Elon Musk has a great idea for curing traffic congestion in big cities

Elon Musk has a simple, fairly obvious solution for curing traffic congestion in cities: "More tunnels."

The way Musk sees it, we have dense cities with big buildings that extend into the sky taking full advantage of our three dimensional world. But, when it comes to transportation, we are stuck in two dimensions. We only drive at the surface level. He thinks we should dig underground to transport ourselves. We should be taking advantage of a third dimension, so to speak.

Musk talked about this during an interview with Neil DeGrasse Tyson on his radio show, StarTalk. DeGrasse Tyson asked Musk about flying cars.

Musk thinks flying cars are problematic. He said they increase the chance of something falling on your head. He said they would be loud. He said they would have to deal with bad weather. And, "of course," they would have to be auto-piloted.

"Essentially with a flying car you're talking about 3D," said Musk. "There's a fundamental flaw with cities where you've got dense office buildings and duplexes and they're operating on three dimensions, but then you go to the street and you're two dimensional."

DeGrasse pointed out that New York City has the Subway which is based on underground tunnels that are built atop each other adding another dimension for transportation.

"If you were to extrapolate that to cars, and have more car tunnels, then you would alleviate congestion completely. You would not need a flying car in that case," says Musk. "And it would always work, even if the weather is bad. It would never ice up and it would never fall on your head."

While it seems far fetched to think about a massive project like digging tunnels in big cities, it seems much more feasible than flying cars.