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I-605/I-5 Interchange Improvement Project

The Challenge

Interstate 605 (I-605, the San Gabriel River Freeway) and Interstate 5 (I-5, the Golden State Freeway) are important north-south routes in the freeway network of Southern California.  The junction of these two major freeways, at the borders of Downey and Santa Fe Springs, is one of the busiest and most congested interchanges in the Los Angeles area. Future growth in the local and commuting populations is expected to exacerbate this problem. For the benefit of residents, businesses, and travelers, it is important to address this issue now by making improvements at the interchange.

The Los Angeles County Metropolitan Transportation Authority (Metro) and the California Department of Transportation (Caltrans) District 7, in collaboration with the Gateway Cities Council of Governments (GCCOG), propose to modify and improve the interchange.  As part of the planning, Metro and its partners are committed to coordinating with other current and future area projects to minimize disruptions to local communities as much as possible. They will also consider early action projects that can be implemented quickly and easily to ease congestion as soon as possible.

The Project is currently in the Project Approval & Environmental Document phase, which is only for the study and environmental evaluation of the proposed alternatives.

The Project Area

The proposed project is located in the Los Angeles metropolitan area adjacent to the cities of Downey, Santa Fe Springs, Pico Rivera, and Norwalk, and the unincorporated area of West Whittier-Los Nietos.

I-605/I-5 Interchange Improvement Project


Project studies are being funded through local Measure R funds.  Metro will also pursue additional federal, state, and other sources for future phases of the project.

Project Alternatives for the I-605/I-5 Interchange Project


The Project’s goals include:

  • Enhance mobility and quality of life for the community
  • Improve public safety
  • Minimize disruptions during construction
  • Meet transportation needs while minimizing adjacent impacts as much as possible
  • Improve the roadway by:
  • Reconstructing the interchange
  • Capacity and operational enhancement with additional mixed flow, HOV, and/or auxiliary lanes
  • Adding other modifications that enhance the driving experience

There are several benefits for this Project:

  • I-605/I-5 interchange improvements will provide relief from excessive congestion, provide safer operations, and create a less-stressful commute for motorists.
  • Improvements from the project are expected to help alleviate future impacts of regional growth and freeway congestion.
  • Upgraded freeway operations increases mobility and lessens congestion resulting in improved air and noise pollution, providing a better quality of life in the adjacent cities.
  • Improvements to the I-605/I-5 interchange will provide context sensitive solutions that take into account the local communities rich heritages and histories.


Project Status and Environmental Process

The project is currently in the Project Approval & Environmental Document phase (PA/ED or the “environmental phase”).  Several alternatives were identified in the initial Project Study Report.  Environmental studies, technical studies, and design considerations are now being undertaken to further evaluate various project alternatives.  At the end of PA/ED, an Environmental Impact Report/Environmental Impact Statement (EIR/EIS) will be prepared and the preferred project alternative will be selected.  The EIR/EIS is a legal joint document required under the California Environmental Quality Act and the National Environmental Policy Act (CEQA/NEPA), respectively. It will include a comprehensive description of the project and proposed alternatives, evaluate the project’s effects on the environment, and inform decision-makers and the public of reasonable mitigations, if any, that could minimize or avoid adverse impacts.  A draft EIR/EIS will be publicly circulated for comment prior to completing the final environmental document.  PA/ED is anticipated to take about 48 months.

The environmental process addresses a variety of issues related to the natural environment and human community such as traffic, air quality, water quality, noise, visual, endangered species, climate change, construction, and cumulative impacts with other projects in the area.  For this Project, it is anticipated that, in addition to the standard studies, special attention will be paid to:

  • Impacts on neighboring properties, the San Gabriel River, and local recreational facilities
  • Visual aesthetics of the structures and landscaping
  • Hazardous waste
  • Cumulative impacts from the I-5 Corridor Project and local street projects
  • Temporary traffic impacts and noise levels during construction

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