In February 2013, Southern California Association of Governments (SCAG) approved the Alternatives Analysis (AA) Study of the corridor that analyzed opportunities to connect Los Angeles and Orange Counties along a 34-mile long corridor from Union Station in LA County to the City of Santa Ana in Orange County. The AA study recommended Light Rail Transit (LRT) as the preferred transit mode and two northern alignment alternatives (West Bank 3 and East Bank) for further consideration.
In 2015, Metro conducted a Technical Refinement Study (TRS) building upon the analysis and recommendations from the SCAG AA with a focus on the LA County segment of the Pacific Electric Right-of-Way (ROW)/WSAB corridor. In September 2015, based upon the West Bank 3 alternative, four new northern alignment options were identified as part of the TRS:
- Option A: Pacific/Alameda
- Option B: Pacific/Vignes
- Option C: Alameda
- Option D: Alameda/Vignes
The TRS provided updated capital cost and ridership forecasts, as well analyzed specific challenges identified in the SCAG AA for the LA County segment. In April 2017, Metro released the Northern Alignment Options Screening Report, which analyzed the six alignment options for the northern portion of the project. Upoon review, the Metro Board of Directors approved carrying forward the four Northern Alignment Options identified in the TRS for environmental study and initiating the scoping process for this project.
Metro formally initiated the Draft EIS/EIR phase in summer 2017 with public scoping meetings held along the corridor. In March 2018, the Metro Board authorized further study of an additional four Northern Alignment options in response to comments received during the scoping period and ongoing technical analysis. These new options were presented to the community for input during the March and April Community Update Meetings. On May 24, 2018, the Metro Board selected two Northern Alignment options to be carried into the Draft EIS/EIR for further study:
- Option E: Alameda Underground
- Option G: Downtown Transit Core
The Gateway Cities Council of Governments (COG) , which represents 27 cities in Southeast Los Angeles County, developed a Strategic Transportation Plan (STP) that unified the vision for all elements of the transportation system, including the WSAB transit component. The STP developed local resources and builds on previous transportation studies to create an integrated transportation system for the 27 cities in the Gateway Cities Subregion. The STP enables individual cities to understand how their transportation plans and decisions impact neighboring cities and vice versa — how individual cities fit within the larger region.