Bugging me

Why do trucks get the right to have the sign that warns us that we need to be alert for "sudden stops and turns." If I do that, I get a ticket. I think it's really ridiculous that truckers get the right to make sudden stops and turns. What's the problem? Why would they need to do that? I will give you the stop part. Sometimes we ALL do that. How about the turn part? Don't they know where they're going?