Except planned buildings from pathfinding

Currently, if you place buildings in plan mode, transporters and excavators will adjust their pathfinding as if the buildings were already there. I would suggest they should be "invisible" to the truck drivers, as they are only planned and not built yet.
The current state blocks planning a factory when you don't have the material to actually build all bridges ahead so the trucks can drive over the virtual belts and stuff.
I'm surprised I didn't find anything about this on current topics when searching for "plan mode". Actually it's my first ever suggestion to any game out there so I'm not quite sure if this fits.

I would adjust that suggestion to only buildings in planning mode, meaning they are not confirmed for construction - consider how when IRL construction is approved, an area around the construction is surrounded with either fences, tape markings with spikes or any other way of making sure no one goes through that area.
Granted, this is not as the OP proposal inteads, as I think the OP wants vehicles to be able to traverse the building site where a building is not built yet, but I think whatever is already established and confirmed should be unavailable for vehicles to pass through as opposed to what is only a plan "on paper",
The end result should be that vehicles will not get stuck just because I planned a pipe in it;s exit path...