This is the first I've seen Gareth's assumtion confirmed as the desired intent, i.e., that the starting and ending locations are in fact in the centers of street intersections, rather than one of the street corners as in any real-world situation. Given this unintuitive definition, I would suggest that the term "jaywalking" is misleading, since even under the most extreme defintion of jaywalking, these paths do not qualify. Perhaps some term that does not involve walking would make more sense. Tom Keith F. Lynch writes:
Since we're starting and ending in the middle of the width, it makes more sense to use Gareth's half-width h than my full-width w. You can use the same equations with w replaced by h, since you just have narrower rectangles.