The Mid-Coast Trolley Extension was identified as a high-priority project by SANDAG and is part of the TransNet Early Action Program.
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 is provided by TransNet, the San Diego region’s voter-approved half-cent sales tax for transportation improvements. TransNet also provided operating funds for the project through the year 2048.
The project's budget is approximately $2.17 billion, including financing costs.
Pre-construction activities – consisting of the relocation of utilities out of the project alignment – began in early 2016, and primary construction activities began in October 2016. 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 early 2022.