Indistinguishable binary strong molecular collisions at the instant of the closest approach (t = 0) when contribution of such collisions to the cross section is maximum are illustrated by the example of CO self–broadening. An analysis of indistinguishable collisions shows that only our refined Anderson––Tsao––Curnutte––Frost (RATCF) model adequately describes these collisions and hence the representation of the principle of conservation of momentum for the RATCF model is correct.