MAYA _ Motion path no flip

Sometimes while using motion path, flipping is hard to avoid, here is one solution :
- motion path your main object to the path "path1" blue curve
- duplicate "path1, rename it to "path2", offset it, delete history and edit it to shows the direction pink curve
- create a locator "loc1" and motion path it to the path "path2"
- connect the Uvalue of "path1" to "path2" so they have the same speed
- in the motionpath1 attribute, set follow, object up and in the world up object field enter "loc1"

EDIT : Actually the best method is by far to use a curve on surface as motion path and choose the normal type. To create a curve on surface, first create a surface, then make it live and create a curve on it.