Interstate 605 Corridor Improvement Project

i-605 cip interchanges

Interstate 605 Corridor Improvement Project

Alternatives Analysis and Environmental Services to Keep Southern California Moving

One of Southern California's few north-south freeways, Interstate 605 is a major thoroughfare for moving people, goods and services throughout the Los Angeles region. But the interstate has not seen any major system-wide improvements for nearly five decades, since its construction was completed in 1971.

The Los Angeles County Metropolitan Transportation Authority, commonly known as Metro, is planning and designing improvements throughout this 28-mile corridor. Developed with input from Caltrans, the Gateway Cities Council of Governments and the San Gabriel Valley Council of Governments, the I-605 CIP project will improve safety, mobility and connectivity throughout the region, with the addition of managed lanes, a freeway widening, and improvements to interchanges and intersections.

Since 2016, HDR has provided numerous engineering, planning and environmental services, including corridor alternatives analysis, multimodal planning, traffic impact studies, travel demand forecasting, geotechnical engineering, right of way cost estimation, environmental documentation, seismic investigation, bridge and roadway design, and more.

I-605 cip aerial

A Culture of Collaboration

The proposed freeway widening considered a variety of managed lane configurations, which include a combination of improvements, many of which extend beyond I-605. Additional improvements included system interchange direct connectors at I-605/I-105, I-605/I-10 and I-605/I-5 with auxiliary lanes, reconfiguration of interchanges, and modifications to local street access. The Environmental Document also includes improvements on the I-5, which were done in cooperation with another design team.

Cooperation and collaboration have been a mainstay of the project, which requires working with multiple governments and agencies. The project includes improvements to freeways and local roads throughout Los Angeles County as well as the cities of Norwalk, Downey, Santa Fe Springs, Pico Rivera, Whittier, Industry, South El Monte, El Monte and Baldwin Park.

Strong partnerships and working relationships have been key to keeping the project moving forward. Our team worked with Metro to develop a strategy for combined delivery of both I-605 corridor projects in partnership with Caltrans to expedite the completion of the environmental review process, demonstrating our ability to manage complex technical issues with multiple jurisdictional involvement. Regular meetings with Metro ahead of monthly project meetings with Caltrans have provided a proactive approach to identify any project concerns and stay on schedule.

i-605 cip freeway traffic

In-Depth Environmental Analysis

Planning such a large project in the middle of the most populous county in the U.S. requires a wide range of documentation and studies. To date, our experts have prepared the Natural Environment Study, Jurisdictional Delineation, Relocation Impact Study, Initial Site Assessment, Historic Property Survey Report, Archaeological Survey Report, Historic Resources Evaluation Report, Water Quality Assessment Report, Community Impact Assessment, Visual Impact Assessment, as well as Section 4(f) Evaluation in support of the Environmental Impact Report/Environmental Impact Statement for the I-605, SR 60 and I-10 portions of the project. The Draft EIR/EIS is expected to be released for public comment in 2021.

Working efficiently, the team delivered an alternatives analysis in less than three years. The effort included traffic analysis modeling at 158 signalized intersections. HDR’s bridge experts also prepared advanced planning studies for 61 bridge locations, which include new bridges, replacement of existing bridges and bridge widening. Caltrans approval for all of the advanced planning studies was achieved a year ahead of schedule.

The project’s environmental phase is expected to be completed in 2022 with the release of the Final EIR/EIS.

i-605 cip interchanges