As someone who grew up in the Appalachians and now lives in central Indiana, I think it's important for this discussion to remember that different people have different definitions of the word "hill".
I suggest that one should probably drive steep hills differently than lesser grades (such as a overpass).
Where I drive here in IN, all we have a those lesser grade, and most of the time it's level-up-down-level again. Here's my philosophy as far as those go: I try to maximize the amount of "pulse" I have on the upward grade and maximize the amount of "glide" I have on the downward grade. Generally that means timing things so I end my pulse at the top of the "hill". Depending on the length of the "hill" that may mean starting a pulse at the bottom or maybe not.
Of course, all this depends on traffic too.