Largest road tunnel by diameter
- Who
- Yerba Buena Island tunnel
- Where
- United States (San Francisco,)
- When
- 1936
The largest diameter road tunnel in the world is that blasted through Yerba Buena Island, San Francisco, California, USA. It is 24 m. (79 ft.) wide, 17 m. (56 ft.) high and 165 m. (541 ft.) long. More than 280,000 vehicles pass along its two decks each day.