I am reading this and I don't know what to think of it.

"officials say a tunnel under the New River would cost more than $3 billion. Instead they have proposed a 55-foot high-bridge that would cost an estimated $445 million.But Musk’s team estimates it will cost anywhere $30 million to $60 million to build a 3-mile tunnel"

How can The Boring Company build a tunnel at 1/100th or 1/50th of what would cost by other builders?

What is going on here?

Please read it for yourself:

https://www.msn.com/en-us/news/us/vegas-may-hold-answers-about-elon-musk-tunnel-under-new-river/ar-BB1d9n5V