rogue49: not true.. some have both
although in the 500 miles i generally travel, I only see two of these, and it is only when I am coming near a large city.
don't worry about finding lodging and a place to eat.. if they are near the interstate, they usually will let you know right before the exit.. just make sure, if you plan on stopping soon, if you are out in the middle of no where, take the first one you come to.. it might be a while till the next exit.
it is better to get gas a bit before you have to rather than run out a few miles too short