Elon Musk says he will build a 240km/h train network underneath Los Angeles to bring an end to "soul-destroying traffic" in the city.
The technology billionaire behind Tesla and SpaceX promised the high-speed rail system of tunnels would cost passengers just US$1 ($1.45) a trip and would be constructed at a "cost that's not crazy".
Musk plans to launch a prototype train inside a 4.3km tunnel that his "Boring Company" wants to build on the western side of the city.
"We are going to figure out how to tunnel fast and safely," he told a community event in the city as he called for public support.
The project would see groups of about a dozen passengers travel in small pods through the tunnels on high-speed electric "skates".
