Elon Musk’s Boring Company is getting closer to becoming a reality.

The businessman conceived the idea in December in response to the pain of clogged up roads and traffic jams, and it has begun to take shape thanks to work carried out this summer.

The basic idea is that underground tunnels can transport vehicles from A to B more quickly and efficiently than roads, with no time wasted sitting in traffic. A car drives into a collection point located on the surface, after which it is taken underground via an elevator and moved to its desired destination using a sled on wheels that traverses a network of underground tunnels. Essentially, it’s an underground railway system for vehicles, and potentially more.

Musk shared details of the elevator last month, saying at the time that it was close to operational, and now he’s published footage of one in action. The tunnel networks themselves will take more time to complete, of course, but it’s a sign that this ambitious project is moving forward with speed.

Testing The Boring Company car elevator A post shared by Elon Musk (@elonmusk) on Jul 25, 2017 at 11:26pm PDT

The theory is shaping up to become a reality, and Musk hasn’t wasted time getting buy-in from key authorities. He said before that he had gotten “verbal approval” from the government to build a network to connect New York, Philadelphia, Baltimore and Washington DC, and he has held “promising” talks with L.A. Mayor Eric Garcetti over the project.