Previous Research Projects
Below is a list of research projects that are completed.
- Estimation of transport demand based on mobile phone signaling data (MODE)
- Robust timetables for railway traffic
- Development of planning methods for community-financed travel
- Taxation shift in road traffic - system design and implementation strategy
- Models and methods for simulation of surrounding vehicles in driving simulators
- Rural Road Traffic Simulation
- Global optimization of congestion pricing schemes
- Link flow detector placement
- DORIS - Design of optimal road charging systems
- Current use and future development of model for multimodal traffic systems
- Realtime-GIS for transportation
- Models and Methods for Estimation of Origin–Destination Matrices
- Estimation of volume delay functions for urban environments based on an analytical intersection model
- Toward the development of techniques for designing equitable, efficient & acceptable urban transport systems
- Development and Analysis of integrated Public Transportation
Estimation of transport demand based on mobile phone signaling data (MODE)
Participants: Clas Rydergren, Nils Breyer (TS), David Gundlegård (MT) and Di Yuan (MT)
The project aims at estimation of travel demand in cities and metropolitan areas, via utilization of signaling data in cellular communications networks. The key applications of using cellular network data range from dynamically managing road traffic to long-term infrastructure planning. The specific objectives are to enhance the capability of short-term prediction of road traffic and accumulate knowledge on using mobility estimation as an enabler in addressing future challenges in sustainable development of the transport sector. The project contributes to a more efficient and sustainable transportation system, by means of developing better forecast models for road traffic and dynamic traffic management. Enhanced capability of estimating travel demand also contributes to higher comfort for travel, as the transport management system then has the ability of self-adaptation for existing and forthcoming travel needs. A specific result of the project is a prototype that guarantees privacy and enables dynamic estimation of travel demand and mobility.
This project is part of Transport Analytics Lab.
Partners: Ericsson, SICS, Trafikverket, City of Stockholm, and Sweco.
Financed by: Vinnova
Contact: Clas Rydergren
Robust timetables for railway traffic
Participants: Emma Andersson, Anders Peterson and Johanna Törnquist Krasemann.
During 2008, the railway passenger traffic in Sweden reached its all-time high which is double the volume of 1990. It is a very positive trend but the growing demand for railway transportation has also resulted in a capacity insufficiency and a high sensitivity to traffic disturbances. Even a small disturbance of one single train can have a significant impact on other trains since the capacity is fully utilized with very little buffer. One challenge is therefore to design robust timetables which contain margins on strategic places known to the traffic managers and thus increasing the possibilities for the network to absorb certain disturbances. The Swedish Transport Administration and SJ have also stated the need for methods which can compute robust timetables and create an improved feed-back loop between the timetabling phase and the real-time traffic management.
Our project aims to develop and evaluate such a method based on optimization techniques in cooperation with our partners, with the purpose to increase the reliability and punctuality of the Swedish railway traffic. When the number of operators and available services increase in line with the Swedish deregulation, it becomes even more important that individual operators and their services together form a functioning transport system so that passengers and freight transport buyers continue to see the railway system as an attractive means of transportation.
Partners: The Swedish Transport Administration and SJ AB.
Financed by: Swedish Transport Administration, VINNOVA and SJ AB
Contact: Emma Andersson
Project homepage: http://staffwww.itn.liu.se/~johto/RTJ.htm
Development of planning methods for community-financed travel
The project aims to develop planning methods for higher efficiency of community-financed travel. The project has two parts. The first part is about development of a planning support system to be used to evaluate the effects of different types of coordination between different forms of public transport; fixed route services, school buses, special transport services and demand responsive public transport. The second part is about evaluation and development of algorithms to use for planning of demand responsive transport. The project will result in recommendations on how to coordinate different forms of public transport, and give estimations on the financial savings that new planning algorithms can give. Potential customers are operators of public transport, local authorities and developers of planning systems for public transport. The results are believed to give developers of planning systems for community-financed travel better possibilities to further develop and improve their products. For more detailed information in Swedish, see the project page on the project web page.
Partners: Norrköpings Municipality, Malmator, Planit Sweden AB, Västtrafik and Östgötatrafiken.
Financed by: Swedish Rail Administration, Swedish Road Administration and VINNOVA (Swedish Governmental Agency for Innovation Systems).
Contact: Carl-Henrik Häll
Taxation shift in road traffic - system design and implementation strategy
Participants: Clas Rydergren and Joakim Ekström
As environmental requirements tighten the need of measures for reducing emissions from road traffic increases. A modern fleet with energy-efficient vehicles is one of the most obvious measures. This is not without problems: In some countries (e.g. Norway, Denmark, and the Netherlands) is the purchase tax (excise tax) an important national tax base, and in most countries the fuel tax is a significant revenue for the government. This measure therefore results in significantly lower tax revenues. As a counter measure, variations to the purchase tax system can be applied. In France, a Bonus Malus system has been applied as an environmental tax on purchases, with the intention to make the effect on the tax more neutral. The project comprises two parts: (1) Distance-based toll systems for all vehicles, and (2) Implementation of taxation shifts. In the first part, a distance-based toll system for both cars and heavy goods vehicles. By developing existing models and methods for designing charging zones, the effects of these systems can be evaluated and compared with existing, traditional, types of congestion charge systems. For example, the same type of social-economic dimensions of calculation previously used for the Stockholm system can be used on this type of system. This allows for fair comparisons. Output from the method is proposed tolling zones, i.e., zone boundaries and the charge per kilometer within the zone. In the second part, implementation of taxation shifts, we study the difficulties that arise related to the taxation shift that results from the charging scheme implementation.
Partners: Marie Karlsson and Jonas Sundberg, Sweco.
Financed by: Swedish Transport Administration
Contact: Clas Rydergren
Models and methods for simulation of surrounding vehicles in driving simulators
Participants: Johan Janson Olstam and Jan Lundgren
Driving simulators are used to conduct experiments in many different areas. Examples include alcohol, medicines and drugs, driving with disabilities, Human-Machine-Interaction, fatigue, road design, and vehicle design. A driving simulator is designed to imitate driving a real vehicle. The driver interface can be realized with a real vehicle cabin or only a seat with a steering wheel and pedals, and anything in between. The surroundings are presented for the driver on a screen. It is important that the performance of the simulator vehicle, the visual representation, and the behavior of surrounding objects be as realistic as possible. For example, it is important that the ambient vehicles behave in a realistic and trustworthy way. The first aim of the project is to develop a traffic simulation framework that is able to generate and simulate these surrounding vehicles.
Microscopic simulation of traffic is one possibility for simulating these ambient vehicles. Micro-simulation has become a very popular and useful tool in studies of traffic systems. Micro-simulation models are time discrete models which simulate individual vehicle/driver units. The behavior of vehicles/drivers and the interaction between these vehicles/drivers are simulated using different sub-models for car-following, lane-changing, speed adaptation, etc. The sub-models use the current road and traffic situation as inputs and generate individual driver decisions regarding, for example, acceleration and preferred lane.
The main reason for choosing driving simulators for conducting driving behavior experiments is often to get increased controllability and reproducibility. In order to ensure high reproducibility, the behavior of the surrounding road-users is often strictly controlled. This comes with the price of limited realism regarding the surrounding vehicles’ behavior and limitations in the complexity of the scenario situations, due to both the complexity of the scenario programming and the required programming effort. The complexity of programming can be decreased and realism increased by giving the surrounding road-users more autonomy. This leads to simulated situations with similar pros and cons as real world situations, i.e. low reproducibility but realistic surroundings. However, this environment is both safer and still more controllable than the real world. Our hypothesis is that is possible to achieve both a high realism and high reproducibility by combining periods with “fully” autonomous simulated road-users with periods with only controlled simulated road-users. The second aim of the project is therefore to develop an alternative design methodology for driving simulator experiments in which periods with “fully” autonomous simulated road-users are combined with periods with only controlled simulated road-users.
Partners: Jonas Jansson and Laban Källgren, Swedish National Road and Transport Research Institute (VTI), Stephané Espié, INRETS, frankrike
Contact: Johan Janson Olstam
- Janson Olstam, Johan (2003), “Traffic generation for the VTI Driving Simulator”, In Proceedings of the Driving Simulator Conference – North America (DSC-NA), Dearborn, USA.
- Janson Olstam, Johan (2005). “Simulation of rural road traffic for driving simulators”, in Proceedings of the 84th annual meeting of the Transportation Research Board, Washington, USA.
- Janson Olstam, Johan (2006). “Generation and simulation of surrounding vehicles in a driving simulator”, in Proceedings of the Driving Simulator Conference (DSC’06), Paris, France.
- Janson Olstam, Johan (2006). “Simulation of vehicles in a driving simulator using microscopic traffic simulation”, in Proceedings of the 2nd International Symposium on Transport Simulation, Lausanne, Switzerland.
- Janson Olstam, J. and S. Espié (2007), “Combination of autonomous and controlled vehicles in driving simulator scenarios”, In Proceedings of Road Safety and Simulation (RSS 2007).
- Janson Olstam, J., Lundgren, J., Adlers, M. and P. Matstoms (2008). “A framework for simulation of surrounding vehicles in driving simulators”, accepted for publication in ACM-TOMACS.
Rural Road Traffic Simulation
Participants: Andreas Tapani, Jan Lundgren
Traffic micro-simulation is a useful tool in the analysis of various traffic systems. The main focus of this work is simulation of rural road environments. A specialized simulation model for rural roads, RuTSim, is developed within this project. Current research is, among other things, concerned with simulation of driver assistance systems and other ITS-applications and their effects on rural road traffic.
Partners: Pontus Matstoms (VTI) and Arne Carlsson (VTI).
Contact: Andreas Tapani
Participant: Johanna Törnquist Krasemann
The research project ELVIS aims at analyzing how the Swedish railway system can be more effective by using longer and/or heavier cargo trains. This will be evaluated by performing a number of demonstration scenarios where the electricity consumption is measured and analyzed, along with a cost benefit analysis and a network capacity analysis. The project name “ELVIS” can be read as "el vis" (Eng. ”wise w.r.t. electricity”) and it runs during 2011-2014. The project is coordinated by VTI and Linköping University is managing WP3, where the network capacity usage is analyzed. The project is financed within the research program ”Energieffektivisering inom transportområdet - demonstrationsprojekt" (Energimyndigheten, 25%) and with time by Trafikverket, Skogsindustrierna and a number of larger Swedish forest companies.
Contact: Johanna Törnquist Krasemann
Global optimization of congestion pricing schemes
Participant: Joakim Ekström
Road pricing is commonly discussed as one possible tool for solving congestion problems in larger urban areas. Optimal congestion charges, maximizing the social welfare, can be theoretically computed by letting the road users pay a fee equal to the delay (measured in terms of a monetary unit) a road user imposes on his or her fellow road users. Although optimal charges can be computed, it is in practice difficult to find a way to charge each road user the optimal fee. Therefore pricing schemes are usually devised in terms of toll rings, area pricing or kilometer charges, with the major design parameters in the pricing schemes being how much, where and when to charge. By altering the design parameters in the pricing scheme it is possible to alter the road users travel behavior in such a way that the overall social welfare is maximized.
To find the optimal toll locations and toll levels in a congestion pricing scheme based on road tolls, which maximizes the social welfare, can be formulated as a mathematical program with equilibrium constrains (MPEC). This optimization problem is closely related to network design problems arising within transportation research, and is considered as a challenging optimization problem to solve. The problem is usually addressed by different heuristic approaches, which are able to find feasible solutions but not prove optimality or estimate the quality of the solutions obtained. In this project we instead investigate the possibility to apply a global optimization approach, based on approximation of the non-convex functions, in the MPEC-formulation, by piecewise linear ones. The MPEC is then transformed into a mixed integer linear program which can be solved by commercially available software.
Partners: Agachai Sumalee, Hong Kong Polytechnic University
Contact: Joakim Ekström
Publications: “Optimizing toll locations and levels using a mixed integer linear approximation approach”, Transportation Research Part B, Vol. 46, No 7, 2012, pp. 834-854. (J. Ekström, A. Sumalee, H. K. Lo)
Link flow detector placement
Participants: Jan Lundgren and Anders Peterson
Link flow measurements supply reliable information on the current traffic volumes and are often used to estimate Origin–Destination (OD) matrices, which specify the travel demand for every pair of origin and destination zone in a traffic network. The flow measurements are collected from detectors which are placed on some links in the network. Unfortunately there are not enough detectors to cover all links. Typically only some five percent of the link flows. An interesting question is how these links are chosen.
In this research project we study how the placement of the link flow detectors impact the reliability of the estimated OD-matrix and try to formulate the detector placement problem as to ensure the best possible quality of the estimated OD-matrix.
Partner: Torbjörn Larsson, Department of Mathematics, Linköping University
Contact: Anders Peterson
DORIS - Design of optimal road charging systems
Participants: Joakim Ekström and Clas Rydergren
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. The benefit of the system will be influenced by the set-up and operation cost of the system, the number of tolled links and their toll levels.
In this project we aim to develop methods for finding congestion pricing schemes, which will maximize the benefit of the system, in terms of social surplus. The suggested methods should be applicable for large scale networks.
Partner: Leonid Engelson, Center for Traffic Research (CTR)
Contact: Joakim Ekström
Current use and future development of models for multimodal traffic systems
Participants: Clas Rydergren
The traffic demands modelling system SAMPERS is an integrated system for car ownership, demand modelling, impact calculation, cost benefit analysis and accessibility calculation. SAMPERS covers demand modelling for road, rail, train and sea and detailed modelling of road and train. The system has been in use from 1998. This project aims at documenting the use of this and other traffic modelling systems in Sweden. The outcome of the project is information on how the system can be improved, and which requirements shall be put on future development of this system, or forthcoming systems with the same purpose.
Partners: Staffan Algers and Lars-Göran Mattsson, KTH and Bo Östund, TFK.
Financed by: Swedish Rail Administration and Swedish Road Administration
Contact: Clas Rydergren
Realtime-GIS for transportation
Participants: Anders Wellving
A realtime-GIS makes it possible to collect, store, process and present positions for vehicles and goods in real time. These systems depends on a combination of GIS, telecommunication and positioning devices. This project contains an inventory of current technology, applications and development trends for realtime-GIS. The purpose is to describe the state-of-art and to give idéas for future research projects.
Contact: Anders Wellving
Models and Methods for Estimation of Origin–Destination Matrices
Participants: Jan Lundgren, Anders Peterson and Clas Rydergren
Origin–Destination (OD) matrices, which specify the travel demand for every pair of origin and destination zone in a traffic network, are needed for most types of analyses in the field of traffic management. Typical applications include evaluation capacities, travel times and emissions in the present and future traffic network, as well as the evaluation of traffic control policies and investigation of the effects of travel information systems. In this project, we are trying to estimate the OD matrices based on the information captured by link flow observations. The relation between the OD matrix and the link flows is described by a traffic assignment model, which is based on assumptions on how the travelers are split up onto different routes and how the propagate over time in the network.
The estimation problem is formulated as a bilevel structure, where the upper level changes the OD matrix and the lower level computes the induced flows on the links, according to the given assignment model. The static case, where all quantities are assumed to represent a steady state, for example the morning peak period, has been studied for a long time. In this project we try to expand the ideas for covering a dynamic (time-dependent) situation. Supporded by Swedish Road Administration (Vägverket).
Partner: Ingmar Andreasson och Wilco Burghout, Center for Traffic Research (CTR)
Contact: Anders Peterson
- Lundgren, J.T., and A. Peterson (2008) “A heuristic for the bilevel origin–destination matrix estimation problem”, Transportation Research Part B 42, pp 339-354.
- Peterson, A. (2003) “The origin–destination matrix estimation problem — analysis and computations”, doctoral dissertation, Linköping Studies in Science and Technology. Dissertations, No. 1102, Department of Science and Technology, Linköping University, Norrköping.
- Lundgren, J.T., Peterson, A., and C. Rydergren (2005) “A heuristic for the estimation of time-dependent origin–destination matrices from traffic counts”, in: Advanced OR and AI Methods in Transportation, Proceedings of the 10th Jubilee Meeting of the EURO Working Group on Transportation, Poznan, Poland, 13–16 September 2005, A. Jaszkiewicz et al. (eds.), Publishing House of Poznan University of Technology, Poznan, Poland, pp 242–246.
- Peterson, A. (2003) “Origin–destination matrix estimation from traffic counts”, licentiate thesis, Linköping Studies in Science and Technology. Theses, No. 1057, Department of Science and Technology, Linköping University, Norrköping.
- Lundgren, J.T., Peterson, A., and S. Tengroth (2003) “Methods for pre-adjusting time-dependent origin–destination matrices”, in proceedings of the 10th World Congress and Exhibition on Intelligent Transportation Systems and Services, Madrid, Spain, 16–20 November, 2003, Paper No. 2436.
Estimation of volume delay functions for urban environments based on an analytical intersection model
Participants: Johan Janson Olstam and Clas Rydergren
This project deals with methods 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 a road link changes with traffic demand. The developed 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.
Partners: Pontus Matstoms, Swedish National Road and Transport Research Institute (VTI)
Contact: Johan Janson Olstam
- Janson Olstam, J. Rydergren, C. and P: Matstoms (2008). “Estimation of volume delay functions for urban environments using an analytical intersection model”, In Proceedings of the 87th annual meeting of the Transportation Research Board, Washington, USA.
- Janson Olstam, J. and P. Matstoms (2006), Nya V/D-funktioner på väg. Preliminära funktioner för tätortsmiljöer baserade på ny metod (New V/D-functions on the way, Preliminary functions for urban road environments based on a new method, in Swedish), VTI-rapport 571.
Toward the development of techniques for designing equitable, efficient & acceptable urban transport systems
Participant: Clas Rydergren
Transport planners currently face a major challenge to devise future transport plans to meet multiple expectations and objectives. In doing so, they must consider the complex nature of the transport system. In this research, we aim to develop a decision-support tool for enhancing the understanding of various transport policies and finding appropriate transport measures to ensure a better quality transport system in the future. The research concentrate on developing a suitable model for the urban transport system, together with flexible mathematical forms for expressing efficiency, equity and public acceptability considerations in the form of objectives and constraints. In order to study the impact of various policies, sensitivity analysis expressions of the inputs to the model system on the efficiency, equity and acceptability considerations, is derived. Supported by Volvo Research Foundation, Volvo Educational Foundation and Dr Pehr G. Gyllenhammars Research Foundation.
Partners: Michael Patriksson, Chalmers, Göteborg, Dawid Watling, Richard Connors, Agachai Sumalee, Institute for transport studies, Leeds university, Leeds.
Contact: Clas Rydergren
Development and Analysis of integrated Public Transportation
Participants: Carl Henrik Häll, Jan Lundgren, Anders Wellving, Peter Värbrand
This project studies how traditional fixed-route public transportation can be combined with demand responsive services to obtain an integrated public transportation service, in this way making use of the advantages of both the traditional types. The purpose is to increase the quality of the public transport service for ordinary passengers, for disabled and elderly people, as well as for people in need of special transport service. Models and systems based on optimisation and simulation is used to develop, analyse and evaluate different designs and operating policies of integrated public transportation systems.
Partners: Bengt Holmberg (Lund Institute of Technology), Mats Börjesson (Transportidé i Uppsala AB), Yngve Westerlund (Logistikcentrum), the city of Gävle and VINNOVA.
Contact: Carl-Henrik Häll
- Häll, C.H., Lundgren, J.T. & Värbrand P. (2008). Evaluation of an integrated public transport system: a simulation approach. Accepted for publication in Archives of Transport.
- Häll, C.H., Andersson, H., Lundgren, J.T. & Värbrand, P. (2008). The integrated dial-a-ride problem. Submitted to: Public Transport: Planning and Operations.
- Häll, C.H., Lundgren, J., & Värbrand, P. (2005). Simulation and evaluation of integrated public transport. In: Advanced OR and AI Methods in Transportation, Proceedings of the 10th Jubilee Meeting of the EURO Working Group on Transportation, 271-275. Poznan, Poland. ISBN: 83-7143-239-5; A. Jaszkiewicz, et al. eds.
- Häll, C.H. (2005). Simulations of an integrated public transport service. FINAL, Delredovisning 9. www.port.se/final (2008-04-11).
- Häll, C.H. (2004). Integrated public transport systems. Technical report for Vinnova within the project ”Integrerad kollektivtrafik”.
Last updated: Wed Feb 01 21:51:25 CET 2017