Big vehicles need more room, take longer to stop, and can't see you where a car could. Give them space and stay out of their blind spots.
Following and blind spots
Following a truck or bus, keep the two-second rule — four seconds in the wet. Following too closely hurts your view of the road ahead, gives you less time to stop, and puts you in their blind spots. Stay far enough back to be seen in their side mirrors: if you can see their mirrors, they can see you.
Overtaking and oncoming
Overtaking a truck or bus takes several seconds longer than passing a car, so make sure you have plenty of clear road to complete the pass without exceeding the speed limit. When a large vehicle is coming the other way — especially around bends or at intersections — expect it to take up more room and perhaps not stay fully in its lane, and keep firm control of your steering against the turbulence as it passes.