@KayTwo very good explanation of things. I will just add that if the hump is big enough and there were no plans to replace that section of road, we grind the jumps down with a road grinder attached to a skidster. You are right that "do nothing" is usually the course of action.
well, it dawned on me that the do-nothing course of action isn't always exactly, strictly, do nothing. Where I grew up, they would just put up a sign, one of the diagonal yellow caution type signs, that would just say "Frost heave," and leave it at that.