possible fix is to drive the whole semi with trailer by the same skeletton. and then rigid bind the semi to the root - put the next start of bone where the trailer connects - limit the rotations - add a ik chain to end wheels of trailer.

now for realistic animation you need to have a differant curves for the semi and the trailer in curves. it is just not possible that the trailer follows exactly - it kind of takes shortcuts.

or i misunderstood your problem with the wheels skidding.