Musk—who had previously envisioned “electric pods” and vehicles on “electric skates” traveling through the tunnels—now believes the best use of the infrastructure is to move autonomous electric cars outfitted with “tracking wheels,” which would guide the cars along the tunnel, deploying when inside the tunnels and retracting when on the street.

Though reporters in Hawthorne were given a taste of the technology in Tesla Model X SUVs—which traveled at only 40 to 50 mph—he insists the tunnels aren’t only for his customers. “This is not intended to be some walled garden just for Teslas,” he said. “Any autonomous electric vehicle can be outfitted with these guide wheels.”

Elon Musk, co-founder and chief executive officer of Tesla Inc., arrives in a modified Tesla Model X electric vehicle during an unveiling event for the Boring Company Hawthorne test tunnel in Hawthorne, Calif., on Tuesday, Dec. 18, 2018. The tunnel, meant to be a "proof of concept," runs just over a mile under Musk's SpaceX headquarters in Hawthorne. (Robyn Beck/Pool Photo via AP)
Test run.
Image: Robyn Beck/AP

Nor are the tunnels only for car owners, actually. Musk hopes to have cars continuously operating in the loop for pedestrians, he added.

The demonstration tunnel cost about $10 million to build. Cars would enter and exit the tunnels—a system he says is infinitely expandable by simply building more of them alongside one another—via elevators, which would act as stations of sort. To install these elevators, he said the company would drill a hole roughly the size of two parking spaces and install prefabricated lifts in sections. He did not mention the possibility of gridlock as cars queue to exit the tunnels.

“You can think of these as wormholes,” he said. “You drop down the wormhole, pop out the other side, and then you drive normally.”

As he closed out his presentation, he also teased the possibility of these tunnels connecting to the high-speed rail project Hyperloop, another unrealized concept he’s dreamed up that would transport people between Los Angeles and San Francisco in under an hour.

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