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  • 1.
    Allström, Andreas
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Barceló, Jaume
    Department of Statistics and Operations Research, Universitat Politècnica de Catalunya.
    Ekström, Joakim
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Grumert, Ellen
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Gundlegård, David
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Rydergren, Clas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Traffic management for smart cities2017In: Designing, developing, and facilitating smart cities: urban design to IoT solutions. Part III / [ed] Vangelis Angelakis, Elias Tragos, Henrich C. Pöhls, Adam Kapovits and Alessandro Bassi, Switzerland: Springer, 2017, p. 211-240Chapter in book (Other academic)
    Abstract [en]

    Smart cities, participatory sensing as well as location data available in communication systems and social networks generates a vast amount of heterogeneous mobility data that can be used for traffic management. This chapter gives an overview of the different data sources and their characteristics and describes a framework for utilizing the various sources efficiently in the context of traffic management. Furthermore, different types of traffic models and algorithms are related to both the different data sources as well as some key functionalities of active traffic management, for example short-term prediction and control.

  • 2.
    Allström, Andreas
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology. Sweco TransportSystem, Stockholm, Sweden.
    Bayen, Alexandre M.
    University of California Berkeley, USA.
    Fransson, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology. Sweco TransportSystem, Stockholm, Sweden.
    Gundlegård, David
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Patire, Anthony D.
    University of California Berkeley, USA.
    Rydergren, Clas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Sandin, Mats
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Calibration Framework based on Bluetooth Sensors for Traffic State Estimation Using a Velocity based Cell Transmission Model2014In: Transportation Research Procedia, ISSN 2352-1465, Vol. 3, p. 972-981Article in journal (Refereed)
    Abstract [en]

    The velocity based cell transmission model (CTM-v) is a discrete time dynamical model that mimics the evolution of the traffic velocity field on highways. In this paper the CTM-v model is used together with an ensemble Kalman filter (EnKF) for the purpose of velocity sensor data assimilation. We present a calibration framework for the CTM-v and EnKF. The framework consists of two separate phases. The first phase is the calibration of the parameters of the fundamental diagram and the second phase is the calibration of demand and filter parameters. Results from the calibrated model are presented for a highway stretch north of Stockholm, Sweden.

  • 3.
    Allström, Andreas
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Ekström, Joakim
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Gundlegård, David
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Ringdahl, Rasmus
    Linköping University, Department of Science and Technology, Communications and Transport Systems.
    Rydergren, Clas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Bayen, Alexandre M.
    Department of Civil and Environmental Engineering, University of California.
    Patire, Anthony D.
    Department of Civil and Environmental Engineering, University of California.
    A hybrid approach for short-term traffic state and travel time prediction on highways2016In: TRB 95th annual meeting compendium of papers, 2016Conference paper (Refereed)
    Abstract [en]

    Traffic management and traffic information are essential in urban areas, and require a good knowledge about both the current and the future traffic state. Both parametric and non-parametric traffic state prediction techniques have previously been developed, with different advantages and shortcomings. While non-parametric prediction has shown good results for predicting the traffic state during recurrent traffic conditions, parametric traffic state prediction can be used during non-recurring traffic conditions such as incidents and events. Hybrid approaches, combining the two prediction paradigms have previously been proposed by using non-parametric methods for predicting boundary conditions used in a parametric method. In this paper we instead combine parametric and non-parametric traffic state prediction techniques through assimilation in an Ensemble Kalman filter. As non-parametric prediction method a neural network method is adopted, and the parametric prediction is carried out using a cell transmission model with velocity as state. The results show that our hybrid approach can improve travel time prediction of journeys planned to commence 15 to 30 minutes into the future, using a prediction horizon of up to 50 minutes ahead in time to allow the journey to be completed.

  • 4.
    Allström, Andreas
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Ekström, Joakim
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Gundlegård, David
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Ringdahl, Rasmus
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Rydergren, Clas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Bayen, Alexandre M.
    Department of Civil and Environmental Engineering, University of California, Berkeley, CA, USA.
    Patire, Anthony D.
    Department of Civil and Environmental Engineering, University of California, Berkeley, CA, USA.
    Hybrid Approach for Short-Term Traffic State and Travel Time Prediction on Highways2016In: Transportation Research Record, ISSN 0361-1981, E-ISSN 2169-4052, Vol. 2554, p. 60-68Article in journal (Refereed)
    Abstract [en]

    Traffic management and traffic information are essential in urban areas and require reliable knowledge about the current and future traffic state. Parametric and nonparametric traffic state prediction techniques have previously been developed with different advantages and shortcomings. While nonparametric prediction has shown good results for predicting the traffic state during recurrent traffic conditions, parametric traffic state prediction can be used during nonrecurring traffic conditions, such as incidents and events. Hybrid approaches have previously been proposed; these approaches combine the two prediction paradigms by using nonparametric methods for predicting boundary conditions used in a parametric method. In this paper, parametric and nonparametric traffic state prediction techniques are instead combined through assimilation in an ensemble Kalman filter. For nonparametric prediction, a neural network method is adopted; the parametric prediction is carried out with a cell transmission model with velocity as state. The results show that the hybrid approach can improve travel time prediction of journeys planned to commence 15 to 30 min into the future, with a prediction horizon of up to 50 min ahead in time to allow the journey to be completed

  • 5.
    Allström, Andreas
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Gundlegård, David
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Rydergren, Clas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Evaluation of travel time estimation based on LWR-v and CTM-v: A case study in Stockholm2012In: 15th International IEEE Conference on Intelligent Transportation Systems (ITSC), 2012, Piscataway, N.J, USA: IEEE , 2012, p. 1644-1649Conference paper (Refereed)
    Abstract [en]

    Real-time estimations of current and future traffic states are an essential part of traffic management and traffic information systems. Within the Mobile Millennium project considerable effort has been invested in the research and development of a real-time estimation system that can fuse several sources of data collected in California. During the past year this system has been adapted to also handle traffic data collected in Stockholm. This paper provides an overview of the model used for highways and presents results from an initial evaluation of the system. As part of the evaluation process, GPS data collected in an earlier field-test and estimations generated by the existing system used by the TMC in Stockholm, are compared with the estimations generated by the Mobile Millennium system. Given that the Mobile Millennium Stockholm system has not undergone any calibration, the results from the evaluation are considered promising. The estimated travel times correspond well to those measured in the field test. Furthermore, the estimations generated by the Mobile Millennium system can be regarded as superior to those of existing traffic management system in Stockholm. The highway model was found to perform well even with a reduction in the number of sensors providing data. The findings of this study indicate the robustness of the Mobile Millennium system and demonstrate how the system can be migrated to other geographical areas with similar sources of available data.

  • 6.
    Angelakis, Vangelis
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Gundlegård, David
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Rydergren, Clas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Rajna, Botond
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Vrotsou, Katerina
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Carlsson, Richard
    Ericsson Research, Services & Software.
    Forgeat, Julien
    Ericsson Research, Services & Software.
    Hu, Tracy H
    Ericsson Research, Services & Software.
    Liu, Evan L
    Ericsson Research, Services & Software.
    Moritz, Simon
    Ericsson Research, Services & Software.
    Zhao, Sky
    Ericsson Research, Services & Software.
    Zheng, Yaotian
    Ericsson Research, Services & Software.
    Mobility modeling for transport efficiency: Analysis of travel characteristics based on mobile phone data2013In: Netmob 2013: Mobile phone data for development / [ed] Vincent Blondel, 2013Conference paper (Refereed)
    Abstract [en]

    Signaling data from the cellular networks can provide a means of analyzing the efficiency of a deployed transportation system and assisting in the formulation of transport models to predict its future use. An approach based on this type of data can be especially appealing for transportation systems that need massive expansions, since it has the added benefit that no specialized equipment or installations are required, hence it can be very cost efficient.

    Within this context in this paper we describe how such obtained data can be processed and used in order to act as enablers for traditional transportation analysis models. We outline a layered, modular architectural framework that encompasses the entire process and present results from initial analysis of mobile phone call data in the context of mobility, transport and transport infrastructure. We finally introduce the Mobility Analytics Platform, developed by Ericsson Research, tailored for mobility analysis, and discuss techniques for analyzing transport supply and demand, and give indication on how cell phone use data can be used directly to analyze the status and use of the current transport infrastructure.

  • 7.
    Breyer, Nils
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Gundlegård, David
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Rydergren, Clas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Bäckman, Johan
    Former Tele2.
    Trip extraction for traffic analysis using cellular network data2017In: 5th IEEE International Conference on Models and Technologies for Intelligent Transportation Systems (MT-ITS) / [ed] IEEE Italy Section, Naples: IEEE Press, 2017, p. 321-326Conference paper (Refereed)
    Abstract [en]

    To get a better understanding of people’s mobility, cellular network signalling data including location information, is a promising large-scale data source. In order to estimate travel demand and infrastructure usage from the data, it is necessary to identify the trips users make. We present two trip extraction methods and compare their performance using a small dataset collected in Sweden. The trips extracted are compared with GPS tracks collected on the same mobiles. Despite the much lower location sampling rate in the cellular network signalling data, we are able to detect most of the trips found from GPS data. This is promising, given the relative simplicity of the algorithms. However, further investigation is necessary using a larger dataset and more types of algorithms. By applying the same methods to a second dataset for Senegal with much lower sampling rate than the Sweden dataset, we show that the choice of the trip extraction method tends to be even more important when the sampling rate is low. 

  • 8.
    Breyer, Nils
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Rydergren, Clas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Gundlegård, David
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Cellpath Routing and Route Traffic Flow Estimation Based on Cellular Network Data2018In: The Journal of urban technology, ISSN 1063-0732, E-ISSN 1466-1853, no 2, p. 85-104Article in journal (Refereed)
    Abstract [en]

    The signaling data in cellular networks provide means for analyzing the use of transportation systems. We propose methods that aim to reconstruct the used route through a transportation network from call detail records (CDRs) which are spatially and temporally sparse. The route estimation methods are compared based on the individual routes estimated. We also investigate the effect of different route estimation methods when employed in a complete network assignment for a larger city. Using an available CDR dataset for Dakar, Senegal, we show that the choice of the route estimation method can have a significant impact on resulting link flows.

  • 9.
    Connors, Richard
    et al.
    Institute for Transport Studies, Leeds University, Leeds, England, UK.
    Patriksson, Michael
    Department of Mathematical Sciences, Chalmers University of Technology, Gothenburg, Sweden.
    Rydergren, Clas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Sumalee, Agachai
    King Mongkut’s Institute of Technology Ladkrabang, Thailand.
    Watling, David
    Institute for Transport Studies, Leeds University, Leeds, England, UK.
    Sensitivity Analysis of Welfare, Equity, and Acceptability Level of Transport Policies2015In: Optimization, Control, and Applications in the Information Age: In Honor of Panos M. Pardalos’s 60th Birthday / [ed] Athanasios Migdalas, Athanasia Karakitsiou, London: Springer Publishing Company, 2015, p. 39-65Chapter in book (Refereed)
    Abstract [en]

    Transport planners face a major challenge to devise policies to meet multiple expectations and objectives. While we know that transport networks are complex, multi-modal, and spatially distributed systems, there is now a long history of mathematical tools which assist planners in understanding travel movements. However, the objectives that they are asked to achieve do not always admit such a quantification, and so there is a potential mismatch between seemingly qualitatively driven objectives and quantitatively expressed models of the transport system. In the present chapter we address this mismatch, by focusing on three objectives that we believe represent the typical interests of a planner. These are namely: is the policy economically justifiable (efficient), is it “fair” (equitable), and is it justifiable to a democratic society (acceptable)? We provide mathematical representations of these three objectives and link them to mathematical theory of transport networks, in which we may explore the sensitivity of travel behaviour (and hence the objectives) to various multi-modal transport policies. The detailed steps for representing the policy objectives and sensitivities in the network are set out, and the results of a case study reported in which road tolls, road capacities, and bus fares are the policy variables. Overall, the chapter sets out a systematic method for planners to choose between multi-modal policies based on these three objectives.

  • 10.
    Daneva (Mitradjieva), Maria
    et al.
    Linköping University, Department of Mathematics, Optimization . Linköping University, The Institute of Technology.
    Göthe-Lundgren, Maud
    Linköping University, Department of Mathematics, Optimization . Linköping University, The Institute of Technology.
    Larsson, Torbjörn
    Linköping University, Department of Mathematics, Optimization . Linköping University, The Institute of Technology.
    Patriksson, Michael
    Mathematical Sciences, Chalmers University of Technology and Göteborg University, Gothenburg, Sweden.
    Rydergren, Clas
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    A Sequential Linear Programming Algorithm with Multi-dimensional Search: Derivation and Convergence2007Article in journal (Other academic)
    Abstract [en]

    We present a sequential linear programming, SLP, algorithm in which the traditional line-search step is replaced by a multi-dimensional search. The algorithm is based on inner approximations of both the primal and dual spaces, which yields a method which in the primal space combines column and constraint generation. The algorithm does not use a merit function, and the linear programming subproblem of the algorithm differs from the one obtained in traditional methods of this type, in the respect that linearized constraints are taken into account only implicitly in a Lagrangiandual fashion. Convergence to a point that satisfies the Karush-Kuhn-Tucker conditions is established. We apply the new method to a selection of the Hoch-Schittkowski’s nonlinear test problems and report a preliminary computational study in a Matlab environment. Since the proposed algorithmcombines column and constraint generation, it should be advantageous with large numbers of variables and constraints.

  • 11.
    Daneva (Mitradjieva), Maria
    et al.
    Linköping University, Department of Mathematics, Optimization . Linköping University, The Institute of Technology.
    Larsson, Torbjörn
    Linköping University, Department of Mathematics, Optimization . Linköping University, The Institute of Technology.
    Patriksson, Michael
    Mathematical Sciences, Chalmers University of Technology and Göteborg University, Gothenburg, Sweden.
    Rydergren, Clas
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    A Comparison of Feasible Direction Methods for the Stochastic Transportation Problem2010In: Computational optimization and applications, ISSN 0926-6003, E-ISSN 1573-2894, Vol. 46, no 3, p. 451-466Article in journal (Refereed)
    Abstract [en]

    The feasible direction method of Frank and Wolfe has been claimed to be efficient for solving the stochastic transportation problem. While this is true for very moderate accuracy requirements, substantially more efficient algorithms are otherwise diagonalized Newton and conjugate Frank–Wolfe algorithms, which we describe and evaluate. Like the Frank–Wolfe algorithm, these two algorithms take advantage of the structure of the stochastic transportation problem. We also introduce a Frank–Wolfe type algorithm with multi-dimensional search; this search procedure exploits the Cartesian product structure of the problem. Numerical results for two classic test problem sets are given. The three new methods that are considered are shown to be superior to the Frank–Wolfe method, and also to an earlier suggested heuristic acceleration of the Frank–Wolfe method.

  • 12.
    Ekström, Joakim
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Engelson, Leonid
    Centre for Traffic Research KTH.
    Rydergren, Clas
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    A heuristic method for finding congestion pricing schemes in transportation networks with modal choice2008In: International conference of Hong Kong society for transportation studies,2008 / [ed] Lo, HP; Leung, SCH; Tam, SML, Hong Kong, China: Hong Kong Society of Transportation Studies Ltd. , 2008, p. 773-782Conference paper (Refereed)
    Abstract [en]

     In this paper we extend a previously developed heuristic procedure, with a modal choice model, to solve the congestion pricing problem of simultaneously finding the optimal number of toll facilities, their corresponding location and toll levels. When considering a congestion pricing scheme the cost of collecting the tolls can not be disregarded. The objective is where-fore to maximize the net social surplus, which is the social surplus minus the cost of collect-ing the tolls. The heuristic method is an iterative solution procedure, in which the integer part of the objec-tive function is approximated by a continuous function. A version of the Sioux Falls network (76 links) is used to demonstrate the solution procedure. The solution is a congestion pricing scheme which divide the network into four zones, by locating tolls on 27 links. This solution yields a social surplus which is only 13.5% lower than the marginal social cost pricing solu-tion. 

  • 13.
    Ekström, Joakim
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Engelson, Leonid
    Centre for Traffic Research KTH.
    Rydergren, Clas
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Decision support for finding locations and toll levels within a congestion pricing scheme2007In: Kuhmo Nectar Conference,2007, 2007Conference paper (Other academic)
  • 14.
    Ekström, Joakim
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Engelson, Leonid
    Centre for Traffic Research KTH.
    Rydergren, Clas
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Decision support for finding locations and toll levels within a congestion pricing scheme2008In: Transportation Research Board Annual Meeting,2008, Washington D.C.: TRB , 2008Conference paper (Refereed)
    Abstract [en]

    Designing a congestion pricing scheme involves a number of complex decisions. Focusing on the quantitative parts of a congestion pricing system with link tolls, the problem involves finding the number of tolled links, the link toll locations and their corresponding toll level and schedule. In this paper, we develop and evaluate methods for finding a most efficient design of a congestion pricing scheme in a road network with elastic demand. The design efficiency is measured by the net social surplus, which is computed as the difference between the social surplus and the collection costs (i.e. setup and operation cost) of the congestion pricing system. The problem of finding such a scheme is stated as a combinatorial bi-level optimization problem. On the upper level we maximize the net social surplus and on the lower level we solve a user equilibrium problem with elastic demand, given the toll locations and toll levels, to simulate the user response. We modify a known heuristic procedure for finding the optimal locations and toll levels given a fixed number of tolls to locate, to find the optimal number of tolls to locate as well. A new heuristic procedure is also presented which is based on repeated solutions of a continuous approximation of the combinatorial problem. Numerical results for two small scale test networks are presented. Both methods perform satisfactory on the two networks. Comparing the two methods, the iterative approximation procedure is the one which shows the best results. The results are compared to solutions obtained by an exhaustive search.

  • 15.
    Ekström, Joakim
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Engelson, Leonid
    Centre for Traffic Research, Royal Institute of Technology.
    Rydergren, Clas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Heuristic algorithms for a second-best congestion pricing problem2009In: Netnomics, ISSN 1385-9587, E-ISSN 1573-7071, Vol. 10, no 1, p. 85-102Article in journal (Refereed)
    Abstract [en]

    Designing a congestion pricing scheme involves a number of complex decisions.Focusing on the quantitative parts of a congestion pricing system with link tolls, the problem involves findingthe number of toll links, the link toll locations and their corresponding toll level and schedule.In this paper, we develop and evaluate methods for finding the most efficient design for a congestion pricing scheme in a road network model with elastic demand. The design efficiency is measured by the net social surplus, which is computed as the difference between the social surplus and the collection costs (i.e. setup and operational costs) of the congestion pricing system. The problem of finding such a scheme is stated as a combinatorial bi-level optimization problem. At the upper level, we maximize the net social surplus and at the lower level we solve a user equilibrium problem with elastic demand, given the toll locations and toll levels,to simulate the user response. We modify a known heuristic procedure for finding the optimal locations and toll levels given a fixed number of tolls to locate, to find the optimal number of toll facilities as well. A new heuristic procedure, based on repeated solutions of a continuous approximation of the combinatorial problem is also presented. Numerical results for two small test networks are presented. Both methods perform satisfactorily on the two networks. Comparing the two methods, we find that the continuous approximation procedure is the one which shows the best results.

  • 16.
    Ekström, Joakim
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Engelson, Leonid
    Centre for Traffic Research, Royal Institute of Technology, Stockholm, Sweden.
    Rydergren, Clas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Optimal Toll Locations and Levels in Congestion Pricing Schemes: a Case Study of Stockholm2014In: Transportation planning and technology (Print), ISSN 0308-1060, E-ISSN 1029-0354, Vol. 37, no 4, p. 333-353Article in journal (Refereed)
    Abstract [en]

    As congestion pricing has moved from theoretical ideas in the literature to real world implementations, the need for decision support when designing the pricing schemes has become evident. This paper deals with the problem of finding optimal toll levels and locations in a road traffic network, and presents a case study of Stockholm. The optimization problem of finding optimal toll levels, given a predetermined cordon, and the problem of finding both optimal toll locations and levels are presented, and previously developed heuristics are used for solving these problems. For the Stockholm case study, the possible welfare gains of optimizing the toll levels in the current cordon, and optimizing both the toll locations and their corresponding toll levels are evaluated. It is shownthat by tuning the toll levels in the current congestion pricing cordon used in Stockholm, the welfare gain can be significantly increased, and furthermore improved by allowing a toll on the bypass highway “Essingeleden”. It is also shown that by optimizing both the toll locations and levels, a congestion pricing scheme with welfare gain close to what can be achieved by marginal social cost pricing, can be designed with tolls being located on only a forth of the tollable links.

  • 17.
    Ekström, Joakim
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems.
    Engelson, Leonid
    Royal Institute of Technology.
    Rydergren, Clas
    Linköping University, Department of Science and Technology, Communications and Transport Systems.
    TOWARDS OPTIMAL LOCATIONS AND TOLLLEVELS IN CONGESTION PRICING SCHEMES2009In: Proceedings of the 16th ITS World Congress, 2009Conference paper (Refereed)
    Abstract [en]

    This paper addresses the problem of designing a road congestion pricing scheme withlink tolls. The problem involves decisions on where to locate the toll collecting facilitiesand what tolls to charge the road users. We formulate this problem as a bi-levelprogram, with the objective to maximize the net social surplus, which include the costof setting up and operate the toll collection system. A previously developed heuristicmethod is applied to find close to optimal toll locations and charges for a traffic networkrepresenting the Stockholm region. The result is compared with the current congestionpricing scheme in Stockholm.

  • 18.
    Ekström, Joakim
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Rydergren, Clas
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Decision support for finding optimal locations and toll levels within a congestion pricing scheme2007In: Second Nordic Optimization Symposium,2007, 2007Conference paper (Other academic)
  • 19.
    Ekström, Joakim
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Rydergren, Clas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Why modeling of heavy goods vehicles matters when designing congestion pricing schemes2013Conference paper (Other academic)
    Abstract [en]

    Differentiated tolls for cars and heavy goods vehicles (HGVs) may improve the efficiency of congestion pricing schemes. Not only do private trips by car and commercial activities by HGV differ in how the time is valued by the user/operator, in general, one additional truck will also contribute to the congestion more than one additional car. In this paper we show how different modeling approaches for HGV route choice and demand may affect the evaluation of road pricing schemes. Also, we provide a small example to illustrate potential problems, and present results for a larger model of the German city Stuttgart.

  • 20.
    Ekström, Joakim
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Rydergren, Clas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Sumalee, Agachai
    The Hong Kong Polytechnic University, Department of Civil and Structural Engineering.
    Finding optimal toll locations and levels in elasticdemand networks: -A MILP approximation approach2010In: Proceedings of the Tristan VII Conference, 2010Conference paper (Refereed)
  • 21.
    Gundlegård, David
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Rydergren, Clas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Barcelo, Jaime
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Dokoohaki, Nima
    Swedish Institute of Computer Science.
    Hess, Andrea
    Swedish Institute of Computer Science.
    Görnerup, Olof
    Swedish Institute of Computer Science.
    Travel demand analysis with differential private releases2015In: Netmob 2015: Mobile phone data for development / [ed] Vincent Blondel, 2015Conference paper (Refereed)
    Abstract [en]

    The use of mobile phone data for planning of transport infrastructure has been shown to have great potential in providing a means of analyzing the efficiency of a transportation system and assisting in the formulation of transport models to predict its future use. In this paper we describe how this type of data can be processed and used in order to act as both enablers for traditional transportation analysis models, and provide new ways of estimating travel behavior. Specifically, we propose a technique for describing the travel demand by constructing time sliced origin destination matrices which respect the level of detail available in Call Detail Records (CDR) from mobile phone use.

    When analyzing large quantities of human mobility traces, the aspects of sensitivity of traces to be analyzed, and the scale at which such analysis can be accounted for is of high importance. The sensitivity implies that identifiable information must not be inferred from the data or any analysis of it. Thus, prompting the importance of maintaining privacy during or post-analysis stages. We aggregate the raw data with the goal to retain relevant information while at the same time discard sensitive user specifics, through site sequence clustering and frequent sequence extraction. These techniques have at least three benefits: data reduction, information mining, and anonymization. Further, the paper reviews the aggregation techniques with regard to privacy in a post-processing step.

    The approaches presented in the paper for estimation of travel demand and route choices, and the additional privacy analysis, build a comprehensive framework usable in the processing of mobile phone data for transportation planning.

    The project presented in this paper a part of the D4D-Senegal challenge.

  • 22.
    Gundlegård, David
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Rydergren, Clas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Breyer, Nils
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Rajna, Botond
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Travel demand estimation and network assignment based on cellular network data2016In: COMPUTER COMMUNICATIONS, ISSN 0140-3664, Vol. 95, p. 29-42Article in journal (Refereed)
    Abstract [en]

    Cellular networks signaling data provide means for analyzing the efficiency of an underlying transportation system and assisting the formulation of models to predict its future use. This paper describes how signaling data can be processed and used in order to act as means for generating input for traditional transportation analysis models. Specifically, we propose a tailored set of mobility metrics and a computational pipeline including trip extraction, travel demand estimation as well as route and link travel flow estimation based on Call Detail Records (CDR) from mobile phones. The results are based on the analysis of data from the Data for development "D4D" challenge and include data from Cote dlvoire and Senegal. (C) 2016 Elsevier B.V. All rights reserved.

  • 23.
    Larsson, Torbjörn
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mathematics, Optimization .
    Patriksson, Michael
    Matematiska vetenskaper Chalmers tekniska högskola.
    Rydergren, Clas
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    A column generation procedure for the side constrained traffic equilibrium problem2004Article in journal (Refereed)
    Abstract [en]

    We present a column generation procedure for the side constrained traffic equilibrium problem. A dual stabilization scheme is introduced to improve the computational performance. Computational experiments for the case of linear side constraints are presented. The test problems are well known traffic equilibrium instances where side constraints of link flow capacity type and general linear side constraints are added. The computational results are promising especially for instances with a relatively small number of side constraints.

  • 24.
    Larsson, Torbjörn
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mathematics, Optimization .
    Patriksson, Michael
    Rydergren, Clas
    Linköping University, Department of Science and Technology.
    Inverse nonlinear multicommodity flow optimization by column generation2003In: Optimization Methods and Software, ISSN 1055-6788, E-ISSN 1029-4937, Vol. 18, no 5, p. 601-613Article in journal (Refereed)
    Abstract [en]

    We present a solution algorithm for an inverse nonlinear multicommodity network flow problem. This problem is to find link cost adjustments that make a given target link flow solution optimal in a nonlinear multicommodity network flow problem, and that are optimal with respect to a specified objective. The solution procedure uses column generation. We present computational results for instances where the nonlinear multicommodity network flow problems are small and medium scale traffic equilibrium problems, and where system optimal link flows are targeted. The computational results show that the solution procedure is a viable approach for solving medium-scale instances of the inverse traffic equilibrium problem.

  • 25.
    Lundgren, Jan
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Peterson, Anders
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Rydergren, Clas
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    A heuristic for the estimation of time-dependent origin-destination matrices from traffic counts2005In: Advanded OR an AI Methods in Transportation, Proceedings of the 10th Jubilee Meeting of the EURO Working Group on Transportation,2005, Poznan, Poland: Publishing House of Poznan University of Technology , 2005, p. 242-Conference paper (Refereed)
  • 26.
    Lundgren, Jan T.
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Peterson, Anders
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Rydergren, Clas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    A Heuristic for the Estimation of Time-Dependent Origin Origin–Destination Matrices from Traffic Counts2007In: Nordic MPS ’04, Norrköping, Sweden, October 21–23, 2004 and The 10th Jubilee Meeting of the EURO Working Group on Transportation, Poznan, Poland, September 13–16, 2005 and Transportforum, Linköping, Sweden, January 11–12, 2006, 2007Conference paper (Refereed)
  • 27.
    Olstam, Johan
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering. Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Trafikanalys och logistik, TAL..
    Engelson, Leonid
    Trafikverket.
    Johansson, Lars
    Trafikverket.
    Rydergren, Clas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Nya restidsfunktioner med korsningsfördröjning2016Report (Other academic)
    Abstract [en]

    This report presents method and result for the development of new travel time functions for the Swedish national transport planning modelling system Sampers. Travel time functions include one part that describes the travel time delay on road links and one part that describes the delay at intersections. It is difficult and expensive to conduct synchronized measurements of traffic flow and travel times. An alternative approach has therefore been applied in which the travel time functions were calibrated based on calculations of intersection delay for different intersection designs using the intersection delay and capacity model Capcal. The travel time functions developed were tested and validated are now implemented in the Sampers system.

  • 28.
    Olstam, Johan
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Rydergren, Clas
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Matstoms, Pontus
    Swedish National Road and Transport Research Institute VTI.
    Estimation of Volume Delay Functions for Urban Environments Based on an Analytical Intersection Model2008In: Transportation Research Board 87th Annual Meeting,2008, Washington: Transportation Research Board , 2008Conference paper (Refereed)
    Abstract [en]

    This paper describes a method for estimating parameters in volume delay functions. The volume delay function is a central part of static traffic assignment models and describes how the travel time on road link changes with traffic demand. The proposed estimation method is based on that the volume delay function is divided into two parts, one part describing the link travel time and delay and one part describing the intersection delay. The parameters for the link and intersection parts are estimated separately. Collecting data for the link part is seldom a problem. However, earlier experiences have shown that it is both difficult and expensive to collect data on intersection delay. We have used an approach in which the intersection delay data is taken from a model for calculating intersection delay, in this case the analytical intersection model CAPCAL. The developed estimation method has been exemplified on one road type and road environment. A sensitivity analysis has been conducted in order to investigate how large influence that the different assumptions on the road factors have on the volume delay function. The conclusions are that the flow levels on the cross road, the intersection density, the share of straight forward traffic, and the share of different intersection types has the largest influence, and thus should be prioritized when collecting road type data. 

  • 29.
    Rydergren, Clas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Comparison of headway-based public transport models: Numerical experiments for Stockholm2013In: Public Transport, ISSN 1866-749X, E-ISSN 1613-7159, Vol. 5, no 3, p. 177-191Article in journal (Refereed)
    Abstract [en]

    In this paper we evaluate the output from four headway-based public transport model variants for modeling the public transports in Stockholm, Sweden. The results from the four models are analyzed and compared to trip observations. The comparisons are based on model instances where the parameters in the generalized travel time function are calibrated. The best possible parameter values have been found using the calibration procedures SPSA and Compass search. Two different objective functions have been evaluated for the calibration.

    Numerical experiments have been performed using a public transport model implemented in Visum by Storstockholms lokaltrafik. For the calibration and analysis, trip observations from the Swedish national travel survey and data generated from a public transport trip planner are used.

    From the numerical results, it is concluded that it is of less importance to find the best possible parameter values in the generalized cost function than selecting the best model variant. For the Stockholm public transport model, the numerical results indicate that the models in the class of Random departure time models result in a better fit to the observed trips than the models in the class of Optimal strategies.

  • 30.
    Rydergren, Clas
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Bellver Muñoz, Patricia
    ETRA I+D.
    Cats, Oded
    TU Delft.
    Törnquist Krasemann, Johanna
    BTH.
    Scarinci, Riccardo
    EPFL.
    Laumanns, Marco
    IBM Research.
    Unravelling travel flow dynamics: A multi-level analysis of public transport demand and passenger reliability2018Conference paper (Refereed)
    Abstract [en]

    Smart cities and communities rely on efficient, reliable and robust transport systems. Managing urban public transport systems is becoming increasingly challenging with a pronounced shift towards multiple actors operating in a multi-modal multi-level networks. This calls for the development of an integrated passenger-focused management approach which takes advantage of multiple data sources and state-of-the-art scheduling support. The TRANS-FORM project is developing, implementing and testing a data driven decision making tool that will support smart planning and proactive and adaptive operations. The tool will integrate new concepts and methods of behavioral modelling, passenger flow forecasting and network state predictions into real-time operations. In this study we present the first step in this direction which consists of an empirical analysis of passenger flows to infer travel patterns and service reliability properties. Data mining and transport flow analysis are used to investigate network dynamics at different scales.

  • 31.
    Rydergren, Clas
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Le Kieu, Minh
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Evaluation of Roundabout and Signalized Intersection Designs using Microsimulation2011Conference paper (Refereed)
  • 32.
    Rydergren, Clas
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Mendoza, Ivan
    KU Leuven, L-Mob, Leuven Mobility Research Center, CIB, Leuven, Belgium;Universidad del Azuay, Cuenca, Ecuador.
    Tampère, Chris MJ
    KU Leuven, L-Mob, Leuven Mobility Research Center, CIB, Leuven, Belgium.
    Discovering Regularity in Mobility Patterns to Identify Predictable Aggregate Supply for Ridesharing2018In: Transportation Research Record, ISSN 0361-1981, E-ISSN 2169-4052, Vol. 2672, p. 213-223Article in journal (Refereed)
    Abstract [en]

    Heterogeneous data collected by smartphone sensors offer new opportunities to study a person’s mobility behavior. The mobility patterns extracted from the travel histories found in these data enable agents residing in mobile devices to model transitions between visited locations, so that upcoming trips can be predicted after observing a set of events, and assistance can be planned in advance. When several agents cooperate, the forecasted trips made by multiple users can provide a potential supply for shared mobility systems such as dynamic ridesharing. These trips must be sufficiently regular and frequent to be reliably announced as shareable trips. This paper describes a methodology to identify a predictable aggregate supply for ridesharing via mobility patterns discovered in users’ travel histories. The methodology empirically quantifies measures like the regularity and frequency of these patterns on a dataset consisting of 967 users scattered across different geographical areas. The sample exhibits high heterogeneity with respect to these measures (hence, of predictability, regardless of the prediction method). This paper shows how frequency of trip patterns decreases, while regularity increases, when additional dimensions such as departure times are added to the analysis. It was concluded that the traveler flexibility with regard to accepting less regular trips is vital to discover a larger supply. These results provide insights to develop future applications able to take advantage of this approach, to increase ridesharing rates, allowing a critical mass to be more easily attained.

  • 33.
    Tapani, Andreas
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology. Statens väg- och transportforskningsinstitut (VTI).
    Rydergren, Clas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Modellering av stadstrafik med resekedjor som inkluderar cykel och andra färdmedel2013Conference paper (Other academic)
1 - 33 of 33
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