To quantify the risks involved in Ro-ro passenger vessel traffic, rational criteria for prediction and evaluation of collision accidents have to be developed. This implies that probabilities as well as the inherent consequences have to be analyzed and assessed.The present report outlines a method for evaluation of the probability of a Ro-Ro passenger vessel on a given route being struck by another ship. Given a collision has taken place the spatial distribution of the collision damages is calculated. Results are presented in terms of probability distributions, for indentation depth, length and height of the holes and for the vertical location. The main benefit of the formulated procedure is that it allows comparisons of various navigation routes by assessing the relative frequencies of collisions. The derived procedure is applied to two typical Ro-Ro passenger vessel routes.