TJPA was created in 2001 as a collaboration of Bay Area government and transportation agencies to design, build, operate, and maintain the new Transbay Transit Center, which will replace the existing Transbay Terminal that serves local, regional, and intercity bus transit. The Transbay Transit Center Project will replace the Transbay Terminal with a new multi-modal transportation center and centralize the region's transportation network by accommodating nine transportation systems under one roof. The project consists of three components:

• Replacing the outdated Transbay Terminal with a modern transit hub
• Extending the Caltrain rail line from its current terminus 1.3 miles and into the heart of the Financial District, including a provision for future high-speed rail (Caltrain Downtown Extension Program)
• Redeveloping the area surrounding the Transbay Transit Center

The Transbay Transit Center Project will construct a landmark multi-modal transit facility in downtown San Francisco, connecting the city’s urban core with 11 local, regional, and statewide transit systems. According to TJPA, mobility improvements constructed in this project will generate an estimated $380 million in annual travel time savings. The project will create a vibrant urban community by catalyzing nearby development, while reserving green space for a 5.4 acre rooftop park. The project is expected to facilitate the development of approximately 6 million square feet of commercial space and 4,500 new homes, over 1,300 of which will be affordable to low- and moderate-income households. Improvements are forecasted to create 125,000 jobs and $87 billion in gross regional product through 2030.