Passenger satisfaction evaluation for rail transit lines in Istanbul using qualiflex approach based on interval type-2 trapezoidal fuzzy numbers

Traffic congestion is one of the vital problems for the residents who live in big and crowded cities or metropolitans like Istanbul. Any increment in passenger satisfaction level can attract further passengers to use public transportation systems. Consequently, higher public transportation usage could help reducing many problems in transportation like traffic congestion in Istanbul. Evaluating and improving the passenger satisfaction level in public transportation systems are crucial operations for the majority of public transportation engineers, operators and authorities. For this purpose, Istanbul Public Transportation Co., the only rail transit service provider of the Istanbul, conducted a survey to question the satisfaction of the passengers with respect to rail transit lines considering multi criteria in 2013. In this paper, a QUALIFLEX approach, using a ranking method based on interval type-2 trapezoidal fuzzy numbers, is proposed to evaluate the passenger satisfaction level for rail transit lines in Istanbul through the survey. In this survey, twenty six different passenger satisfaction criteria are taken into consideration for evaluating passenger satisfaction.