Aero modelling in LFS is very simple and I don't really think it evens attempt to recreate the aero trail, save for slipstreaming and downforce (partially, e.g. there's no ground effect).
That effect is caused by pressure differences in the aero trail of the truck, and the intensity of forces you feel depends by the side surface of the car. Since in LFS there are no trucks and all the cars have quite low profiles, I doubt the effect would be so strong as in the situation you were using as an example.