IAB has been following this story for a while now -- Elon Musk's whimsical underground freeway system, build by his "boring machine." Sorry dude, you've done some pretty innovative things, but you'll never pull this underground freeway stunt.
I mean, I'd love to see this happen, but that means -- if you go by this video made by his Boring Company -- hollowing out half the earth underneath Los Angeles. This idea will be great once he colonizes Mars, but in an already-established city with millions of people? Nope -- not in this millennium.