Elon Musk tweeted that his Boring Company will unveil a stretch of a rapid-transit tunnel under Los Angeles to the public on Dec. 10.
What the company has previously termed a "test tunnel" in the southern suburb of Hawthorne, between downtown LA and Torrance, demonstrates the company's "Loop" system. People are whisked through the system's tunnels at up to 150 miles per hour.
They travel on an electric-powered platform called a "skate." The device either comprises a vehicle itself carrying between eight and 16 passengers or carries a car that has been driven onto it.
Elevators move skates between the surface and the tunnel system. When completed the system would employ a series of tunnels, layered and moving in various directions, with shorter segments serving as subterranean off-ramps. Shafts for the elevators could run straight up to streetside locations, as in a company video, or into homes' garages or basements of office buildings.
More from USA Today:
Information about the "Loop" tunnel segment's opening came in short tweets Sunday night from Musk.
"The first tunnel is almost done," he tweeted Sunday night. "Opens Dec 10," he typed to his 23.1 million followers soon afterward.
"Opening event that night & free rides for the public the next day," he replied to a Twitter user's question later.
Boring Company's Hawthorne tunnel runs a short stretch from SpaceX property north to 120th Street, then west under 120th "for up to" two miles, the company says. SpaceX is another of the groundbreaking, tech-oriented companies run by Musk, also the CEO of Tesla.
The Loop system is distinguished from proposed, longer-range Hyperloop projects. in the latter system air is sucked from the tunnels, which (as the Boring Company envisions) enables pods to exceed 600 miles an hour.
Hyperloop tech is also touted by Virgin Hyperloop One, whose board is chaired by Richard Branson, and Hyperloop Transportation Technologies (Hyperloop TT). Hyperloop One mentions using tubes whether above ground or below and is pursuing a Kansas City-to-St. Louis route using magnetic levitation to support vehicles in tube. Hyperloop TT recently unveiled a prototype, 40-passenger capacity pod in Spain.
WATCH: Elon Musk's new underground tunnel project will transport cars at 125 mph