Some circumstances in which vehicles will reach their destinations earlier by starting later.

Since the speed of travel on a road usually decreases as flow increases, there are often advantages in extending the period over which travellers on a road system begin their journeys, but, since travellers often wish to reach their destinations almost simultaneously, there journeys. This suggests that there may be an optimum period during which vehicles should begin their journeys on a road system in order to reach their destinations within the shortest possible time.