Passing a restricted area the ship’s master has to select one of the alternative routes or decide on a delayed passage. Among important imprecise and subjective val-ues are congestions encountered within the regions including route crossings or junc-tions. To foresee traffic within a confined area the decision maker has to cope with im-precision and to use fuzzy numbers. Fuzziness is expressed by intervals. Interval arith-metic embraces typical operations such as addition or multiplication, but also enables the selection of possibility level as well as the comparison of such values. Consequently, extended popular hierarchy builders can be used for the selection of the best option.