Elon Musk unveiled his underground transportation tunnel on Tuesday, allowing reporters and invited guests to take some of the first rides in the revolutionary albeit bumpy subterranean tube - the tech entrepreneur's answer to what he calls "soul-destroying traffic".
Guests boarded Mr Musk's Tesla Model S and rode along Los Angeles-area surface streets about a mile away to what's known as O'Leary Station. The station, smack dab in the middle of a residential neighborhood - "basically in someone's backyard", Mr Musk says - consists of a wall-less elevator that slowly took the car down a wide shaft, roughly 30 feet (9 metres) below the surface.
The sky slowly fell away and the surprisingly narrow tunnel emerged.
"We're clear," said the driver, who sped up and zipped into the tunnel when a red track light turned green, making the tube look like something from space or a dance club.
The car jostled significantly during the ride, which was bumpy enough to give one reporter motion sickness while another yelled, "Woo!"
Mr Musk described his first ride as "epic".
"For me it was a eureka moment," he told a room full of reporters.
He said the rides are bumpy now because "we kind of ran out of time" and there were some problems with the speed of his paving machine.
"It'll be smooth as glass," he said of future systems. "This is just a prototype. That's why it's a little rough around the edges."
Later in the day, Mr Musk emerged from the tunnel himself inside one of his cars. He high-fived guests and pumped his fists in the air before delivering a speech in the green glow of the tunnel about the technology and why it makes sense.
"Traffic is soul-destroying. It's like acid on the soul," he said to guests who snacked on marshmallow treats and hot dogs and hoped for a turn in the tunnel.
On Tuesday, he explained for the first time in detail how the system, which he simply calls "loop", could work on a larger scale beneath cities across the globe. Autonomous, electric vehicles could be lowered into the system on wall-less elevators, which could be placed almost anywhere cars can go. The cars would have to be fitted with specially designed side wheels that pop out perpendicular to the car's regular tires and run along the tunnel's track. The cost for such wheels would be about $200 or $300 a car, Mr Musk said.
A number of autonomous cars would remain inside the tunnel system just for pedestrians and bicyclists. Once on the main arteries of the system, every car could run at top speed except when entering and exiting.
"It's much more like an underground highway than it is a subway," Mr Musk said.
The cars would have to be autonomous to work in the system but not Teslas specifically, and they would have to be electric because of the fumes from gas, Mr Musk said.
The demo rides were considerably slower - 64 kph - than what Mr Musk says the future system will run at: 241 kph. Still, it took only three minutes to go just over a mile from the beginning to the end of the tunnel, the same amount of time it took to accomplish a right-hand turn out of the parking lot and onto a surface street even before the height of Los Angeles' notorious rush-hour traffic.
Tuesday's reveal comes almost two years to the day since Mr Musk announced on Twitter that "traffic is driving me nuts" and he was "going to build a tunnel boring machine and just start digging".