Abstract:This paper presents a decomposition scheme to find near‐optimal solutions to a cell transmission model‐based system optimal dynamic traffic assignment problem with multiple origin‐destination pairs. A linear and convex formulation is used to define the problem characteristics. The decomposition is designed based on the Dantzig–Wolfe technique that splits the set of decision variables into subsets through the construction of a master problem and subproblems. Each subproblem includes only a single origin‐destina… Show more
“…The analytical approach (e.g., Jiang & Xie, 2014;Mounce & Carey, 2011;Wang, Szeto, Han, & Friesz, 2018) is very accurate but can only be applied in practice to small networks with few ODs. Several studies proposed exact decomposition techniques to reduce the computational complexity of the traffic assignment problems in static (Jafari, Pandey, & Boyles, 2017) and dynamic cases (Mehrabipour, Hajibabai, & Hajbabaie, 2019). However, congestion patterns are almost intractable analytically due to multiple nonlinear interactions inside the network (Taale & Pel, 2015).…”
Solving a dynamic traffic assignment problem in a transportation network is a computational challenge. This study first reviews the different algorithms in the literature used to numerically calculate the user equilibrium (UE) related to dynamic network loading. Most of them are based on iterative methods to solve a fixed-point problem.Two elements must be computed: the path set and the optimal path flow distribution between all origin-destination pairs. In a generic framework, these two steps are referred to as the outer and the inner loops, respectively. The goal of this study is to assess the computational performance of the inner loop methods that calculate the path flow distribution for different network settings (mainly network size and demand levels). Several improvements are also proposed to speed up convergence: four new swapping algorithms and two new methods for the step size initialization used in each descent iteration. All these extensions significantly reduce the number of iterations to obtain a good convergence rate and drastically speed up the overall simulations. The results show that the performance of different components of the solution algorithm is sensitive to the network size and saturation. Finally, the best algorithms and settings are identified for all network sizes with particular attention being given to the largest scale.
“…The analytical approach (e.g., Jiang & Xie, 2014;Mounce & Carey, 2011;Wang, Szeto, Han, & Friesz, 2018) is very accurate but can only be applied in practice to small networks with few ODs. Several studies proposed exact decomposition techniques to reduce the computational complexity of the traffic assignment problems in static (Jafari, Pandey, & Boyles, 2017) and dynamic cases (Mehrabipour, Hajibabai, & Hajbabaie, 2019). However, congestion patterns are almost intractable analytically due to multiple nonlinear interactions inside the network (Taale & Pel, 2015).…”
Solving a dynamic traffic assignment problem in a transportation network is a computational challenge. This study first reviews the different algorithms in the literature used to numerically calculate the user equilibrium (UE) related to dynamic network loading. Most of them are based on iterative methods to solve a fixed-point problem.Two elements must be computed: the path set and the optimal path flow distribution between all origin-destination pairs. In a generic framework, these two steps are referred to as the outer and the inner loops, respectively. The goal of this study is to assess the computational performance of the inner loop methods that calculate the path flow distribution for different network settings (mainly network size and demand levels). Several improvements are also proposed to speed up convergence: four new swapping algorithms and two new methods for the step size initialization used in each descent iteration. All these extensions significantly reduce the number of iterations to obtain a good convergence rate and drastically speed up the overall simulations. The results show that the performance of different components of the solution algorithm is sensitive to the network size and saturation. Finally, the best algorithms and settings are identified for all network sizes with particular attention being given to the largest scale.
“…Javani B proposed an OD based on the algorithm for static traffic assignment with fixed OD demand, which is tested in Chicago and Philadelphia [7]. Mehrabipour M proposed a multi OD algorithm based on the cell transmission model, which can optimize the dynamic traffic assignment of the system [8]. Hoang N H proposed a new linear programming framework, which uses the relationship between UE (user equilibrium) and the system optimal solution to solve the dynamic traffic assignment problem [9].…”
Section: Introductionmentioning
confidence: 99%
“…Direction and stations of Nanjing metro lines 15,14,13,12,11,10,9,8,7,6,5,41,42,43,44,45,46,47,48,49,50,. 51, 52, 53, 54, 55] …”
The information level of the urban public transport system is constantly improving, which promotes the use of smart cards by passengers. The OD (origination–destination) travel time of passengers reflects the temporal and spatial distribution of passenger flow. It is helpful to improve the flow efficiency of passengers and the sustainable development of the city. It is an urgent problem to select appropriate indexes to evaluate OD travel time and analyze the correlation of these indexes. More than one million OD records are generated by the AFC (Auto Fare Collection) system of Nanjing metro every day. A complex network method is proposed to evaluate and analyze OD travel time. Five working days swiping data of Nanjing metro are selected. Firstly, inappropriate data are filtered through data preprocessing. Then, the OD travel time indexes can be divided into three categories: time index, complex network index, and composite index. Time index includes use time probability, passenger flow between stations, average time between stations, and time variance between stations. The complex network index is based on two models: Space P and ride time, including the minimum number of rides, and the shortest ride time. Composite indicators include inter site flow efficiency and network flow efficiency. Based on the complex network model, this research quantitatively analyzes the Pearson correlation of the indexes of OD travel time. This research can be applied to other public transport modes in combination with big data of public smart cards. This will improve the flow efficiency of passengers and optimize the layout of the subway network and urban space.
“…In this game theory approach residual energy of each node plays important role in making game decisions. Mehrabipour et al [44] presented a decomposition scheme to find near-optimal solutions for a cell transmission modelbased system for an optimal dynamic traffic assignment problem with multiple origin-destination pairs. This technique decomposes the original problem into a set of subproblems.…”
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