The existing methods of reducing open transport problems to a balanced form, namely: the method of fictitious supplier / consumer, the difference method and the method of coefficients. The transport problem is a special case of the general problem of linear programming, so it is also possible to apply the most well-known method of solving problems of this class - the simplex method, pre-grafting the transport problem to the form of linear programming problem and taking into account its specificity. Experimental studies on the optimization of unbalanced freight traffic, which were obtained using the developed decision support system, allow us to conclude that the simplex method has shown high efficiency in finding optimal freight plans for both balanced and unbalanced transport problems. Analysis of the results of the use of all methods on many practical examples allows us to conclude that none of them has an absolute advantage over others. This fact is explained by the fact that each of the methods in some cases of its application showed a better result compared to the results of others.