The Tesla CEO unveiled how much passengers will have to pay to ride the futuristic transportation system that he hopes to build beneath the city—and at just $1, it costs less than bus fare. One of the tunnels, he said, would connect downtown Los Angeles to the Los Angeles International Airport in just 10 minutes.

“This system is designed to be more like a highway and a bunch of off-ramps and loops connecting to the highway, kind of like cars,” Musk said on Thursday night on stage at a synagogue in Los Angeles. “Almost like an autonomous underground, multi-level car system…that costs a dollar.”

Musk’s tunnel-building firm, the Boring Company, would handle project, which he hopes will alleviate traffic in the notoriously gridlocked city. Earlier this month, he shared an image of a test tunnel his firm dug. Details on that tunnel are sparse: “The exact location of the tunnel shown in the video was not clear,” the Los Angeles Times reported. “It is believed the digging so far has occurred in and around his property in the Hawthorne area.” Last year, he shared an image of a tunnel that was reportedly 500 feet long.

The planned tunnels would be used for what he calls “Loop,” or a “high-speed underground public transportation system in which passengers are transported on autonomous electric skates traveling at 125-150 miles per hour.” The electric skates would carry six to eight passengers or one vehicle.

“Compared to a flying car,” Musk said on Thursday, “you don’t have to worry about bad weather, you can’t see it, hear it feel it, you’re not dividing communities with lanes and we think we can make this really fun.”

Of course, there are road blocks to this loop system: neighborhood groups are mounting legal challenges to a 2.7 mile test tunnel that would run along Sepulveda Blvd. from Pico Blvd to Washington Blvd. Last month the city council’s public works committee approved an environmental review exemption for the project.