Anecdotally the petrol station thing aligns with my experience, and my preference for filling up on the way home.
Slightly different situation for Mcdonalds though - they're trying to market convenient, fast breakfast food to morning commuters. If the location is most convenient to city-bound traffic, I think it would have a bigger positive impact on morning revenue than the corresponding negative impact on evening revenue. People are in a hurry in the morning!
