Our county's Mosquito Control division has asked us to update thier fog zones so that they accurately represent areas that can be driven for three hours, going fifteen miles per hour. All of their vehicles are dispatched from a single location, but they don't need to restrict their travel time until they reach their assigned zone where they start and stop spraying.
Is it possible to create non-overlapping service areas without using facility locations? Kind of like a tessellation, but instead of equal areas of land, it would be area in a road network by travel time.