Adaptive flow time step

The idea is to adapt the flow time step depending on the vehicle and its situation so as to save computation time in moving the vehicles. For all personal vehicles, the flow time step can be increased when the vehicle is moving within a reservoir and is not about to finish its activity. The adaptive time step should be deployed for the vehicles belonging to mobility services that do not require precise vehicle location, depends on the percentage of distance traveled compared to the total distance to travel, and on the distance from current reservoir's border.