The article presents an analysis of the possibilities of using RIS to assess the probability of collision during
the transition of inland vessels under the bridges on the Odra River. Operational and technical analysis of the
bridge structures and their restrictions affecting shipping in the area are also presented. The analysis of the
traffic streams of the vessels under the bridge in Radziszewo and the bridge in Gryfino was made on the basis
of the AIS data. The number of vessels in the selected area was divided into type and length. The probability of
an accident, like collision during an overtaking and passing manoeuver, was defined.