1. 1 University of Žilina , Department of Railway Transport, Faculty of Operation and Economics of Transport and Communications , Univerzitná 1, 010 26 Žilina , Slovakia
2. 2 University of Žilina , Department of Road and Urban Transport, Faculty of Operation and Economics of Transport and Communications , Univerzitná 1, 010 26 Žilina , Slovakia
3. 3 University of Žilina , Department of Quantitative Methods and Economic Informatics, Faculty of Operation and Economics of Transport and Communications , Univerzitná 1, 010 26 Žilina , Slovakia
4. 4 Evangelista Purkyně University in Ústí nad Labem , Faculty of Social and Economic Studies , Pasteurova 3544/1, 400 96 Ústí nad Labem , Czech Republic