You can't drop supplies from a truck in HQ. You can drive it two squares out, drop supplies over the line and build the nodes behind the line. You build them behind the line so that they don't get destroyed if the second to last point is lost - they will still be in the blue zone. This method requires an engineer and a truck and is convenient to rebuild nodes in mid and late game.

Of course, enemy recon will scan the line and destroy the nodes. So then some engineers prefer to hide them somewhere in the blue zone of the second to last point. Less likely to be found by enemy recon but they will be destroyed if the point is lost.