In the San Francisco Bay Area, California, USA, it is used specifically to refer to any transportation infrastructure including highways, bridges, tunnel, and transit services that crosses the San Francisco Bay.
Facilities that are referred to as "Transbay" include:
- Transbay Transit Center
- San Francisco Transbay Terminal
- Transbay Tube: Bay Area Rapid Transit's undersea tunnel connecting Oakland and San Francisco
- AC Transit's Transbay bus services