Sharif Digital Repository

In recent decades, widespread application of Linear Complementarity Problems in various branches of science has led to many algorithms which have been proposed to solve these problems in the area of mathematics, economics and computer simulation. Ashtiani used Lemke algorithm for the first time to solve Linear Complementarity Problems in his algorithm for solving Traffic Assignment problem. In this study, Projection Gauss-Seidel algorithm along with two other similar algorithms have been studied for solving Linear Complementarity Problems in Ashtiani Complementarity algorithm and the results are compared with Lemke algorithm. Also an analytical method has been proposed for solving specific... 

During the past decade the ever increasing volume of greenhouse gases due to fossil fuels consumption have made humans to seek for alternative, non-polluting fuels as an effective strategy to reduce pollution and prevent environmental issues thereof. Electric cars are today known as one of the most effective solutions for this purpose. Of course, transition from gasoline-powered cars to electric cars in a wide scale is not technically possible in short term due to technological and infrastructural limitations. As a result, this lengthy process would lead to emergence of a combinational transportation system including both gas and electric-powered vehicles. The major differences between these... 

Cordon pricing is one of the methods for charging transportation network. In a cordon based pricing scheme, users who want to drive into the congested area of city and pass some special links which form the cordon, have to pay toll. The most important things in this method of pricing are finding the appropriate links which can shape the cordon and determining the tool level. This study, investigates an algorithm to find the optimal cordon location and toll level simultaneously in order to maximize social welfare. At first, assuming that cordon location is fixed and links that form the cordon are identified, a golden section method has been proposed for finding the optimal toll level. Then,... 

Accurate and realistic forecasts of traffic pattern in the networks can affect many decisions of urban transportation planning. In recent years, traffic assignment (TA) using stochastic models have received more attention by researchers of this field. Stochastic approach of route choice modeling using random utility theory has specifically developed to relax restrictive assumptions of traditional deterministic model and to address randomness nature of travelerʼs behavior. Together with development of discrete choice theory, more advanced models have been utilized to better represent route choice behavior. Although there have been considerable researches in the context of stochastic traffic... 

Nowadays the increasing congestion in transportation networks has made the managerial methods for controlling the congestion more important. Cordon pricing is one of the managerial means for reducing congestion. Therefore, accurate modeling methods that are consistent with reality and efficient traffic assignment algorithms play important roles in solving this problem. In this research several multiclass traffic assignment algorithms were examined and simultaneous complementarity algorithm was recognized to be able to yield equilibrium solution faster than other algorithms examined in this study. The aim of this thesis was also to analyze the effects of cordon pricing on networks with... 

Limited oil resources, increasing rate of oil consumption, and environmental concerns related to burning fossil fuels promote the use of alternative fuel vehicles. Electric vehicles are common among alternative fuel vehicles which decrease greenhouse gases emission and fossil fuel dependence. To increase electric vehicle market share, some challenges need to be overcome including range anxiety. Limited driving range is one of the main challenges for battery-powered electric vehicles. The distance limit inevitably changes electric vehicle drivers’ travel behavior. Given the scarcity of charging stations, consumers perceive this driving range limit to be a potential worry. Therefore,... 

Inappropriate use of the transportation networks is one of the causes of network congestion. Toll pricing is one of the traffic management tools to mitigate delay and congestion by guiding traffic flow to proper time and route. Efficient use of network facilities is one of transportation planners’ goal and highways are one of the most important facilities in a transportation network. In this study, we investigate the highway toll pricing problem in order to reduce total travel time for the users. We introduce four different strategies to collect toll from highway users. Direct solution methods for large networks faced with the problem of solving time. In this regard, some heuristics methods... 

One of the problems presently facing the world’s major cities is transportation network congestion. Managing transportation system with costs far less than construction or expansion of the network is one general approach to reduce traffic congestion. In this context, conversion of some regular lanes to special lanes for High Occupancy Vehicles (HOV) and studying the effectiveness of this management policy is a matter of importance. The aim of the present study is to evaluate the effects of HOV lanes on network traffic and travel demand. For this purpose several networks with two classes of vehicles are used that have been modeled as a linear complementarity problem. The effectiveness of this... 

Traffic assignment is a crucial part of transportation system management. Refining traffic assignment results by applying different side constraints have been the focus of many studies. Path side constraint was first introduced and studied for electric vehicles and the
corresponding traffic assignment problem was solved by a method based on the wellknown Frank-Wolf algorithm. In this study a new solution method based on complementarity algorithm has been proposed which is capable of solving traffic assignment problem with path side constraint in real sized networks. Length side constraint is considered in Sioux Falls network to compare two algorithms from the computational time point of... 

Nonstop growth of environmental concerns regarding ordinary vehicles detrimental effects have led to increasing use of Electrical Vehicles which require more researches in different fields of study. The main purpose of this study is solving the problem of Electrical Vehicles' traffic assignment considering recharging time as a function of amount of charge. Existing EVs have limited driving range, and these cars' drivers usually have to spend a considerable amount of time on recharging in order to complete a path. As a result, their corresponding optimum route choice differs from that of gasoline-based vehicles' drivers. In more detail, this study proposes an algorithm to solve the shortest... 

Shipment of hazardous materials has got an important role in the world of today. Nowadays, sustainable development has got serious attention, and human health and environment are one of the sustainable development bases. The risk of hazardous materials for human health and environment, and also importance of this kind of materials in the industrial economy, make necessity of programming for shipment of hazardous materials more serious. This thesis, presents an optimiziation model for routing and scheduling for shipment of hazardous materials. This model is a multi criteria time varing mixed integer programming (MIP). The presented model, finds the optimal routs and scheduling of movement... 

The toll pricing problem has been investigated in the literature for the cases of link, cordon, and facility (bridge, tunnel and etc.) pricing. Taking advantages of new technologies, nowadays it is possible to track the path of individual vehicles and collect the tolls by means of electronic devices. In this regard, we concerned the problem of path pricing. In this thesis, a variety of models for path pricing is proposed, the models are solved for the Hearn network and the results are compared to the results of link pricing models. In addition to the models, one exact solution method and two heuristic methods are proposed for the model of path pricing with the minimum total toll.... 

Wardrop’s first principle for defining the equilibrium flow in transportation networks is one of the mostly accepted assumptions in traffic assignment models. Optimization Models, Variational Inequalities, and Complementarity Equations are among the known models based on this assumption. In these models with the assumption of unlimited capacity for the network’s arcs and use of nonlinear cost functions, the constraint of arc capacity is considered implicitly. Another approach is to consider the arc capacity, explicitly. In recent decade this approach was the subject of some researches. In this thesis, these researches will be discussed. Then, researches about explicit consideration of the... 

Discrete network design problem is selecting a set of feasible projects among a set of candidate projects, considering a budget constraint in which user's cost is being minimized. Network design problem is one of the complicated problems in transportation science, since it is a bi-level problem in which the lower level is a traffic assignment problem and the upper level is finding the best set of arcs. Meta-heuristic algorithms can be used to solve this problem. Although, there is no guarantee to find the optimal solution by Meta-heuristic algorithms, but they find good solutions in short times. The purpose of this study is comparing the efficiency of three Meta-heuristic algorithms for... 

In recent years, traffic assignment problem with side constraints has been considered because of the importance of transportation supply management. Side constraints which are appeared due to imposing the traffic control policies are usually represented in form of link, node or district capacity constraints. Although link capacity constraint has been extensively studied, only a few papers on the other types of constraints such as capacity constraint on inflow to a district of city exist in the literature. In this research a method based on dynamic penalty function (DPF) is presented to solve traffic assignment problem with side constraints. Solution algorithm has been coded in a programming... 

In the transportation litreture, many different algorithms have been proposed for solving traffic assignment problem based on the user-equilibrium principal.These algorithms are devided into two main groups: Path-based algorithms and arc-based algorithms. In the past, arc-based algorithms has attracted quite attention, but recent scientific progress in the computer science changed this viewpoint to the state of path-based algorithms. Much of the attention has been focused on three particular algorithms: the complementarity (C) algorithm, the gradient projection (GP) algorithm and the disaggregate simplicial decomposition (DSD) algorithm. In this thesis, these three algorithms have been... 

Multicommodity network flow problem arises in the areas of transportation, logistics, and, telecommunication. The cost of each arc might be a linear or nonlinear function of the sum of commodity flows on that arc. Most of researches have worked on linear multicommodity flow problem. In addition, they consider the shared capacity constraints as the side constraints. In this thesis, we present a penalty-based algorithm for solving the multicommodity network flow problem with a linear or nonlinear objective function and considering the shared capacity constraints as the side. To solve multicommodity network flow problem, we relax the shared capacity constraints, and add a penalty term for the... 

Improving synchronization in a bus network has a profound effect on reducung waiting times and increasing satisfaction of system’s users. By doing so, the scheduler create a more attractive transit system that generates the opportunity for increasing the number of riders. In this research, the problem of creating timetables with maximum synchronization is modeled as a mixed integer programing (MIP) problem. The objective of this model is to minimize the total waiting times of passengers at transfer nodes. For this purpose, the model take advantage of uneven headways. Some of features that distinguish this research are more realistic objective function, and considering adjacent departures... 

In this dissertation, transportation networks with two classes of vehicles, including conventional vehicles and autonomous vehicles, have been studied. Four problems, including traffic assignment problem with two classes, congestion pricing problem for conventional vehicles, network design problem for autonomous vehicles, and simultaneous congestion pricing and network design problem, have been modeled and algorithms to solve them are presented. In this study, a dynamic penalty function algorithm is used to solve the congestion pricing problem, and a heuristic algorithm is used to solve the network design problem. Besides, the two-class traffic assignment problem is solved using the... 

In a discrete network design problem (DNDP), an optimal set of projects is chosen from suggested projects to expand a transportation network. The optimal set is selected by minimizing the total travel time with respect to the budget constraint. This problem is formulated as a bi-level optimization. In the current study, traffic assignment is solved at the lower level as a user equilibrium problem by considering the delay of intersections which is the major portion of total intra-city travel time. This study investigates the performance of the transportation network with more realistic assumptions compared to the previous studies in the network design problem.This study uses the branch and...