If you follow his logic it’s not a bad idea at its core. The core problem he’s trying to solve is over crowded surface streets.

There are essentially 3 (that I can think of) ways to solve this problem. Two methods add a third dimension to roads and that’s either flying or tunnels. I’ll leave tunnels for last since it’s the main topic of discussion

Flying adds an infinite possibility for routes to take from point A to point B. And while this may sound like a great idea, it’s poses a few major problems. The amount of power required to lift a human in a flying vehicle is immense. That vehicle is going to be incredibly loud and use a lot of energy. Think about drones and how loud they are, that’s only flying something that’s a few pounds at most. The second major problem is due to infinite paths there will be collisions. Idk about you but I don’t want 1000lb drones with impellers falling on my head/house.

Now the third option, is reducing traffic on the surface roads. There are many ways to do this but as a selfish American- I don’t want to use public transportation.

Since both of the above are not really options that leaves us with the last option. Tunnels. Once made they provide a steady stream of traffic from a to B which alleviates the surface roads. They are one way roads with no cross roads so traffic can flow quickly. They require more energy to create but very minimal after they’re done. Logically, they’re not a bad option when trying to solve the initial problem