi. tunnel would be built, the Times reported.
State plans call for construction starting in late 2029 with completion in 2042.
Both the Newsom administration and water agencies have questioned how the board’s officials are handling parts of the process, according to the Times.
Delta Conveyance Project supporters contend that the state needs to build new Delta infrastructure to protect the water supply from climate change and earthquake risks. Some Southern California water agencies are providing funding for planning work in support of the project.
Opponents, who include Northern California agencies, environmental advocates and native tribes, counter that the project would be too expensive and harm the environment, fish species and communities.
A new tunnel would create a second route to transport water to the state’s pumping facilities on the Delta’s south side. The aqueducts of the State Water Project there deliver water to 27 million people and 750,000 acres of farmland, the Times reported.
During a state Senate subcommittee hearing on April 3, 2025, Department of Water Resources Director Karla Nemeth said the existing system is “starting to really underperform,” and said the tunnel, if it existed now, could have captured more water during storms over the last three years.
State officials estimate that climate change could reduce average supplies available from the State Water Project by up to 23 percent by 2045.
Nemeth said the new tunnel would slow the decline and restore approximately 16 percent of that lost supply, according to the Times.
