Let alone cost, one thing that boggles my mind is how slow infrastructure building is in the US. In our area, a multi-billion dollar freeway or subway line will often be constructed with 5 days of a single 8-hour shift. I get that certain work needs to be done at night, but surely the work sites shouldn't sit empty for 16 hours a day!

Just think about the cost of equipment being rented, the overhead that is on salary, the amount of work to startup and shutdown the site for the day, and the opportunity cost lost by not having it done 2-3x as fast.

It's seems like it would be a no-brainer to have 3x the workers and get the job done in 1/3 the time.