Birden fazla amaç ve kullanıcı sınıfı ile sürdürülebilir rastlantısal trafik ataması

As the global warming has become a major concern, the sustainability of transportation is an actual and crucial issue. Within this context, defining criteria in relation with the transportation sustainability and by using these criteria, measuring the performance of the transportation systems and increasing their efficiency is an active research area. In this study, we introduce some social, environmental and economic criteria to evaluate the sustainability of a solution developed for the traffic assignment stage of the urban transportation planning: accessibility to the network centers, equity in the accessibility to the centers, number of road accidents, carbon dioxide and noise emissions due to the transportation vehicles, and affordability of transportation for the individuals. Then, we develop a bilevel mathematical model to assign the traffic flow in a sustainable way by paying attention to these criteria. The lower level of our bilevel model includes the stochastic user equilibrium, and concepts such as multinomial logit choice and multiple user classes are considered at this equilibrium model. Our main aim is to identify each user class optimum toll pricing scheme at the upper level of the bilevel model while taking into account social, environmental and economic objectives. As multiple objectives exist at the upper level and these objectives are in conflict, we try to generate the Pareto optimum solution set. To achieve this, we use the Non-Dominated Sorting Genetic Algorithm which has a proven performance record for solving multiobjective optimization problems. At each iteration of the genetic algorithm, the stochastic user equilibrium problem is to be solved for each individual (toll pricing vector) of the current population. Consequently, we use the Self-Regulated Averages Method which enables to solve large size problems efficiently by concentrating on the network links instead of the network paths. Finally, we solve some well-known transportation network planning problems from the literature by using the developed solution method and elaborate on the obtained results.Keywords : Sustainable traffic assignment, Bilevel programming, Multiobjective optimization, Stochastic user equilibrium, Non-dominated sorting genetic algorithm