>The amount of congestion is approximately equal to the amount of congestion the average person using the infrastructure is willing to accept, so making it less congested just means more people use the infrastructure until the limit is reached again.
This is true only for places where there is more latent demand for transit than physical space to build it (e.g., a lot of big cities without good transit alternatives).
It is not a law of physics. You could go to a small town in North Dakota and build more roadway than can ever be used and, in doing so, permanently remove gridlock.
Efficient tunneling would let you do this in three dimensions, so it would expand the types of places you could do this.
This is true only for places where there is more latent demand for transit than physical space to build it (e.g., a lot of big cities without good transit alternatives).
It is not a law of physics. You could go to a small town in North Dakota and build more roadway than can ever be used and, in doing so, permanently remove gridlock.
Efficient tunneling would let you do this in three dimensions, so it would expand the types of places you could do this.