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  • 1.
    Lindberg, Therese
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering. VTI, Linköping, Sweden.
    Peterson, Anders
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Tapani, Andreas
    VTI, Linköping, Sweden.
    A simulation model for assessment and evaluation of busterminal design2018Conference paper (Other academic)
    Abstract [en]

    Interchange stations with their connections between modes and lines are central for a high quality public transport system. Bus access at the station needs to operate reliably and efficiently in order to prevent congestion and queues. Here, a discrete event simulation model of vehicle movements and interactions at bus terminals is developed and implemented. The model has a modular approach, where common spatial sections at terminals are represented by modules that can be combined into various terminal layouts. These modules describe the events a vehicle may go through in a particular section of the terminal, such as arriving to a bus stop or stopping at a traffic light at the exit. The model can be used in planning processes, both for new terminals and redesign of existing ones, and is able to describe the detailed movements and interactions between vehicles that occur at larger terminals. The model is tested in a numerical experiment representing Norrköping interchange station in Sweden. The experiment shows that the model is able to evaluate and compare different scenarios and can thus be a useful tool in planning processes.

  • 2.
    Ljunggren, Fredrik
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering. Trafikverket.
    Persson, Kristian
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering. Sweco.
    Peterson, Anders
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Schmidt, Christiane
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Maximum Robust Train Path for an Additional Train Inserted in a Railway Timetable Close to Operation2018Conference paper (Other academic)
    Abstract [en]

    We present an algorithm to insert a train path in an existing railway timetable close to operation, when we want to affect the existing (passenger) traffic as little as possible. Thus, we consider all other trains as fixed, and aim for a resulting train path that maximizes the bottleneck robustness. Our algorithm is based on a graph formulation of the problem and uses a variant of Dijkstra's algorithm.

    We present an extensive experimental evaluation of our algorithm for the Swedish railway stretch from Malmö to Hallsberg. Moreover, we analyze the size of our constructed graph.

  • 3.
    Solinen, Emma
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering. Trafikverket, Sundbyberg, Sweden.
    Nicholson, Gemma
    Birmingham Centre for Railway Research and Education, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
    Peterson, Anders
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    A microscopic evaluation of railway timetable robustness and critical points2017In: Journal of Rail Transport Planning & Management, ISSN 2210-9706, E-ISSN 2210-9714, Vol. 7, no 4, p. 207-223Article in journal (Refereed)
    Abstract [en]

    One method to increase the quality of railway traffic flow is to construct a more robust timetable in which trains are able both to recover from delays and the delays are prevented from propagating. Previous research results show that the indicator Robustness in Critical Points (RCP) can be used to increase timetable robustness. In this paper we present the use of a method for RCP optimization: how it can be assessed ex-post via microscopic simulation. From the evaluation we learn more about how increased RCP values influence a timetable's performance. The aim is to understand more about RCP increase at a localised level within a timetable in terms of effects to the pairs of trains that are part of the indicator. We present a case study where an initial timetable and a timetable with increased RCP values are evaluated. The ex-post evaluation includes the quantification of measures concerning train-borne delay and robustness of operations, as well as measures capturing the subsequent quality of service experienced by passengers to assess the broader effects of improved robustness. The result shows that it is necessary to use several key performance indicators (KPIs) to evaluate the effects of an RCP increase. The robustness increases at a localised level, but the results also indicate that there is a need to analyse the relationship between ex-post measures and RCP further, to improve the method used to increase RCP and thus its overall effect on timetable robustness.

  • 4.
    Solinen, Emma
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering. Trafikverket, Sundbyberg, Sweden.
    Nicholson, Gemma
    Birmingham Centre for Railway Research and Education, University of Birmingham, Unnited Kingdom.
    Peterson, Anders
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    A Microscopic Evaluation of Robustness in Critical Points2017In: 7th International Conference on RailwayOperations Modelling and Analysis (RailLille 2017) / [ed] N. Tomii, I.A. Hansen, J. Rodriguez, P. Pellegrini, S. Dauzère-Pérès, D. De Almeida, International Association of Railway Operations Research , 2017, p. 83-103, article id 1705Conference paper (Refereed)
    Abstract [en]

    One method to increase the quality of railway traffic flow is to construct a more robust timetable in which trains are able to both recover from delays and the delays are prevented from propagating. Previous research results show that the indicator Robustness in Critical Points (RCP) can be used to increase timetable robustness. In this paper we present the use of a method for RCP optimization, how can be implemented and assessed ex-post via microscopic simulation and subsequently evaluated. From the evaluation we learn more about how increased RCP values influence a timetable’s performance. The aim is to understand more about RCP increase at a localised level within a timetable in terms of effects to the pairs of trains that are part of the indicator. We present a case study where an initial timetable and a timetable with increased RCP values are evaluated. The ex-post evaluation includes the quantification of measures concerning train-borne delay and robustness of traffic flow, as well as measures capturing the subsequent quality of service experienced by passengers to assess the broader effects of improved robustness. The result shows that it is necessary to use several Key Performance Indicators (KPIs) to evaluate the effects of an RCP increase. The robustness will increase at a localised level, but the results also indicate that there is a need to analyse the relationship between ex-post measures and RCP further, to improve the method used to increase RCP and thus its overall effect on timetable robustness.

  • 5.
    Gestrelius, Sara
    et al.
    SICS RISE AB, Kista, Sweden.
    Aronsson, Martin
    SICS RISE AB, Kista, Sweden.
    Peterson, Anders
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    A MILP-based heuristic for a commercial train timetabling problem2017In: 20th EURO Working Group on Transportation Meeting, EWGT 2017, 4-6 September 2017, Budapest, Hungary, Elsevier, 2017, Vol. 27, p. 569-576Conference paper (Refereed)
    Abstract [en]

    Using mathematical methods to support the yearly timetable planning process has many advantages. Unfortunately, the train timetabling problem for large geographical areas and many trains is intractable for optimization models alone. In this paper, we therefore present a MILP-based heuristic that has been designed to generate good-enough timetables for large geographical areas and many trains. In the incremental fix and release heuristic (IFRH), trains are added to the timetable in batches. For each batch of trains, a reduced timetable problem is solved using a mathematical integer program and CPLEX. Based on the solution, the binary variables defining meeting locations and stops are fixed, and the next batch of trains is added to the timetable. If previously fixed variables make the problem infeasible, a recovery algorithm iteratively releases fixed variables to regain feasibility. The paper also introduces a simple improvement heuristic (IH) that uses the same idea of working with batches of trains. The heuristics are tested on a real case-study from Sweden consisting of both small problem instances (approximately 300 trains and 1400 possible interactions) and large problem instances (approximately 600 trains and 5500 possible interactions). IFRH returns a feasible timetable within 30 minutes for all problem instances, and after running IH the optimality gaps are less than 5%. Meanwhile, if CPLEX is used without the heuristic framework to solve the total optimization problem, a feasible timetable is not returned within 2 hours for the large problem instances.

  • 6.
    Lindberg, Therese
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering. VTI, Swedish National Road and Transport Research Institute, Linköping, Sweden; K2 - The Swedish Knowledge Center for Public Transport, Lund, Sweden.
    Peterson, Anders
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Tapani, Andreas
    VTI, Swedish National Road and Transport Research Institute, Linköping, Sweden; K2 - The Swedish Knowledge Center for Public Transport, Lund, Sweden.
    A Simulation Model of Local Public Transport Access at a Railway Station2017In: Proceedings of Raillille 2017 - 7th lnternational Conference on Railway Operations Modelling and Analysis / [ed] N. Tomii, I.A. Hansen, J. Rodriguez, P. Pellegrini, S. Dauzère-Pérès, D. De Almeida, 2017, p. 922-943Conference paper (Other academic)
    Abstract [en]

    A high quality railway service requires that all parts of the complete journey, from door to door, are well-functioning. This includes any transfers taking place, as well as last mile transportation to and from the railway station. Since the last mile often consists of local public transport, the access to this mode at stops and terminals and how well these are functioning are of great importance. A critical aspect is the capacity of the stop or the terminal in relation to the number of departures, where a higher capacity generally means an increase in size. At the same time it is desirable to limit the use of valuable land and keeping the facility as small as possible. The trade-off between capacity and size needs to be evaluated when designing stops and terminals. In this study we have developed a discrete event simulation model of a combined bus and tram stop, which is a part of a larger multi-modal station. The objective of the study is to evaluate the modelling approach for the situation at hand. Of special interest are the complexities due to the different driving patterns of buses and trams. The developed model is capable of evaluating design alternatives and is applied in a case study of a stop at Norrköping railway station in southern Sweden. The model was found to realistically capture the various events occurring at such a stop and the case study further showed that the model is a useful tool in design evaluation.

  • 7.
    Khoshniyat, Fahimeh
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Peterson, Anders
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Improving Train Service Reliability by Applying an Effective Timetable Robsutness Strategy2017In: Journal of Intelligent Transportation Systems / Taylor & Francis, ISSN 1547-2450, E-ISSN 1547-2442, Vol. 21, no 6, p. 525-543Article in journal (Refereed)
    Abstract [en]

    To avoid propagation of delays in dense railway timetables, it is important to ensure robustness. One strategy to improve robustness is to provide adequate amount of buffer times between trains. This study concerns how “scheduled minimum headways” should be determined in order to improve robustness in timetables. Scheduled minimum headways include technical minimum headway plus some buffer time. We propose a strategy to be implemented in timetables at the final stages of planning and prior to the operations.  The main contributions of this study are 1) to propose a strategy where the size of the scheduled minimum headways is dependent on trains' travel times instead of a fixed-sized time slot and it is called “travel time dependent scheduled minimum headways” or TTDSMH, 2) to evaluate the effects of the new strategy on heterogeneity, speed, and the number of trains in timetables, 3) to show that a simple strategy can improve robustness without imposing major changes in timetables. The strategy is implemented in an Mixed Integer Linear Programming framework for timetabling and tested for some problem instances from Sweden. Results show that TTDSMH can improve robustness. The proposed strategy can be applied in intelligent transportation tools for railway timetabling.

  • 8.
    Andersson, Emma
    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.
    Törnquist Krasemann, Johanna
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Improved Railway Timetable Robustness for Reduced Traffic Delays – a MILP approach2015In: 6th International Conference on Railway Operations Modelling and Analysis, Tokyo, Mars 23-26, 2015., 2015Conference paper (Refereed)
    Abstract [en]

    Maintaining high on-time performance and at the same time having high capacity utilization is a challenge for several railway traffic systems. The system becomes sensitive to disturbances and delays are easily propagating in the network. One way to handle this problem is to create more robust timetables; timetables that can absorb delays and prevent them from propagating. This paper presents an optimization approach to reduce the propagating of delays with a more efficient margin allocation in the timetable. A Mixed Integer Linear Programming (MILP) model is proposed in which the existing margin time is re-allocated to increase the robustness for an existing timetable. The model re-allocates both runtime margin time and headway margin time to increase the robustness at specific delay sensitive points in a timetable. We illustrate the model’s applicability for a real-world case where an initial, feasible timetable is modified to create new timetables with increased robustness. These new timetables are then evaluated and compared to the initial timetable. We evaluate how the MILP approach affects the initial timetable structure and its capability to handle disturbances by exposing the initial and the modified timetables to some minor initial disturbances of the range 1 up to 7 minutes. The results show that it is possible to reduce the delays by re-allocating margin time, for example, the total delay at end station decreases with 28 % in our real-world example.

  • 9.
    Khoshniyat, Fahimeh
    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.
    Robustness Improvements in a Train Timetable with Travel Time Dependent Minimum Headways2015Conference paper (Other academic)
    Abstract [en]

    In a railway network with dense traffic, trains’ scheduled arrival and departure times arehighly dependent on each other and even a small delay easily propagates to subsequenttrains using the same infrastructure resources. In the current paper a given timetable is comparedto a modified timetable, where the assigned minimum time slot in the traffic for aservice is linearly increasing with the service’s travel time. The underlying assumption isthat trains lose precision as they travel longer and catching a fixed-size time slot is easier atthe beginning of the journey. Real world observations confirm this assumption as well. Theaim of this study is to verify the improvement in the robustness of those timetables that aremodified with respect to the idea of travel time dependent reserved time slots for the arrivaltimes of trains and to compare the results with the initial timetables. Numerical experimentsare conducted on a selected double track segment of the Swedish Southern mainline. Fourtimetable case studies are considered for the experiments: off-peak hours and peak hoursin 2011 and 2014, respectively. Each timetable is tested for various disturbance scenarios.Several performance measures are used to evaluate delay propagation in the timetables, includingdeviations from the initial timetable, total delays, total number of delayed trains atdestinations, number of punctual trains with 5 minutes arrival delay tolerance at destinationsand number of violations in trains’ overtaking orders. Results show that the modifiedtimetables outperform the initial ones for small disturbances.

  • 10.
    Kecman, Pavle
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Corman, Francesco
    Delft University of Technology, The Netherlands.
    Peterson, Anders
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Joborn, Martin
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Stochastic prediction of train delays in real-time using Bayesian networks2015In: Conference on Advanced Systems in Public Transport: CASPT2015, ETH Zurich, 2015Conference paper (Refereed)
    Abstract [en]

    In this paper we present a stochastic model for predicting the propagation of train delays based on Bayesian networks. This method can eciently represent and compute the complex stochastic inference between random variables. Moreover, it allows updating the probability distributions and reducing the uncertainty of future train delays in real time under the assumption that more information continuously becomes available from the monitoring system. The dynamics of a train delay over time and space is presented as a stochastic process that describes the evolution of the time-dependent random variable. This approach is further extended by modelling the interdependence between trains that share the same infrastructure of have a scheduled passenger transfer. The model is applied on a set of historical trac realisation data from the part of a busy corridor in Sweden.We present the initial results and analyse the accuracy of predictions as well as the evolution of probability distributions of event delays over time. The presented method is important for making better predictions for train trac, that are not only based on static, oine collected data, but are able to positively include the dynamic characteristics of the continuously changing delays.

  • 11.
    Johansson, Fredrik
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology. Swedish National Rd and Transport Research Institute VTI, SE-58195 Linkoping, Sweden.
    Peterson, Anders
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Tapani, Andreas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology. Swedish National Rd and Transport Research Institute VTI, SE-58195 Linkoping, Sweden.
    Waiting pedestrians in the social force model2015In: Physica A: Statistical Mechanics and its Applications, ISSN 0378-4371, E-ISSN 1873-2119, Vol. 419, p. 95-107Article in journal (Refereed)
    Abstract [en]

    Microscopic simulation of pedestrian traffic is an important and increasingly popular method to evaluate the performance of existing or proposed infrastructure. The social force model is a common model in simulations, describing the dynamics of pedestrian crowds given the goals of the simulated pedestrians encoded as their preferred velocities. The main focus of the literature has so far been how to choose the preferred velocities to produce realistic dynamic route choices for pedestrians moving through congested infrastructure. However, limited attention has been given the problem of choosing the preferred velocity to produce other behaviors, such as waiting, commonly occurring at, e.g., public transport interchange stations. We hypothesize that: (1) the inclusion of waiting pedestrians in a simulated scenario will significantly affect the level of service for passing pedestrians, and (2) the details of the waiting model affect the predicted level of service, that is, it is important to choose an appropriate model of waiting. We show that the treatment of waiting pedestrians have a significant impact on simulations of pedestrian traffic. We do this by introducing a series of extensions to the social force model to produce waiting behavior, and provide predictions of the model extensions that highlight their differences. We also present a sensitivity analysis and provide sufficient criteria for stability. (C) 2014 Elsevier B.V. All rights reserved.

  • 12.
    Johansson, Fredrik
    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.
    Tapani, Andreas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Local performance measures of pedestrian traffic2014In: Public Transport, ISSN 1866-749X, E-ISSN 1613-7159, Vol. 6, no 1-2, p. 159-183Article in journal (Refereed)
    Abstract [en]

    Efficient interchange stations, where travelers are changing lines and/or travel modes, are essential for the functionality of the whole public transport system. By studying pedestrian movements, the level of service and effectiveness imposed by the design of the interchange station can be evaluated. We address the problem by microsimulation, where a social force model is used for the phenomenological description of pedestrian interactions. The contribution of this paper is the proposal of measures describing the density, delay, acceleration and discomfort for pedestrian flows. Simulation experiments are performed for the movements in two canonical pedestrian areas, a corridor and a corridor intersection. Clearly, each of the four measures gives a description for how pedestrians impede each other, and hence for the efficiency at the facility. There is, however, different information provided by each measure, and we conclude that they all are well-motivated for quantifying the level of service in a pedestrian flow. We also illustrate the outcome for a railway platform, with two trains arriving in parallel.

  • 13.
    Häll, Carl Henrik
    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.
    Improving paratransit scheduling using ruin and recreate methods2013In: Transportation planning and technology (Print), ISSN 0308-1060, E-ISSN 1029-0354, Vol. 36, no 4, p. 377-393Article in journal (Refereed)
    Abstract [en]

    In this paper we study the effects of using ruin and recreate methods in a replanning phase of a dynamic dial-a-ride problem. Several such methods are proposed, and a modeling system is used to evaluate how they improve the quality of the solutions. We show that simple changes to existing planning methods can increase the efficiency of the service. Two cases, with different forms of costs inflicted on the vehicles, are evaluated and significant improvements are found in both cases. The best results of our study are found with ruin methods based on removal of sequences of requests.

  • 14.
    Andersson, Emma
    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.
    Törnquist Krasemann, Johanna
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Introducing a New Quantitative Measure of Railway Timetable Robustness Based on Critical Points2013In: 5th International Seminar on Railway Operations Modelling and Analysis - RailCopenhagen 2013, 2013Conference paper (Refereed)
    Abstract [en]

    The growing demand for railway capacity has led to high capacity consumption at times and a delay-sensitive network with insufficient robustness. The fundamental challenge is therefore to decide how to increase the robustness. To do so there is a need for accurate measures that return whether the timetable is robust or not and indicate where improvements should be made. Previously presented measures are useful when comparing different timetable candidates with respect to robustness, but less useful to decide where and how robustness should be inserted. In this paper, we focus on points where trains enter a line, or where trains are being overtaken, since we have observed that these points are critical for the robustness. The concept of critical points can be used in the practical timetabling process to identify weaknesses in a timetable and to provide suggestions for improvements. In order to quantitatively assess how crucial a critical point may be, we have defined the measure RCP (Robustness in Critical Points). A high RCP value is preferred, and it reflects a situation at which train dispatchers will have higher prospects of handling a conflict effectively. The number of critical points, the location pattern and the RCP values constitute an absolute value for the robustness of a certain train slot, as well as of a complete timetable. The concept of critical points and RCP can be seen as a contribution to the already defined robustness measures which combined can be used as guidelines for timetable constructors.

  • 15.
    Andersson, Emma V.
    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.
    Törnquist Krasemann, Johanna
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology. Blekinge Institute of Technology, Department of Computer Science and Engineering, Karlskrona, Sweden .
    Quantifying railway timetable robustness in critical points2013In: Journal of Rail Transport Planning & Management, ISSN 2210-9706, E-ISSN 2210-9714, Vol. 3, no 3, p. 95-110Article in journal (Refereed)
    Abstract [en]

    Several European railway traffic networks experience high capacity consumption during large parts of the day resulting in delay-sensitive traffic system with insufficient robustness. One fundamental challenge is therefore to assess the robustness and find strategies to decrease the sensitivity to disruptions. Accurate robustness measures are needed to determine if a timetable is sufficiently robust and suggest where improvements should be made.

    Existing robustness measures are useful when comparing different timetables with respect to robustness. They are, however, not as useful for suggesting precisely where and how robustness should be increased. In this paper, we propose a new robustness measure that incorporates the concept of critical points. This concept can be used in the practical timetabling process to find weaknesses in a timetable and to provide suggestions for improvements. In order to quantitatively assess how crucial a critical point may be, we have defined the measure Robustness in Critical Points (RCP). In this paper, we present results from an experimental study where a benchmark of several measures as well as RCP has been done. The results demonstrate the relevance of the concept of critical points and RCP, and how it contributes to the set of already defined robustness measures.

  • 16.
    Fowler, Scott
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Hameseder, Katrin
    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.
    An Empirical Evaluation of Web System Access for Smartphone Clients2012In: Journal of Networks, ISSN 1796-2056, E-ISSN 1796-2056, Vol. 7, no 11, p. 1700-1713Article in journal (Refereed)
    Abstract [en]

    As smartphone clients are restricted in computational power and bandwidth, it is important to minimise the overhead of transmitted messages.  This paper identifies and studies methods that reduce the amount of data being transferred via wireless links between a web service client and a web service. Measurements were performed in a real environment based on a web service prototype providing public transport information for the city of Hamburg in Germany, using actual wireless links with a mobile smartphone device.  REST based web services using the data exchange formats JSON, XML and Fast Infoset were evaluated against the existing SOAP based web service.

  • 17.
    Johansson, Fredrik
    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.
    Tapani, Andreas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Performance evaluation of railway platform design using microscopic simulation2012Conference paper (Other academic)
    Abstract [en]

    Efficient interchange stations, where travelers are changing lines and/or travel modes, are essential for the functionality of the whole public transport system. By studying pedestrian movements, the level of service and effectiveness imposed by the design of the interchange station can be evaluated.

    We address the problem by microsimulation, where a social force model is used for the phenomenological description of pedestrian interactions. The contribution of this paper is the proposal of measures describing the density, delay, acceleration and discomfort for pedestrian flows.

    Simulation experiments are performed for the movements in two canonical pedestrian areas, a corridor and a corridor intersection. Clearly, each of the four measures gives a description for how pedestrians impede each other, and hence for the efficiency at the facility. There is, however, different information provided by each measure, and we conclude that they all are well-motivated for quantifying the level of service in a pedestrian flow. We also illustrate the outcome for a railway platform, with two trains arriving in parallel.

  • 18.
    Peterson, Anders
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Towards a robust traffic timetable for the Swedish Southern Mainline2012In: Computers in Railways XIII: Computer System Design and Operation in the Railway and Other Transit Systems / [ed] C.A. Brebbia, N. Tomil, J.M. Mera, B. Ning & P. Tzieropoulos, Ashurst: WIT Press, 2012, p. 473-484Conference paper (Other academic)
    Abstract [en]

    We identify the on-time performance as a key to evaluate a railway timetable’s robustness to disturbances and evaluate the on-time performance for two single services on the Swedish Southern Mainline for the autumn period 2011. We analyse the punctuality by studying how the performance develops en route. Typically the time spent in the stations is underestimated, which partly is compensated for by time margins along the line, giving rise to a sawtooth formed delay muster with an increasing trend. The standard deviation in the delay reports seems to be a good indicator for the precision in the traffic. In this material it is almost linearly increasing with a good minute per hour scheduled running time. Two attempts are made to change the timetable for a better performance. By using socio-economic values a customer-oriented description of the current timetable is calculated as a trade-off between high punctuality and short travel time. This timetable does not affect any other traffic. Minor effects to other traffic would be the result if the existing margins are re-distributed to better match the demand en route in some sense. As long as no more time supplement is added, we will, however, not improve on the punctuality to the final destination. For future research is left, how the decrease in precision can be accounted for already in the timetable construction.

  • 19.
    Hameseder, Katrin
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Fowler, Scott
    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.
    Performance Analysis of Ubiquitous Web Systems for SmartPhones2011In: Proceedings of the 2011International Symposium onPerformance Evaluation of Computerand Telecommunication Systems / [ed] Mohammad S., Obaidat José L., Sevillano, Pere Vilá, Isaac Woungang, Raffaele Bolla, Daniel Cascado, IEEE , 2011, p. 84-89Conference paper (Refereed)
    Abstract [en]

    As smartphone clients are restricted in computational power and bandwidth it is important to minimise the overhead of transmitted messages and since it results in processing time when implementing a web service. This paper identifies and studies methods that reduce the amount of data being transferred via wireless links between a Web service client and a Web service. The goal is to improve the end-to-end service execution time by reducing the bottleneck presented by the limited bandwidth in an ubiquitous environment. Measurements are performed in a real environment based on a web service prototype providing public transport information for the city of Hamburg in Germany, using actual wireless links with a mobile smartphone device. The existing SOAP based web service is evaluated against a REST based web service using the data exchange formats JSON, XML and Fast Infoset.

  • 20.
    Andersson, Emma
    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.
    Törnquist Krasemann, Johanna
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Robustness in Swedish Railway Traffic Timetables2011In: Railrome 2011: Book of Abstracts 4th International Seminar on Railway Operations Modelling and Analysis / [ed] S. Ricci, I.A. Hansen, G. Longo, D. Pacciarelli, J. Rodriguez, E. Wendler, 2011Conference paper (Other academic)
    Abstract [en]

    A tendency seen for quite some time in the Swedish railway network is a growing demand for capacity which no longer can be accommodated. This causes congestion and delays, and the relationships between the trains and how they affect eachother are significantly harder to overview and analyse. Railway traffic timetables normally contain margins to make them robust, and enable trains to recover from certain delays. How effective these margins are, depends on their size and location as well as the frequency and magnitude of the disturbances that occur. Hence, it is important to include marigns so, that they can be used operationally to recover from a variety of disturbances and not restricted to a specific part of the line and/or the timetable. In a case study we compare the performance of a selection of passenger train services to the different prerequisites given by the timetable (e.g. available margins and their location, critical train dependencies). The study focuses on the Swedish Southern mainline between Stockholm and Malmö on which a wide variety of train services operate, e.g. freight trains, local and regional commuter train services as well as long-distance trains with different speed profiles. The analysis shows a clear mismatch between where margins are placed and where delays occur. We also believe that the most widely used performance measure, which is related to the delay when arriving at the final destination, might give rise to an unnecessarily high delay rate at intermediate stations.

  • 21.
    Larsson, Torbjörn
    et al.
    Linköping University, Department of Mathematics, Optimization . Linköping University, The Institute of Technology.
    Lundgren, Jan
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology, Communications and Transport Systems.
    Peterson, Anders
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology, Communications and Transport Systems.
    Allocation of Link Flow Detectors for Origin-Destination Matrix Estimation-A Comparative Study2010In: COMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, ISSN 1093-9687, Vol. 25, no 2, p. 116-131Article in journal (Refereed)
    Abstract [en]

    Origin-destination (OD) matrices are essential for various analyses in the field of traffic planning, and they are often estimated from link flow observations. We compare methods for allocating link flow detectors to a traffic network with respect to the quality of the estimated OD-matrix. First, an overview of allocation methods proposed in the literature is presented. Second, we construct a controlled experimental environment where any allocation method can be evaluated, and compared to others, in terms of the quality of the estimated OD-matrix. Third, this environment is used to evaluate and compare three fundamental allocation methods. Studies are made on the Sioux Falls network and on a network modeling the city of Linkoping. Our conclusion is, that the most commonly studied approach for detector allocation, maximizing the coverage of OD-pairs, seems to be unfavorable for the quality of the estimated OD-matrix.

  • 22.
    Häll, Carl Henrik
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Lundgren, Jan T.
    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.
    Improving the efficiency of swedish paratransit: an application of the dial-a-ride problem2009Conference paper (Other academic)
  • 23.
    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.
    A Heuristic for the Bilevel Origin–Destination Matrix Estimation Problem2008In: Transportation Research Part B: Methodological, ISSN 0191-2615, E-ISSN 1879-2367, Vol. 42, no 4, p. 339-354Article in journal (Refereed)
    Abstract [en]

    In this paper we consider the estimation of an origin–destination (OD) matrix, given a target OD-matrix and traffic counts on a subset of the links in the network. We use a general nonlinear bilevel minimization formulation of the problem, where the lower level problem is to assign a given OD-matrix onto the network according to the user equilibrium principle. After reformulating the problem to a single level problem, the objective function includes implicitly given link flow variables, corresponding to the given OD-matrix. We propose a descent heuristic to solve the problem, which is an adaptation of the wellknown projected gradient method. In order to compute a search direction we have to approximate the Jacobian matrix representing the derivatives of the link flows with respect to a change in the OD-flows, and we propose to do this by solving a set of quadratic programs with linear constraints only. If the objective function is differentiable at the current point, the Jacobian is exact and we obtain a gradient. Numerical experiments are presented which indicate that the solution approach can be applied in practice to medium to large size networks.

  • 24.
    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)
  • 25.
    Peterson, Anders
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    The Origin-Destination Matrix Estimation Problem: Analysis and Computations2007Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    For most kind of analyses in the field of traffic planning, there is a need for origin--destination (OD) matrices, which specify the travel demands between the origin and destination nodes in the network. This thesis concerns the OD-matrix estimation problem, that is, the calculation of OD-matrices using observed link flows. Both time-independent and time-dependent models are considered, and we also study the placement of link flow detectors.

    Many methods have been suggested for OD-matrix estimation in time-independent models, which describe an average traffic situation. We assume a user equilibrium to hold for the link flows in the network and recognize a bilevel structure of the estimation problem. A descent heuristic is proposed, in which special attention is given to the issue of calculating the change of a link flow with respect to a change of the travel demand in a certain pair of origin and destination nodes.

    When a time-dimension is considered, the estimation problem becomes more complex. Besides the problem of distributing the travel demand onto routes, the flow propagation in time and space must also be handled. The time-dependent OD-matrix estimation problem is the subject for two studies. The first is a case study, where the conventional estimation technique is improved through introducing pre-adjustment schemes, which exploit the structure of the information contained in the OD-matrix and the link flow observations. In the second study, an algorithm for time-independent estimation is extended to the time-dependent case and tested for a network from Stockholm, Sweden.

    Finally, we study the underlying problem of finding those links where traffic flow observations are to be performed, in order to ensure the best possible quality of the estimated OD-matrix. There are different ways of quantifying a common goal to cover as much traffic as possible, and we create an experimental framework in which they can be evaluated. Presupposing that consistent flow observations from all the links in the network yields the best estimate of the OD-matrix, the lack of observations from some links results in a relaxation of the estimation problem, and a poorer estimate. We formulate the problem to place link flow detectors as to achieve the least relaxation with a limited number of detectors.

    List of papers
    1. A Heuristic for the Bilevel Origin–Destination Matrix Estimation Problem
    Open this publication in new window or tab >>A Heuristic for the Bilevel Origin–Destination Matrix Estimation Problem
    2008 (English)In: Transportation Research Part B: Methodological, ISSN 0191-2615, E-ISSN 1879-2367, Vol. 42, no 4, p. 339-354Article in journal (Refereed) Published
    Abstract [en]

    In this paper we consider the estimation of an origin–destination (OD) matrix, given a target OD-matrix and traffic counts on a subset of the links in the network. We use a general nonlinear bilevel minimization formulation of the problem, where the lower level problem is to assign a given OD-matrix onto the network according to the user equilibrium principle. After reformulating the problem to a single level problem, the objective function includes implicitly given link flow variables, corresponding to the given OD-matrix. We propose a descent heuristic to solve the problem, which is an adaptation of the wellknown projected gradient method. In order to compute a search direction we have to approximate the Jacobian matrix representing the derivatives of the link flows with respect to a change in the OD-flows, and we propose to do this by solving a set of quadratic programs with linear constraints only. If the objective function is differentiable at the current point, the Jacobian is exact and we obtain a gradient. Numerical experiments are presented which indicate that the solution approach can be applied in practice to medium to large size networks.

    Place, publisher, year, edition, pages
    Institutionen för teknik och naturvetenskap, 2008
    Keywords
    Origin-Destination matrix; Sensitivity analysis; User-equilibrium
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-11461 (URN)10.1016/j.trb.2007.09.005 (DOI)
    Note
    Original publication: Jan T Lundgren and Anders Peterson, A Heuristic for the Bilevel Origin–Destination Matrix Estimation Problem, 2008, Transportation Research Part B: Methodological, (42), 4, 339-354. http://dx.doi.org/10.1016/j.trb.2007.09.005. Copyright: Elsevier B.V., http://www.elsevier.com/Available from: 2008-04-03 Created: 2008-04-03 Last updated: 2018-08-23
    2. Methods for Pre-Adjusting Time-Dependent Origin–Destination Matrices: an Application to Gothenburg
    Open this publication in new window or tab >>Methods for Pre-Adjusting Time-Dependent Origin–Destination Matrices: an Application to Gothenburg
    2003 (English)In: Proceedings of the 10th World Congress and Exhibition on Intelligent Transport Systems and Services, Madrid, Spain, November 16–20, 2003, no 2436Conference paper, Published paper (Refereed)
    Abstract [en]

    We present a number of schemes for adjusting time-dependent travel demand information with respect to link flow observations. The aim is to utilize the structure of the given OD-matrix, which is compounded from different sources, for making simple overall adjustments. These pre-adjustments are then followed up with a complete OD-estimation procedure, such as that in Contram. Numerical results from the city of Gothenburg are presented.

    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-14467 (URN)
    Conference
    10th World Congress and Exhibition on Intelligent Transport Systems and Services, Madrid, Spain, November 16–20
    Available from: 2007-06-04 Created: 2007-06-04 Last updated: 2018-08-23
    3. A Heuristic for the Estimation of Time-Dependent Origin Origin–Destination Matrices from Traffic Counts
    Open this publication in new window or tab >>A Heuristic for the Estimation of Time-Dependent Origin Origin–Destination Matrices from Traffic Counts
    2007 (English)In: 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, Published paper (Refereed)
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-14468 (URN)
    Conference
    The 10th Jubilee Meeting of the EURO Working Group on Transportation, Poznan, Poland, September 13–16, 2005
    Available from: 2007-06-04 Created: 2007-06-04 Last updated: 2018-08-23
    4. Allocation of Link Flow Detectors for Origin-Destination Matrix Estimation-A Comparative Study
    Open this publication in new window or tab >>Allocation of Link Flow Detectors for Origin-Destination Matrix Estimation-A Comparative Study
    2010 (English)In: COMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, ISSN 1093-9687, Vol. 25, no 2, p. 116-131Article in journal (Refereed) Published
    Abstract [en]

    Origin-destination (OD) matrices are essential for various analyses in the field of traffic planning, and they are often estimated from link flow observations. We compare methods for allocating link flow detectors to a traffic network with respect to the quality of the estimated OD-matrix. First, an overview of allocation methods proposed in the literature is presented. Second, we construct a controlled experimental environment where any allocation method can be evaluated, and compared to others, in terms of the quality of the estimated OD-matrix. Third, this environment is used to evaluate and compare three fundamental allocation methods. Studies are made on the Sioux Falls network and on a network modeling the city of Linkoping. Our conclusion is, that the most commonly studied approach for detector allocation, maximizing the coverage of OD-pairs, seems to be unfavorable for the quality of the estimated OD-matrix.

    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-53695 (URN)10.1111/j.1467-8667.2009.00625.x (DOI)
    Available from: 2010-02-01 Created: 2010-02-01 Last updated: 2018-08-23
    5. A Novel Model for Placement of Detectors for Origin–Destination Matrix Estimation
    Open this publication in new window or tab >>A Novel Model for Placement of Detectors for Origin–Destination Matrix Estimation
    Manuscript (Other academic)
    Identifiers
    urn:nbn:se:liu:diva-14470 (URN)
    Available from: 2007-06-04 Created: 2007-06-04 Last updated: 2010-01-13
  • 26.
    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)
  • 27.
    Lundgren, Jan T.
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems.
    Peterson, Anders
    Linköping University, Department of Science and Technology, Communications and Transport Systems.
    Tengroth, Stellan
    Vägverket Region Väst, Swedish National Road Administration.
    Methods for Pre-Adjusting Time-Dependent Origin–Destination Matrices: an Application to Gothenburg2003In: Proceedings of the 10th World Congress and Exhibition on Intelligent Transport Systems and Services, Madrid, Spain, November 16–20, 2003, no 2436Conference paper (Refereed)
    Abstract [en]

    We present a number of schemes for adjusting time-dependent travel demand information with respect to link flow observations. The aim is to utilize the structure of the given OD-matrix, which is compounded from different sources, for making simple overall adjustments. These pre-adjustments are then followed up with a complete OD-estimation procedure, such as that in Contram. Numerical results from the city of Gothenburg are presented.

  • 28.
    Peterson, Anders
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Origin-destination matrix estimation from traffic counts2003Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    For most kind of analyses in the field of traffic modeling, there is a need for origin-destination (OD) matrices, which specify the travel demands between the origin and destination nodes in the network. The process of obtaining OD-matrices is long, complicated and expensive. The counting of traffic, which provides link flow observations, therefore is an opportune possibility for easily up-dating the information on the travel demand. This thesis concerns the estimation of OD-matrices from traffic counts. 

    We will consider the problem to estimate OD-matrices for both time-indepenent and time-dependent models. Many models have been suggested for the time-independent case, where the quantities represent and average situation. If a user equilibrium is assumed for the link flows in the network, a bilevel problem structure is recognized, where the link flows are implicitly expressed as a traffic assignment of the present OD-matrix. A descent heuristic, which is an adaptation of the well-known projected gradient method, is proposed. Special attention is given to the problem of approximating the Jacobian matrix, which expresses the change of a certain link flow with respect to a unit change of the travel demand in a certain pair of origin and destination.

    When a time dimension is introduced, the estimation problem becomes more complex. Besides the problem of distributing the travel demand onto different routes, the flow propagation with respect to time must be handled. A general time-dependent extension of the estimation problem is given and the complications with dynamic traffic assignment are discussed. In a case study, the conventional solution technique is improved by introducing pre-adjustment schemes, which the structure of the information provided by the OD-matrix and the link flow observations.

    List of papers
    1. Traffic Demand Modeling and Origin-Destination Matrix Estimation
    Open this publication in new window or tab >>Traffic Demand Modeling and Origin-Destination Matrix Estimation
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    An origin-destination (OD) matrix describes the travel demand between all pairs of origins and destinations in a traffic network. OD-matrices are essential input for most types traffic models, both for long-term planning, where the actions are meant to be permanent, and for short-term planning, where the operational situation is managed. This paper is a literature overview of models and methods for obtaining reliable OD-matrices.

    We present the Four-stage model which is commonly used for sequentially computing the number of trips starting and terminating at the centroid nodes, the distribution to travel demand between origins and destinations, the split onto different travel modes and the choice-based assignment of routes and links in the network. Further, we identify the information contained in traffic counts as an important source for adjusting the computed OD-matrix. The generic OD-matrix estimation problem from link flow observations is formulated and we discuss different solution techniques and how they relate to the assumptions used for the assignment of travel demand to routes and links.

    Time-dependence is a fundamental difference between the model types. A time-independent (static) model describes a steady state, which represents and average situation. If the interaction between sequential time periods is to be analyzed, however, a dynamic model is required. The time dimension is a complicating factor, since not only the route choice, but also the flow propagation must be taken care of in the model. Especially those models where the OD-matrix is to be estimated in real-time, must be simplified as to the computational effort.

    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-102432 (URN)
    Available from: 2013-12-10 Created: 2013-12-10 Last updated: 2018-08-23
    2. A Heuristic for the Bilevel Origin–Destination Matrix Estimation Problem
    Open this publication in new window or tab >>A Heuristic for the Bilevel Origin–Destination Matrix Estimation Problem
    2008 (English)In: Transportation Research Part B: Methodological, ISSN 0191-2615, E-ISSN 1879-2367, Vol. 42, no 4, p. 339-354Article in journal (Refereed) Published
    Abstract [en]

    In this paper we consider the estimation of an origin–destination (OD) matrix, given a target OD-matrix and traffic counts on a subset of the links in the network. We use a general nonlinear bilevel minimization formulation of the problem, where the lower level problem is to assign a given OD-matrix onto the network according to the user equilibrium principle. After reformulating the problem to a single level problem, the objective function includes implicitly given link flow variables, corresponding to the given OD-matrix. We propose a descent heuristic to solve the problem, which is an adaptation of the wellknown projected gradient method. In order to compute a search direction we have to approximate the Jacobian matrix representing the derivatives of the link flows with respect to a change in the OD-flows, and we propose to do this by solving a set of quadratic programs with linear constraints only. If the objective function is differentiable at the current point, the Jacobian is exact and we obtain a gradient. Numerical experiments are presented which indicate that the solution approach can be applied in practice to medium to large size networks.

    Place, publisher, year, edition, pages
    Institutionen för teknik och naturvetenskap, 2008
    Keywords
    Origin-Destination matrix; Sensitivity analysis; User-equilibrium
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-11461 (URN)10.1016/j.trb.2007.09.005 (DOI)
    Note
    Original publication: Jan T Lundgren and Anders Peterson, A Heuristic for the Bilevel Origin–Destination Matrix Estimation Problem, 2008, Transportation Research Part B: Methodological, (42), 4, 339-354. http://dx.doi.org/10.1016/j.trb.2007.09.005. Copyright: Elsevier B.V., http://www.elsevier.com/Available from: 2008-04-03 Created: 2008-04-03 Last updated: 2018-08-23
    3. Methods for Pre-Adjusting Time-Dependent Origin–Destination Matrices: an Application to Gothenburg
    Open this publication in new window or tab >>Methods for Pre-Adjusting Time-Dependent Origin–Destination Matrices: an Application to Gothenburg
    2003 (English)In: Proceedings of the 10th World Congress and Exhibition on Intelligent Transport Systems and Services, Madrid, Spain, November 16–20, 2003, no 2436Conference paper, Published paper (Refereed)
    Abstract [en]

    We present a number of schemes for adjusting time-dependent travel demand information with respect to link flow observations. The aim is to utilize the structure of the given OD-matrix, which is compounded from different sources, for making simple overall adjustments. These pre-adjustments are then followed up with a complete OD-estimation procedure, such as that in Contram. Numerical results from the city of Gothenburg are presented.

    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-14467 (URN)
    Conference
    10th World Congress and Exhibition on Intelligent Transport Systems and Services, Madrid, Spain, November 16–20
    Available from: 2007-06-04 Created: 2007-06-04 Last updated: 2018-08-23
  • 29.
    Peterson, Anders
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Traffic Demand Modeling and Origin-Destination Matrix EstimationManuscript (preprint) (Other academic)
    Abstract [en]

    An origin-destination (OD) matrix describes the travel demand between all pairs of origins and destinations in a traffic network. OD-matrices are essential input for most types traffic models, both for long-term planning, where the actions are meant to be permanent, and for short-term planning, where the operational situation is managed. This paper is a literature overview of models and methods for obtaining reliable OD-matrices.

    We present the Four-stage model which is commonly used for sequentially computing the number of trips starting and terminating at the centroid nodes, the distribution to travel demand between origins and destinations, the split onto different travel modes and the choice-based assignment of routes and links in the network. Further, we identify the information contained in traffic counts as an important source for adjusting the computed OD-matrix. The generic OD-matrix estimation problem from link flow observations is formulated and we discuss different solution techniques and how they relate to the assumptions used for the assignment of travel demand to routes and links.

    Time-dependence is a fundamental difference between the model types. A time-independent (static) model describes a steady state, which represents and average situation. If the interaction between sequential time periods is to be analyzed, however, a dynamic model is required. The time dimension is a complicating factor, since not only the route choice, but also the flow propagation must be taken care of in the model. Especially those models where the OD-matrix is to be estimated in real-time, must be simplified as to the computational effort.

1 - 29 of 29
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