My feeling is, when you don't have anything interesting going on in the sky...then it shouldn't be any more than 1/3 of the image. Your composition would have been helped by loosing much of the wasted space on top.
Did you take this driving? Done that many times when wife couldn't/wouldn't stop... :) The blur in foreground is a little distracting. If you couldn't stop, maybe crop a bit to get the blurrier parts out?