This function is mostly used by the transit types: Subway, Train, Funicular - it helps you save time by inverting the path.
This is a quick solution for cases when the vehicle uses the same stops or stations when traveling in both directions.
Important note:
This is NOT a solution for bus trips because a bus travels in opposite directions using different stops on opposing sides of the road. Please do not use this option for bus lines since the data will be inaccurate.