broadsword says:
Expressed in Paint, this is what you're supposed to do:
So, the same route, driveable in both directions. Not two routes which happens to have the same start and finish.
Since not everything is driveable backwards, some freedom is granted within reasonable amounts.
Yea, in model like that racers meet 1 time, in my case racers meet 3 times and it was really hard to push through
edit: if racers start at same time and choose different directions they will meet still at second and third checkpoint almost equally.