Revealing the Phenomenon of Rank Reversal in Decision-Making by Studying Railway and Road Routes in the Transport Network Using the SIMUS Method

The sustainability of transport planning in intermodal route selection depends on the examination of a set of criteria and alternatives. This paper investigates a dynamic decision-making process by studying the change in ranking when a new alternative is added, or an existing alternative is removed; or when a new criterion is added, or an existing one is removed. The presence of a change in ranking reveals the phenomenon of rank reversal (RR) in multi-criteria analysis. The Sequential Iterative Method for Urban Systems multi-criteria method (SIMUS) is presented as a tool to study the rank reversal problem. The methodology of the research consists of six steps. In the first step, the initial decision-making matrix is compiled. The second step includes the compilation of new decision-making matrices by adding or removing alternatives from the initial decision-making matrix. In the third step, the SIMUS method is applied. In the fourth step, the influence on rank reversal of the addition of alternatives that are very similar or identical to another existing in the system is analyzed. In the fifth step, the influence of a change in the number of criteria on the rank reversal is studied. The sixth step includes determination of the entropy and information of the system. A case for the sustainability of container carriage by railway and road routes between Sofia and Varna in the Bulgarian transport network is demonstrated. Three railway routes and three road routes served by different types of locomotives and heavy trucks have been studied. The routes were evaluated according to the following criteria: CO2 emissions, operating costs, infrastructure fees, travel time, route length, safety and security factor of transport. The change in the ranking of alternatives was studied by comparison of rankings for cases from 3 to 12 alternatives. A hypothesis based on the assumption that RR in the SIMUS method is a logical consequence of linear transformations along different dimensional spaces, each time an alternative is added or deleted, has been introduced. An invariance coefficient and a rank reversal coefficient have been defined. The values of both coefficients have been classified into groups to explain sustainability in decision-making.