Welcome to this short but confusing Hell Park.
In this Hell Park, you discover a Plane Composition.
This is easy: you need to go up (because, you see, there is a checkpoint on top and, you see, you need to go through all the checkpoints of a map to finish it), and then you need to go over the fence to go back down (because, you see, the finish is in the ground and, you see, you need to reach the finish to complete a run).
Also, please don't jump over fences in real life, especially of you're driving a car.
In real life, you take the risk to seriously damage your car and yourself, and there are probably no track finish after the fence anyway.
Also, there a GPS in the finish but, unfortunately, it doesn't trigger if you have already taken all checkpoints of the map before reaching it
.