A previous study of river magnitude and frequency established river exiting as the primary problem for vehicles attempting to cross rivers. Analysis of the exiting problem indicated that the single most important parameter to be considered was the geometric form of the river bank. Evaluation of the probability of an M-113 exiting at each bank surveyed in the magnitude and frequency study was made by relating vehicle performance characteristics to bank descriptions a determination of the probability of the vehicle exiting was then made on a GO or NO-GO basis. Since much of the environment was extremely severe with respect to M-113 capabilities, this evaluation was fairly straightforward. A numerical method, using a geometric severity to classify bank geometry, was then developed to permit a performance analysis to be conducted on a rational basis.