Having spent a lot of time in a truck, I can tell you it's extremely difficult to cope on high-traffic roads. Most car drivers will crowd around you giving you no chance to change lanes, etc. Sometimes you have no choice but you just start creeping over and scare everyone out from around you. Obviously most truckers know what they're doing and they won't actually run you over -- it's bad for them, too.
When I'm out on the highway in a car and I see a truck ahead of me trying to get over into my lane, I'll most likely slow down to hold up the lane behind me and give them a quick headlights flash to they can get over. I'm sure the other cars hate me for it, but who cares.