d9, now we're down to left hand drive trucks being dangerous. Well, lhd or rhd, they don't exactly shoot out to overtake do they? You have plenty of time to press on , or hang back, and avoid even the speediest, bliond spotted,enthusiastic, must stubborn, truck driver.
We seem to have wandered away from the OP, which was about slow driving, to overtaking. All vehicles, but trucks least of all, because of their comparative slowness, are potentially dangerous when they pull out to overtake. And the most dangerous are those which pull out quickly, in ignorance of, or oblivious to, the traffic which is close outside them.