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I-605 Corridor Improvement Project

About the I-605 Corridor Improvement Project
The Interstate 605 (I-605, the San Gabriel River Freeway) is one of the busiest and most congested transportation corridors in Los Angeles County, specifically between Interstate 105 (I-105) and Interstate 10 (I-10). Growth in the region’s population, employment, as well as in goods movement, are expected to further pressure the existing traffic capacity and operations on I-605. To ease congestion and support future growth, operational, capacity and safety improvements are needed for residents, businesses, travelers, and interstate commerce.

Metro, in collaboration with Caltrans District District 7, the Gateway Cities Council of Governments (GCCOG) and the San Gabriel Valley Council of Governments (SGVCOG), is proposing improvements along I-605 between I-105 and I-10 as part of the I-605 Corridor Improvement project (project).

The project also proposes to include improvements to the following major interchanges: I-105, I-5, SR-60 and I-10. Improvements to I-605 will enhance free operations, improving chronic traffic problems on one of Southern California’s most congested freeways.

Project goals

  • Ease congestion/improve mobility and operations
  • Enhance regional connectivity and system efficiency
  • Improve safety and enhance trip experience

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


The I-605 serves as one of the few major north-south interstate freeways in the greater Los Angeles Area of Southern California, running roughly 27 miles from the coast in Seal Beach, at its most southerly point, to the foothills in Irwindale/Duarte in the north. The operational conditions along the project corridor are deteriorating. In order to improve local circulation and connectivity to interstate commerce, I-605 improvements are necessary.

The I-605 provides public transit access to the Metro C Line (Green) light-rail in Norwalk Station at I-105, Metro Express Bus Line 577 running between I-10 and I-105, and a primary connection to the I-10, serving westbound Metro J Line (Silver) riders at the El Monte station. Moreover, a number of Foothill Transit Commuter Express Lines run from the I-10 to SR-60 by way of the I-605.

Unfortunately, I-605 has gone without major system-wide improvements for roughly 50 years, since the construction of the first segment, Interstate 405 (I-405) to State Route 60 (SR-60), dating back to 1964 and the later portion completing construction in 1971.


Persistent congestion during AM/PM peak travel times is especially pronounced within the project limits. The project alternatives seek to improve overall circulation and safety. The I-605 project proposes improvements from approximately two miles south of the I-105 interchange to approximately two miles north of the I-10 Interchange; including enhancements to the SR 60, I-5, I-10 and I-105 interchanges.

A range of project alternatives have been developed. In general, all proposed build alternatives feature widening of the I-605 mainline freeway. Project alternatives include (see cross-sections, below):

  • Alternative 1 (No-Build): The No-Build Alternative proposes to maintain the existing configuration of I-605. Roadway maintenance and completion of currently approved projects will continue. Alternative 1 does not meet the goals of the project.
  • Alternative 2: Proposes the edition of one new mixed-flow lane on both the northbound and southbound I-605 mainline between I-5 and I-10, and the conversion of the existing HOV lane to an ExpressLane. The following additional peripheral improvements are also proposed with this build alternative:
    • A new general purpose/mixed-flow lane on westbound SR-60 and Hacienda Bl to the I-605/SR-60 interchange
    • A new general purpose/mixed-flow lane on eastbound SR-60 and the I-605/SR-60 system interchange to 7th Ave
    • A new HOV lane on northbound and southbound I-5 from Florence Av to Lakewood Bl
    • Auxiliary lanes where necessary to enhance freeway operations
    • Reconfiguration of interchanges and modifications to local arterial streets to enhance freeway access.
    • Three HOV or ExpressLane direct connectors from north I-605 to west I-105, south I-605 to west I-105, and north I-605 to west I-10 with reverse movement for each
  • Alternative 3: Proposes the addition of one new ExpressLane on northbound and southbound I-605 and the conversion of the existing HOV lane to create two ExpressLanes in each direction within the project limits. The additional peripheral improvements as listed in Alternative 2 are also proposed with this alternative.
  • Alternative 4: Proposes the addition of a second HOV Lane on northbound and southbound I-605 to create a two-lane HOV facility within project limits. The additional peripheral improvements as listed in Build Alternative 2 are also proposed with this alternative.

I-605 Alternatives


The project proposes work to on- and off-ramps, bridges, underpasses, and local connecting roadways which will greatly improve circulation on local streets and improve access to businesses, benefiting residents, travelers, commerce, and local communities. These include:

  • Improved average daily travel times
  • Safer travel conditions and improved traffic flow by redesigning and relocation of existing ramps and merge locations
  • Improvements to interchange on and off-ramp entrances and exits
  • New and upgraded local intersections to improve traffic flow and safety
  • Enhanced traffic signal synchronization
  • New and improved bicycle lanes on local streets along the corridor to increase connectivity to the San Gabriel River trail
  • Reduction of the length of pedestrian/bicycle crossings to improve public safety and minimize potential auto-related accidents
  • Enhanced pedestrian connections by adding new or upgrading existing sidewalks, pedestrian overcrossings and pedestrian undercrossings in compliance with Americans with Disability Act (ADA) standards
  • Improvement to equestrian crossings and enhance existing equestrian trails along the corridor
  • Upgraded and additional stormwater treatment facilities to improve water quality and reduce trash entering local rivers and streams
  • Enhanced freeway driving experience through application of a corridor-wide Aesthetic Master Plan, which provides consistent structural and landscape beautification treatments
  • Construction of more than 100 new and replaced freeway soundwalls within the limits of the project to alleviate the impacts of the freeway noise on the adjacent communities

Local Improvements by Jurisdiction
The project area includes nine cities and a number of county island communities. The table below outlines the range of additional local improvements proposed for each jurisdiction. See the project improvement map for reference.

Local improvements by jurisdiction

Public Involvement

The public has multiple opportunities for involvement during the environmental phase and is strongly encouraged to participate. A series of public meetings (see tab below) will be held in the study area to coincide with major project milestones. Public hearings will be held following circulation of the draft environmental documents. Comments and questions can be submitted at the meetings, submitted via regular US mail, or shared by phone at 213-922-4091. Interested parties are also encouraged to stay connected by signing up to receive project notifications.


Environmental studies, technical studies, and design considerations are now being undertaken to further evaluate the feasibility of each project alternative. An Environmental Impact Report/Environmental Impact Statement (EIR/EIS) is being prepared to evaluate potential impacts of the project that could affect the quality of the human environment. At the end of the project phase, a Preferred 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. Upon completion, the document will:

  • Include a comprehensive description of the project and proposed alternatives,
  • Evaluate the project’s environmental effects, and
  • Inform decision-makers and the public of reasonable mitigations, if any, which could be employed to minimize or avoid adverse impacts.

A draft EIR/EIS will be publicly circulated for comment prior to completing the final EIR/EIS and selection of the Preferred Alternative. The environmental phase is scheduled to conclude in the spring of 2021.

Project Schedule/Environmental Timeline

I-605 Project schedule/environmental timeline

2020 Public Hearings

Public hearings are planned for summer 2020. Metro will continue to engage stakeholders throughout the study process and provide opportunities to:

  • Learn more about the overall project
  • Get details about the Technical Study currently underway
  • Ask questions
  • Share your thoughts
Past Meetings

2018 Community Meetings

February 6, 2018
Pico Rivera Senior Center, Pico Rivera

February 7, 2018
Lakeside Middle School, Norwalk

February 8, 2018
California Country Club, Whittier

2016 Scoping Meetings

October 24, 2016
Embassy Suites by Hilton, Downey

October 26, 2016
6:30 PM to 8:30 PM
Gus Velasco Neighborhood Center, Santa Fe Springs

October 27, 2016
Norwalk Assembly of God Church, Norwalk

November 1, 2016
Industry Hills Expo Center, Industry

November 2, 2016
South El Monte Senior Center, South El Monte

November 3, 2016
Palm Park Center, Whittier