Elon Musk was recently interviewed by Gayle King of CBS This Morning, where he revealed his new invention that might be the long-awaited solution to gridlock traffic. Musk has been working on a new set of underground tunnels, with a test site already built in the city of Hawthorne near Los Angeles.

Through his own tunnel construction company coined, The Boring Company, Musk and his engineers started building the 1.2-mile tunnel last year, and now his electric cars are already traveling through them at accelerated speeds. Musk’s vision involves an entire underground network, where electric cars will use street-level elevators that take them down into a series of underground tunnels where they can travel at speeds up to 120 mph.

To ensure safety, Musk explains that the cars “autopilot has radars and cameras that will automatically slow you down before you impact another car,” before adding that you’ll only be allowed to go through the tunnel on the autopilot setting.

Musk further explained that his motivation simply came from being tired of LA congestion, while realizing that “either we try something new or we’ll be stuck in traffic hell for the rest of our lives.” He elaborated by saying the underground network is “the only solution to urban congestion because we have a 2-D road network with buildings in 3-D.”

Furthermore, Musk says he can produce these tunnels faster and cheaper than industry standards, considering that while modern subway tunnels in LA cost upwards of $900 million per mile, Musk’s 1-mile tunnel cost him only $10 million by creating all the materials himself. It should be noted that Musk was set to build a second tunnel in Brentwood, Los Angeles, yet the community shut him down. Nonetheless, Musk believes his idea will one day revolutionize cities across the globe.