Elon Musk shares first-look into The Boring Company's 'disturbingly long' tunnel

The company claims tunneling costs must be reduced at least 10-fold for a network of crisscrossing tunnels to be feasible. It's not clear what the current costs for The Boring Company tunnels might be, but the firm claims to have engineered a cheaper way through smaller diameters and 24/7 boring.

The system can also transport individual cars, but will prioritize pedestrians and cyclists, its website says, at speeds up to 150 miles per hour.

The tunnel walls are equipped with vertical "curbs" to keep the skates in line as they travel, and a walkway for maintenance and emergency exits.

Speaking with Recode, Musk said eventually there could be 100 levels of tunnels below the streets.

"We do expect to, over time, create a network of tunnels under greater LA," he said, "and I think this is really the key to getting around the city very fast. You've got to go 3-D."

"You could certainly have a subway system which had many layers of tunnels, but the tunnels are so prohibitively expensive that they don't do it. But you can go down 100 levels if you want to, you could have 100 layers of tunnels on top of each other … the key is a massive improvement in tunneling technology. That's the linchpin, that's fundamentally what it amounts to."