You can make money at $1.50 a foot. Just depends on volume. Yeah I wouldn't do span replacement or maintenance at that price but if you've got 50 miles out in a ditch $1.50 is just fine.
Also depends on the area. $1.50 in texas or somewhere in the midwest will make money. $1.50 in Cali or the Mountian states won't make money.
Trying to talk about rate without knowing the full scope of the project is like trying to build a house with no blueprints.