Get outta the way(other side of the road is ok if you ask me) since they ain't slowing down for no cyclist.... those guys can barely stop at intersections. dangerous.
a) rocks and dirt will go flying in your face if you are close.
b) pressure wave from truck can suck you over.
c) truck will have to switch out of the tire tracks if you are in one of the tracks and this makes controlling it harder and flings more crap around. Many drivers won't want todo this and that will be very dangerous for you since that makes for a very close pass if you are on the shoulder and they choose not to switch tire tracks.
d) be super visible, if it is raining the trucks will have even less control.
e) if two trucks are coming at once from opposite directions seek cover - just get off the road.