Elon Musk, Tesla Factory, Fremont (CA, USA) in 2011. Credit: CC BY 2.0

Billionaire Elon Musk says he's almost completed a tunnel under a Los Angeles suburb to test a novel transportation system that would scoot commuters underground on electric sleds called skates.

Musk tweeted Thursday that, pending regulatory approvals, free rides will be offered to the public in a few months. He also posted an Instagram video of the interior of the tunnel.

Last year, the Hawthorne City Council approved an approximately 2-mile (3.2-kilometer) test tunnel from Musk's SpaceX rocket plant to a point east of Los Angeles International Airport.

Musk has described a system in which vehicles would descend via elevators into tunnels and move on electrically powered platforms called skates. He envisions multiple levels of tunnels to escape congestion that plagues surface traffic systems.

"As mentioned in prior posts, once fully operational (demo system rides will be free), the system will always give priority to pods for pedestrians & cyclists for less than the cost of a bus ticket," Musk tweeted.

Musk's tunneling operation, called The Boring Co., is currently seeking approval to push into the city of Los Angeles, which requires separate authorization. So far, a committee of the City Council has agreed that the project should be exempt from environmental review.

Musk suddenly added tunneling ideas to his SpaceX rocketry and Tesla electric car endeavors more than a year ago.

A few weeks after tweeting "Traffic is driving me nuts" and "am going to build a tunnel boring machine and just start digging," he said in January 2017 that tunnel was about to get underway. He acquired a tunnel-boring machine that had been used in a San Francisco Bay Area project and put it down a shaft in a parking lot at the SpaceX facility in Hawthorne.

He has also tweeted about a vision for a tunnel that would stretch along the Interstate 405 corridor from LAX to U.S. Highway 101 in the San Fernando Valley, a span of about 17 miles (27 kilometers). It's among the most notorious examples of what Musk has called "soul-destroying" Los Angeles traffic.

Musk has also advocated another transportation concept called the "hyperloop," a network of nearly airless tubes that would speed special capsules over long distances at up to 750 mph (1,200) kph), using a thin cushion of air, magnetism and solar power.

On Friday, SpaceX successfully launched Bangladesh's first satellite into orbit from Cape Canaveral, Florida, using an upgraded Falcon 9 rocket designed for dozens of repeat flights including back-to-back, same-day launches. The rocket's first stage was successfully recovered, landing upright on a platform floating in the Atlantic Ocean.

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