By comparing approximate and exact transition probabilities for several new collision systems, we have established lower, less restrictive, values for validity criteria for use in predicting which collinear atom-triatom or diatom-diatom collision systems could be reliably treated in the vibrational sudden approximation. The specific lower bounds for the atom-triatom (A + 1-2-1) validity criterion, 2m(1)(2m(1) + m(2) +m(A))/[m(A)(2m(1) + m(2))], and the diatom-diatom (A(2) + B-2) validity criterion, m(B)/3m(A), are 14 and 6, respectively.