Highway 7 - Kitchener to Guelph

[SammyOES]

I'm curious about the tree clearing thats been happening along the whole route. I had imagined that they'd be clearing a strip of land from start to finish along the whole route, but now it sort of looks to me that its more like they're clearing individual areas that are then going to be staging areas or starting areas for work.

Does anybody know how these things usually work? Do they start with things like the overpasses and fill in highway later? Do they start at various points and work outwards, start at one end and go to the other, something else entirely?