I was watching an interview with Elon Musk explaining the purpose of “The boring company” last year. To paraphrase him slightly he says that currently traffic congestion is a 2-dimensional problem. The only 2D solution is to make wider-highways to accommodate the growth in traffic.
However, there is another way. By going into another dimension, the 3rd-dimension, you can go either over or under the traffic. Doubling the space for the same amount of traffic, thus reducing congestion.
