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Public Transit

Mid-Coast Trolley Extension

The Mid-Coast Extension of the UC San Diego Blue Line Trolley extends service from Downtown San Diego to the University Community. The eleven-mile Trolley extension improves access to growing employment, education, medical, and residential areas in addition to serving major activity centers such as Old Town San Diego, Mission Bay, UC San Diego, and Westfield UTC. Construction for the project began in fall 2016, and the Trolley extension opened for revenue service on November 21, 2021, on time and on budget.

Watch a short video on the project’s history and grand opening celebration.

To learn more about the project and view images from the grand opening celebration, please visit or follow the Mid-Coast project on Twitter and Facebook.


Freeways and arterials in the Mid-Coast Corridor are generally congested, and traffic congestion is projected to increase more as the region grows. The population along the corridor is predicted to increase 19 percent by the year 2030, while employment is predicted to increase by 12 percent.

The Mid-Coast Trolley Extension expands transportation capacity in the corridor to accommodate existing and future travel demand, particularly for peak-period commute trips. The project provides an effective alternative to congested freeways and roadways for travelers, leading to fewer vehicle miles being traveled.

The University Community has developed as a major employment and high-density residential area, similar to Downtown San Diego. Although the University Community is considered San Diego’s second downtown and UC San Diego is one of the region’s largest trip generators, neither was directly served by regional transit. The Mid-Coast Trolley Extension now provides efficient transit connections to the University Community and UC San Diego, as well as frequent and reliable Trolley service throughout the corridor. Transportation models indicate that the new Trolley service will attract 20,000 new transit riders a day to the system.

The Trolley extension route begins just north of the Old Town Transit Center and travels in the existing railroad right-of-way alongside I-5 to Gilman Drive. It crosses to the west side of I-5 just south of Nobel Drive and continues to the UC San Diego campus before crossing back to the east side of I-5 near Voigt Drive to serve the UC San Diego east campus and Scripps Memorial Hospital. From there, the Trolley extension continues along the Genesee Avenue median to the UTC Transit Center (view map).

SANDAG worked with the communities along the corridor to refine and develop designs for each station. View early presentations made to corridor planning groups highlighting the design features of stations in the University Community, Pacific Beach, Clairemont, and Linda Vista.

Nine new stations were built at Tecolote Road, Clairemont Drive, Balboa Avenue, Nobel Drive, the VA Medical Center, UC San Diego west campus, UC San Diego east campus, Executive Drive, and the UTC Transit Center. View early station simulations.

The project connects corridor residents with other Trolley lines serving Mission Valley, East County, and South County. As an extension of the existing Metropolitan Transit System Blue Line Trolley, it offers a one-seat (no transfer) ride from the U.S./Mexico Border and communities south of Downtown San Diego all the way to the University Community. This new service enhances direct public access to other regional activity centers and improves travel options to employment, educational, medical, and retail centers for corridor residents, commuters, and visitors.

The Mid-Coast project’s completion is a significant step toward realizing the vision for SANDAG’s 2021 Regional Plan, which aims to address traffic congestion, social equity, and state and federal mandates to create a balanced transportation system that will serve our region for generations to come. The result will be a transportation system that is faster, fairer, and cleaner than ever before. You can explore the 2021 Regional Plan by visiting our website (English | Español).

Project Status

The Mid-Coast project was first introduced in SANDAG’s 1986 Regional Transportation Plan.

In fall 2014, the Mid-Coast Trolley Extension received its final environmental clearance from the SANDAG Board of Directors and the Federal Transit Administration (FTA).

In September 2016, the FTA signed a Full Funding Grant Agreement with SANDAG to provide the 50 percent federal funding match needed to begin construction in fall 2016. The other half of the funding was provided by TransNet, the San Diego region’s voter-approved half-cent sales tax for transportation improvements.

Pre-construction activities – consisting of the relocation of underground utilities out of the way of the project alignment – began in early 2016. Primary construction activities began in fall 2016 and construction reached its halfway point in spring 2019. The Mid-Coast Extension of the UC San Diego Blue Line Trolley opened for revenue service on November 21, 2021, on time and on budget. Crews are anticipated to complete final construction activities in 2022.

Clairemont Drive Trolley Station Parking

Transit parking for the Clairemont Drive Trolley Station is currently unavailable. Parking for this station will be provided as part of a private development at the northeast corner of Morena Boulevard and Ingulf Street, directly across from the Trolley station. Once completed, the parking area will include 150 spaces for transit users. SANDAG is exploring solutions to provide interim transit parking near the Clairemont Drive Trolley Station and is prioritizing parking for persons with disabilities. In the meantime, nearby transit parking is located at the Balboa Avenue Transit Center (1.2 miles north, on Morena Boulevard) and Tecolote Road Trolley Station (1.5 miles south, on Morena Boulevard).

Project Contractor

In May 2014, the SANDAG Board of Directors selected Mid-Coast Transit Constructors, a joint venture firm of Stacy & Witbeck, Inc., Skanska USA, and Herzog Contracting Corporation, to serve as the construction manager/general contractor for the project. Additionally, the project contracted with more than 320 disadvantaged business enterprises and other small businesses and issued payments totaling more than $365 million. Disadvantaged business enterprises and small businesses interesting in working on SANDAG projects can find more information here.

Stay Informed

To stay up to date on the project, you can:

Environmental Documents

Addendum to the Final Subsequent Environmental Impact Report for Proposed Work in Pepper Canyon - May 2018

Addendum to the Final Subsequent Environmental Impact Report for Project Refinements at the Nobel Drive Station - May 2018

Mid-Coast Corridor Transit Project Final SEIS/SEIR - October 2014

Notice of Availability of the Mid-Coast Corridor Transit Project Final SEIS/SEIR – October 2014 (English)

Notice of Availability (abridged) of the Mid-Coast Corridor Transit Project Final SEIS/SEIR – October 2014 (Spanish)

Mid-Coast Corridor Transit Project SEIS - Supplement to the SEIR - July 2014

Report only
Appendices A-C only

Draft SEIS/SEIR - May 2013
Notice of Availability: English | En Español - May 2013
Notice of Completion - May 2013
NEPA Scoping Report - October 2011
CEQA Scoping Report - July 2010

Final Comparative Evaluation of Alternatives Report

Table of Contents and Executive Summary
Chapter 1 Purpose and Need
Chapter 2 Process for Development and Screening of Alternatives
Chapter 3 Identification and Screening of Initial Alternatives
Chapter 4 Conceptual Alternatives Considered
Chapter 5 Analysis of Transportation, Environmental, Cost and Financial Considerations (pages 1 - 50)
Chapter 5 Continued (pages 51 - 102)
Chapter 6 Evaluation of Conceptual Alternatives
Chapter 7 Review and Selection of Alternatives for Scoping
Chapter 8 Public Outreach, Scoping Process, and Scoping Comments
Chapter 9 Recommended Locally Preferred Alternative and Alternatives for Evaluation in Draft SEIS/SEIR
Appendix A Conceptual Plans
Appendix B References


Mid-Coast Corridor Project
Balboa Extension and Nobel Drive COASTER Station

Volume I | Volume II


Mid-Coast Corridor
Alternative Analysis / Draft Environmental Impact Statement /
Draft Environmental Impact Report / Final Environmental Impact Statement

Cover | Executive Summary
Chapter 1 - Purpose and Need
Chapter 2 - Alternatives Considered
Chapter 3 - Affected Environment
Chapter 4 - Transportation Impacts
Chapter 5 - Environmental Consequences
Chapter 6 - Financial Analysis and Evaluation of Alternatives

Final Environmental Impact Report for the Mid-Coast Corridor

Project E-newsletter

July 2016 | April 2015 | November 2014 | October 2014 | October 2014 | August 2014 | July 2014 | June 2014 | Winter 2014 | November 2013 | May 2013 | Fall 2012 | Spring 2012 | Fall 2011Summer 2011 | December 2010 | August 2010 | July 2010 | June 2010 | May 2010 | April 2010 | March 2010 | February 2010 | December 2009/January 2010 | November 2009 | October 2009

Project Management

Ramon Ruelas, Mid-Coast Corridor Director
Phone: (619) 699-6940, Email:

Greg Gastelum, Project Development Program Manager
Phone: (619) 699-7378, Email:

Sharon Humphreys, SANDAG Director of Engineering and Construction
Phone: (619) 595-5350, Email:

Robyn Wapner, SANDAG Director of Communications
Phone: (619) 699-1994, Email:

For media inquiries, please contact the SANDAG Public Information Office at (619) 699-1950 or