I think my new strategy for the post office is to go past the usable entrance, park on the street, and take a longer walk to and from the building. The one legal car exit has signs directing everything one way toward more road construction and ignoring the big do not enter on the other entrance like most people seem to do is unreliable as traffic can get backed up there with surprising rapidity. Not using the post office's parking lot preserves the best options for leaving.