Sharif Digital Repository

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... 

Time-dependent origin-destination demand is a key input in dynamic traffic assignment in advanced traffic management systems, and the result of dynamic traffic assignment is dependent on the accuracy of this information. One method to achieve time dependent demand matrices is using a primary demand matrix and volume traffic counts in some links of network. In this thesis a bi-level model is used to correct the demand matrix and the extended gradient method is suggested to solve the problem. The extended gradient is an iterative method that in each iteration, corrects the demand matrix in a way that the estimated traffic flow be close to the observed traffic flow. Execution of this method in... 

A large amount of travel time in urban travels, is caused by intersection delays. Considering the intersection delay in traffic assignment, leads to more accurate network travel time and equilibrium flow pattern. Most traffic assignment softwares, consider unsignalized intersection delay as a constant or as a function of traffic volume on entering link, however, unsignalized intersection delay is a function of traffic volumes on all entering links. One of the reasons for these functions rarely being used in traffic assignments is that there is a lack of multi-variable delay function in transportation literature, and that most traffic assignment algorithms can not consider these functions.... 

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,... 

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... 

Traffic congestion is one of the most important issues facing modern societies that causes many impacts such as environmental pollutions and waste of physical and spiritual energies. One of the traffic congestion mitigation strategies is network management, which encompasses a diverse range of tools. Efficient management of urban transportation network requires the transportation network information. Traffic equilibrium in the transportation network is one of the fundamental information that is required for most of network management tools. In this study, a multi-modal traffic assignment model with complementarity structure is proposed that can determine the multi-modal traffic equilibrium... 

Signal coordination is one of the strategies to decrease the delay times in transportation networks. The application of dynamic traffic assignment has been made possible the modeling of flow loading in network links, and queue formation and dissipation in signalized intersections. In this thesis, signal offset set which produce the minimum total travel time in a network is determined, using a cell-based dynamic traffic assignment which is based on the cell transmission model. Genetic algorithm has been implemented to reach the suboptimal offset set. The application of the algorithm on a small test network shows that it can reach to an offset set with 1% error to the optimal offset set, by... 

Battery Electric vehicles (BEVs) are turning into a more well known type of transportation because of their energy effectiveness, further sustainability, and the arrangement of government support through motivation programs. However, BEVs have a constrained driving range due to their limited battery capacity. This limited battery capacity leads to a fear of exhausting energy in the middle of route which is referred to as range anxiety. The range anxiety affects BEV users’ travel choices such as route choice. Hence, BEV users should consider their vehicles’ remaining range while trying to minimize their travel times. This concern consequently changes the equilibrium flow on the transportation... 

Selfish route choice behaviors in user equilibrium could lead to some adverse impacts like: increase other's travel times, intensify air pollution, and add to risk of accidents. With regard to these unfavorable consequences, various congestion pricing policies as an economic-based solution have received adequate attention among both scholars and decision makers. A pricing scheme is called pareto improving congestion pricing, if at least one user’s travel time would be better off and no one being worst off. In Transportation literature, this problem is modeled as a mathematical program with complementarity constraints (MPCC) which is a sort of serious challenging optimization problem. In this... 

With the arrival of autonomous vehicles in the fleet of the transportation network and the change of some travel parameters such as travel time, mode choice models, as well as route choice models, will also change. These types of vehicles will be able to move less distance from the front vehicle compared to regular vehicles. Also, due to the exchange of information between the vehicle and the infrastructure, we will see an increase in the capacity of the transportation network and its safety. The period of complete transition from regular vehicles to self-driving vehicles will be relatively important and therefore it is necessary to see these two phenomena together. It is assumed that... 

Pricing problem in transportation networks focuses on determining tolls that cause travellers, motivated only by their travel costs, to choose routes that would collectively benefit all travellers and results in optimal utilization of transport network resources.This thesis addresses the toll pricing problem in which the objective is to minimize the number of required toll facilities in a transportation network. Minimum tollbooth problem (MINTB) has binary variables and is very difficult to solve. In this thesis a new heuristic approach has been presented for solving MINTB problem. The results show that, this approach is much faster than the existing algorithms and is able to solve real size... 

Nowadays, the necessity of management tools for controlling the ever increasing congestions in transportation networks has been increased. Pricing is one of these tools for mitigating congestions in transportation networks. In this regard, different pricing models have been developed for transportation networks. By considering the advancement in technologies and possibility of recording the vehicles’ traveled distance in the tolling areas, the amount of toll each user pays could be a nonlinear function of the distance traveled inside tolling areas. As a result, the generalized travel cost of each path may not be link-wise additive; therefore, the resulting shortest path problem cannot be... 

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...