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  • 1.
    Börjesson, Maria
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS.
    Eliasson, Jonas
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport and Location Analysis. KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS.
    Kristoffersson, Ida
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Trängselskatt på Essingeleden minskar trängseln kraftigt. PM till TV4 201104252011Report (Other academic)
  • 2.
    Börjesson, Maria
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS.
    Kristoffersson, Ida
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Estimating welfare effects of congestion charges in real world settings2011In: Journal of Urban Economics, ISSN 0094-1190, E-ISSN 1095-9068Article in journal (Other academic)
  • 3.
    Börjesson, Maria
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS.
    Kristoffersson, Ida
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Welfare effects of Stockholm congestion charges using dynamic network assignment2011In: Proceedings of the European Transport Conference, Glasgow, UK, 2011Conference paper (Refereed)
    Abstract [en]

    According to the standard textbook analysis, drivers as a group will be worse off with congestion charging if not compensated by revenues. This result is confirmed by an analysis of the Stockholm congestion charging scheme using a static model with homogenous users. However, both this static model and the standard textbook analysis omit three important factors: taste heterogeneity, effects of charges on the larger network arising from less blocking back of upstream links and behavioural adjustments in the temporal dimensions. Taking account of these factors, using a dynamic model with heterogeneous users in a large-scale network, we find that drivers as a group benefit directly from the charging scheme in Stockholm. This paper investigates the importance of the three factors omitted in the standard textbook and the static model analysis in the Stockholm case, finding that all three add significantly to the benefit of the charges.

  • 4.
    Börjesson, Maria
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS.
    Kristoffersson, Ida
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Welfare effects of Stockholm congestion charges using dynamic network assignment2012In: Proceedings of the Transportation Research Board (TRB) 91st Annual Meeting, Washington D.C. USA, 2012Conference paper (Refereed)
    Abstract [en]

    According to the standard textbook analysis, drivers as a group will be worse off with congestion charging if not compensated by revenues. This result is confirmed by an analysis of the Stockholm congestion charging scheme using a static model with homogenous users. However, both this static model and the standard textbook analysis omit three important factors: taste heterogeneity, effects of charges on the larger network arising from less blocking back of upstream links and behavioural adjustments in the temporal dimensions. Taking account of these factors, using a dynamic model with heterogeneous users in a large-scale network, we find that drivers as a group benefit directly from the charging scheme in Stockholm. This paper investigates the importance of the three factors omitted in the standard textbook and the static model analysis in the Stockholm case, finding that all three add significantly to the benefit of the charges.

  • 5.
    Börjesson, Maria
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS.
    Kristoffersson, Ida
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Welfare effects of Stockholm congestion charges using dynamic network assignment2011In: Proceedings of the 2011 Conference and the Summer School, Stockholm, Sweden, 2011Conference paper (Refereed)
    Abstract [en]

    According to the standard textbook analysis, drivers as a group will be worse off with congestion charging if not compensated by revenues. This result is confirmed by an analysis of the Stockholm congestion charging scheme using a static model with homogenous users. However, both this static model and the standard textbook analysis omit three important factors: taste heterogeneity, effects of charges on the larger network arising from less blocking back of upstream links and behavioural adjustments in the temporal dimensions. Taking account of these factors, using a dynamic model with heterogeneous users in a large-scale network, we find that drivers as a group benefit directly from the charging scheme in Stockholm. This paper investigates the importance of the three factors omitted in the standard textbook and the static model analysis in the Stockholm case, finding that all three add significantly to the benefit of the charges.

  • 6. Ekström, J.
    et al.
    Kristoffersson, Ida
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS.
    Quttineh, N. -H
    Surrogate-based optimization of cordon toll levels in congested traffic networks2016In: Journal of Advanced Transportation, ISSN 0197-6729, E-ISSN 2042-3195, Vol. 50, no 6, p. 1008-1033Article in journal (Refereed)
    Abstract [en]

    The benefit, in terms of social surplus, from introducing congestion charging schemes in urban networks is depending on the design of the charging scheme. The literature on optimal design of congestion pricing schemes is to a large extent based on static traffic assignment, which is known for its deficiency in correctly predict travel times in networks with severe congestion. Dynamic traffic assignment can better predict travel times in a road network, but are more computational expensive. Thus, previously developed methods for the static case cannot be applied straightforward. Surrogate-based optimization is commonly used for optimization problems with expensive-to-evaluate objective functions. In this paper, we evaluate the performance of a surrogate-based optimization method, when the number of pricing schemes, which we can afford to evaluate (because of the computational time), are limited to between 20 and 40. A static traffic assignment model of Stockholm is used for evaluating a large number of different configurations of the surrogate-based optimization method. Final evaluation is performed with the dynamic traffic assignment tool VisumDUE, coupled with the demand model Regent, for a Stockholm network including 1240 demand zones and 17 000 links. Our results show that the surrogate-based optimization method can indeed be used for designing a congestion charging scheme, which return a high social surplus.

  • 7.
    Eliasson, Jonas
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Börjesson, Maria
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS.
    Hamilton, Carl
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Kristoffersson, Ida
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS.
    Flexibel trängselskatt ger flyt åt Stockholmstrafiken: DN Debatt2012In: Dagens nyheter, ISSN 1101-2447Article, book review (Other (popular science, discussion, etc.))
    Abstract [en]

    Omstridd skatt fyller sex. Trängselskattens påverkan på trafiken är till och med större i dag än när den infördes. Att många ändå upplever att köerna blivit längre beror på flera stora byggprojekt som påverkar kapaciteten på vägarna. Trängselskatten bör därför bli mer flexibel och anpassas efter vägarbeten, årstider etc. Essingeleden bör också snarast avgiftsbeläggas. Det skulle enkelt minska trafiken där med 13 procent och göra Stockholm effektivare, renare och trevligare, skriver fyra transportforskare.

  • 8.
    Engelson, Leonid
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS. KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport and Location Analysis.
    Kristoffersson, Ida
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Saifuzzaman, Mohammad
    de Palma, André
    Motamedi, Kiarash
    Comparison of two dynamic transportation models: The case of Stockholm congestion charging2012Conference paper (Refereed)
    Abstract [en]

    This paper reviews the transportation models used for predicting impacts of congestion charging in European cities and carries out in-depth comparison of two such models, METROPOLIS and SILVESTER. Both are mesoscopic dynamic models involving modal split and departure time choice calibrated for the Stockholm baseline situation without charges and applied for modeling effects of congestion charging. The results obtained from the two models are mutually compared and validated against actual outcome of the Stockholm congestion charging scheme.  Both models provide significant improvement in realism over static models. However results of cost benefit analysis differ substantially

  • 9.
    Engholm, Albin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Centres, Integrated Transport Research Lab, ITRL.
    Pernestål, Anna
    KTH, School of Industrial Engineering and Management (ITM), Centres, Integrated Transport Research Lab, ITRL.
    Kristoffersson, Ida
    VTI Statens väg- och transportforskningsinstitut.
    System-level impacts of self-driving vehicles: terminology, impact frameworks and existing literature syntheses2018Report (Other academic)
    Abstract [en]

    The intention with this report is to contribute toward the development of systemic and holistic studies of impacts of self-driving vehicles. The report is targeting system-level impacts of self-driving vehicles on the transportation system but also wider societal impacts on factors such as: land-use, public health, energy and emissions, etc. This report is complimentary to two papers that are focused on in-depth literature review of simulation studies  (Pernestål Brenden and Kristoffersson 2018) and future scenario studies of impacts of self-driving vehicles (Engholm, Kristoffersson, and Pernestål Brenden 2018).

    The first aim of the report is to summarize knowledge to enable future design of a high-level conceptual framework for impacts from self-driving vehicles from a systems perspective. The second aim is to summarize knowledge on impacts from self-driving vehicles in a selection of the available literature. The main contributions of the report are the following:

    • A terminology for different types of automated vehicles, connected vehicles and mobility concepts for automated vehicles is presented
    • Frameworks for classifying system-level impacts from SDVs in the existing literature are summarized and analyzed
    • Existing literature studies on system-level impacts from SDVs are synthesized and common themes and gaps in current research are analyzed

    The terminology proposed in this report distinguishes between different types of automated and connected vehicles and is primarily intended as a tool to enable stringent analysis in this report when analyzing literature that apply different terminologies. Two frameworks for classifying system-level impacts are identified and compared. The analysis of the frameworks covers their scope, specification of mechanisms generating system impacts and briefly reviews their applicability as a starting point for developing a systems model of impacts from self-driving vehicles. The review of existing literature syntheses shows that there is a large variation in availability on literature for different system impacts. Impacts on road safety, road capacity and vehicle ownership forms are well studied. Examples of less studied impacts are costs of ownership, public health, infrastructure, air pollution and accessibility. The review identifies several contractionary mechanisms and effects that can affect various system-level impacts. The results of the review highlight the need to approach impact assessments of self-driving vehicles from a systemic and holistic point of view.

  • 10.
    Kristoffersson, Ida
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics. KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Traffic Research, CTR.
    Congestion Charging in Urban Networks: Modelling Issues and Simulated Effects2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    One of the major challenges cities face today, in their development towards sustainable urban areas, is the need for an efficient and environmentally friendly transport system. This transport system should manage to tie together the city without strong adverse impact on urban environment, air-quality and climate change. The specialized labour (and leisure) market, typical of a large urban area, exaggerates the need for efficient travel, as it is increasingly difficult to live and work within short distances.   

    The use of demand management tools has become more frequent in transport planning with this development towards more sustainable cities. Whereas investing in new capacity was previously the main response to increased demand for travel, there is a much broader range of policies in use today. One of these demand management tools is congestion charging. Singapore was first to implement congestion charging and during the last decade it was followed by London and Stockholm, with increasing support from the citizens as a consequence. Many other cities have performed feasibility studies for introduction of congestion charging. 

    The development of transport models for prediction of demand management tools, such as congestion charging, has however not been able to keep up with this change in kind of policy. Transport models that were developed for prediction and evaluation of infrastructure investments, such as new motorways, are often used to forecast effects of policies aimed at managing demand, which too often results in poor prediction.

    This thesis focuses on the needs for modelling of congestion charging. The state-of-practice models used before implementation in Singapore, London and Stockholm are reviewed, as well as more advanced dynamic models developed for prediction of congestion charging and other demand management tools. A number of gaps in the modelling of congestion charging are described and a new model called SILVESTER is developed, which closes some of these gaps. In particular, SILVESTER involves dynamic mesoscopic modelling of traffic flows, flexible departure times and users with heterogeneous preferences.

    The thesis describes the implementation of SILVESTER and considers and compares different methods of demand aggregation in order to reduce run-time of the large-scale dynamic model (Paper I). It also describes how preferred departure times of road users can be determined in calibration such that consistency exists between the departure time choice model and dynamic traffic flows which are input to assignment (Paper II). The unique implementation of congestion charging in Stockholm gives the possibility to validate SILVESTER on real-world measurement of reductions in traffic flow and behavioural adjustments to the charges (Paper III). SILVESTER is then used to analyse several modified versions of the Stockholm congestion charging scheme and to compare welfare and equity effects of the different schemes. It is shown that the welfare of the current scheme could be improved if charges were allowed to differ by location and driving direction (Paper IV). It is shown that the benefits of congestion charges calculated using SILVESTER are greater than the benefits calculated with a static model. Finally, the reasons for the greater benefits are investigated (Paper V).

  • 11.
    Kristoffersson, Ida
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics. KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Traffic Research, CTR.
    Impacts of time-varying cordon pricing: Validation and application of mesoscopic model for Stockholm2013In: Transport Policy, ISSN 0967-070X, E-ISSN 1879-310X, Vol. 28, no SI, p. 51-60Article in journal (Refereed)
    Abstract [en]

    This paper uses a simulation model to compare traffic and welfare effects of changes to the charging schedule currently in use in Stockholm. In particular, a step toll is compared to its flat counterpart at two charging levels. The increments between steps are also increased in a peaked step toll scenario. Furthermore, results from simulation of the current toll ring are compared to real-world measurements in a first attempt to validate model predictions regarding impacts of a time-varying congestion charging scheme. In the model, car users have the possibility to respond to congestion charging by changing departure time, route or switch to public transport and travel times are calculated using mesoscopic traffic simulation. Validation shows that departure time choice adjustments because of congestion charging are overestimated by the model that is based on stated preference data. This warrants further research on discrepancies between stated and revealed adjustments to congestion charging. The current step toll reaches the highest social benefit estimate in model predictions, but differences in traffic effects between the current step toll and its flat counterpart are rather small. Furthermore, results show that demand changes occur in the model to a considerably greater extent for trips with low value of time. The differences in welfare effects is for that reason large for different trip purposes, indicating the importance of accounting for heterogeneous trips when modelling effects of congestion charges.

  • 12.
    Kristoffersson, Ida
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301).
    Incorporation of Departure Time Choice in a Mesoscopic Transportation Model for Stockholm2009Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Travel demand management policies such as congestion charges encourage car-users to change among other things route, mode and departure time. Departure time may be especially affected by time-varying charges, since car-users can avoid high peak hour charges by travelling earlier or later, so called peak spreading effects. Conventional transport models do not include departure time choice as a response. For evaluation of time-varying congestion charges departure time choice is essential.

    In this thesis a transport model called SILVESTER is implemented for Stockholm. It includes departure time, mode and route choice. Morning trips, commuting as well as other trips, are modelled and time is discretized into fifteen-minute time periods. This way peak spreading effects can be analysed. The implementation is made around an existing route choice model called CONTRAM, for which a Stockholm network already exists. The CONTRAM network has been in use for a long time in Stockholm and an origin-destination matrix calibrated against local traffic counts and travel times guarantee local credibility. On the demand side, an earlier developed departure time and mode choice model of mixed logit type is used. It was estimated on CONTRAM travel times to be consistent with the route choice model. The behavioural response under time-varying congestion charges was estimated from a hypothetical study conducted in Stockholm.

    Paper I describes the implementation of SILVESTER. The paper shows model structure, how model run time was reduced and tests of convergence. As regards run time, a 75% cut down was achieved by reducing the number of origin-destination pairs while not changing travel time and distance distributions too much.

    In Paper II car-users underlying preferred departure times are derived using a method called reverse engineering. This method derives preferred departure times that reproduce as well as possible the observed travel pattern of the base year. Reverse engineering has previously only been used on small example road networks. Paper II shows that application of reverse engineering to a real-life road network is possible and gives reasonable results.

  • 13.
    Kristoffersson, Ida
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301).
    Engelson, Leonid
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301).
    A Dynamic Transportation Model for the Stockholm Area: Implementation Issues Regarding Departure Time Choice and OD-pair Reduction2009In: Networks and Spatial Economics, ISSN 1566-113X, E-ISSN 1572-9427, Vol. 9, no 4, p. 551-573Article in journal (Refereed)
    Abstract [en]

    Road traffic congestion is an increasing problem in urban areas. Building new roads often attracts latent demand and turns parts of the city into building sites for several years. Policy measures that stimulate more effective use of the existing network, such as variable road pricing, are therefore becoming increasingly popular among policy makers and citizens. These measures are often aimed at changing the temporal distribution of traffic. Yet transportation models taking departure time choice into account are rare. This paper describes the implementation of an urban transportation application for Stockholm, which includes departure time choice, mode choice and time dependent network assignment. Through iterations between demand and supply the objective of the transportation model is to forecast effects of congestion charges, intelligent transport systems and infrastructure investments on departure time choice. The complexity of large-scale departure time choice modelling and dynamic traffic assignment is high, which results in very long run times. Therefore, research on how to increase model efficiency is needed. This paper describes choices made in the implementation for a more efficient model.

  • 14.
    Kristoffersson, Ida
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Engelson, Leonid
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS. KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport and Location Analysis.
    Alternativa vägavgiftssystem och individers resval2011Report (Other academic)
  • 15.
    Kristoffersson, Ida
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Engelson, Leonid
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport and Location Analysis. KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS.
    Alternative Congestion Charging Schemes and their Equity Effects: Results of Simulations for Stockholm2011In: Transportation Research Part A: Policy and Practice, ISSN 0965-8564, E-ISSN 1879-2375Article in journal (Other academic)
  • 16.
    Kristoffersson, Ida
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics. KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Traffic Research, CTR.
    Engelson, Leonid
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Traffic Research, CTR.
    Alternative road pricing schemes and their equity effects: Results of simulations for Stockholm2011In: Proceedings of the TRB 90th Annual Meeting, Washington, D.C., 2011Conference paper (Refereed)
    Abstract [en]

    This paper uses a newly developed transport model to analyze effects of alternative road pricing schemes. The responses to road pricing included in the model are departure time, mode and route choice. Traffic analysis is performed on a large urban network of Stockholm using mesoscopic simulation. The compared pricing schemes differ in toll location and charged amount. Through calculation of consumer surplus per geographical zone, effects of the road pricing schemes are analyzed per income group and geographical area in order to study equity effects. Simulation results suggest that road pricing can be both regressive and progressive depending on the design of the pricing scheme, this even before the use of revenues to compensate users. Results also indicate that there can be a disagreement between which pricing scheme is preferable from a congestion mitigating point of view and which is preferable when looking at equity effects.

  • 17.
    Kristoffersson, Ida
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering. VTI.
    Engelson, Leonid
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Estimating preferred departure times of road users in a large urban network2018In: Transportation, ISSN 0049-4488, E-ISSN 1572-9435, Vol. 45, no 3, p. 767-787Article in journal (Refereed)
    Abstract [en]

    In order to reliably predict and assess effects of congestion charges and other congestion mitigating measures, a transportation model including dynamic assignment and departure time choice is important. This paper presents a transport model that incorporates departure time choice for analysis of road users’ temporal adjustments and uses a mesoscopic traffic simulation model to capture the dynamic nature of congestion. Departure time choice modelling relies heavily on car users’ preferred times of travel and without knowledge of these no meaningful conclusions can be drawn from application of the model. This paper shows how preferred times of travel can be consistently derived from field observations and conditional probabilities of departure times using a reverse engineering approach. It is also shown how aggregation of origin–destination pairs with similar preferred departure time profiles can solve the problem of negative solutions resulting from the reverse engineering equation. The method is shown to work well for large-scale applications and results are given for the network of Stockholm.

  • 18.
    Kristoffersson, Ida
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics.
    Engelson, Leonid
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics.
    Estimating preferred departure times of road users in a real-life network2008In: Proceedings of the  European Transport Conference 2008, 2008Conference paper (Refereed)
    Abstract [en]

    The demand for travel continues to increase in European cities of today, which results in long car travel times and highly congested road networks, especially during the morning and afternoon peak periods. The congested car system gives rise to high emissions of particles and greenhouse-gases, which is negative for both the local and global environment. Congestion also causes an uncertain travel time, something that in the latest years has been recognised as a major factor in car-users perception of trip disutility. Congestion is time-dependent in nature. Therefore, not only the spatial distribution of trips over the network is important in analysis and prediction, but also the temporal distribution of trips. A traditional congestion-relieving strategy such as a capacity expansion often has an impact on when people travel, since shorter travel times during the peak hour can attract traffic from the peak shoulders. The temporal effects are even more pronounced for the new policy measures gaining ground today, e.g. variable road pricing. Most variable road pricing systems aim at moving traffic from the peak hour to the peak shoulders, so called peak spreading. The means by which this is done is by charge differentiation: it is most expensive to travel at the most congested point in time. However, most large-scale transport planning models in use today are static and changes in the temporal distribution of trips are not considered. It is therefore likely that false conclusions are drawn when using these models to evaluate the ability of different pricing schemes or infrastructure investments to alleviate congestion.SILVESTER – A Dynamic Transport ModelTo better model the temporal distribution of traffic has been the basis in the development of SILVESTER (SImuLation of choice betWEen Sarting TimEs and Routes), which is a dynamic transport model for the Stockholm area. In SILVESTER road network conditions during the extended morning peak period (06:30-09:30) are modelled. The morning is divided into twelve 15-minute time intervals and a departure time choice model allocates trips to each interval depending on their attractiveness. The attractiveness of a time interval is determined by its corresponding travel time, travel time uncertainty, monetary cost and how close it is to the preferred time interval (PDT) of the traveller. The travellers can also choose to start before 06:30 or after 09:30. Mode choice is partially modelled by introducing the possibility for car-users to switch to public transport if it is perceived as a better option than any of the time intervals. It is distinguished between three trip purposes: business trips, trips with fixed schedule and school trips, and trips with flexible schedule and other trips. In SILVESTER iteration towards a general equilibrium between supply and demand is performed. The supply quantities (travel times, uncertainties etc.) are calculated with the mesoscopic dynamic traffic assignment model CONTRAM, whereas the demand for each time interval and public transport alternative is calculated with a mixed logit discrete choice model. A calibrated origin-destination-matrix (OD-matrix) for the Stockholm CONTRAM network exists and is based mainly on traffic counts but also on travel times for some selected OD-pairs. Calibration of Preferred Departure TimesEven though many trip-timing models use the concept of schedule delay, which is defined as the deviation from a preferred departure/arrival time, little work has been done on how to find the PDT-distribution when applying the model. For estimation the survey respondents can be asked to state their preferred time of travel, but for large-scale applications similar studies are expensive and time consuming. Previous work has often assumed a simplified distribution, such as all travellers in a market segment having the same PDT. Without calibration of PDT’s, e.g. using only a simplified exogenous assumption, the predictive capability of the transport model is questionable. Instead of making an exogenous assumption about the PDT-distribution this paper uses a reverse engineering approach to reveal PDT’s from the observed departure times of the reference situation. It is the combination of the estimated departure time choice model, the travel conditions and the observed departure times that can be used to get information about the PDT’s. Once the PDT’s have been calibrated for the reference situation they can be used in the evaluation of a congestion relieving strategy. This paper will present calibration methodology, obstacles overcome on the way and calibration results. It will also discuss future work in which the calibrated departure time choice model will be used to improve the design (charge levels and time periods) of a pricing scheme.

  • 19.
    Kristoffersson, Ida
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301). KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Traffic Research, CTR.
    Engelson, Leonid
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301). KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Traffic Research, CTR.
    Revealing Preferred Departure Times for Large-Scale Transport Modelling2008In: Proceedings of the 2008 International Symposium on Travel Demand Management, Vienna-Semmering, Austria, 2008Conference paper (Refereed)
  • 20.
    Kristoffersson, Ida
    et al.
    VTI Swedish National Institute for Road and Transport Research, SE - 102 15 Stockholm, Sweden.
    Pernestål Brenden, Anna
    KTH, School of Industrial Engineering and Management (ITM), Centres, Integrated Transport Research Lab, ITRL.
    Scenarios for the development of self-driving vehicles in freight transport2018In: Proceedings of 7th Transport Research Arena TRA2018, 2018Conference paper (Refereed)
    Abstract [en]

    This paper extends previous research by developing future scenarios for self-driving vehicles and their societal impacts in freight transport using Sweden as a case study. Freight experts from vehicle manufacturers, agencies, universities and hauliers were recruited for a workshop where they assessed the benefits, costs, possibilities and barriers for self-driving vehicles in freight transport. The paper shows that reduction in driver and vehicle costs, reduced number of incidents and more fuel-efficient driving are seen as the main benefits of self-driving vehicles in freight transport, and increased vehicle costs, lost jobs, reduced degree of filling and more transport as the main costs. Furthermore, reduced drivers’ costs, more hours-of-service and new business models are identified as the main drivers of the development and traffic management, small hauliers, loading and unloading and cross-border transport as the main barriers. The paper also integrates the description of possible developments of self-driving vehicles in freight transport into the four future scenarios developed for passenger transport in Sweden.

  • 21.
    Susilo, Yusak Octavius
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, System Analysis and Economics.
    Prelipcean, Adrian Corneliu
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Geoinformatics.
    Gidofalvi, Gyözö
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Geoinformatics.
    Allström, Andreas
    Sweco.
    Kristoffersson, Ida
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS.
    Widell, Jenny
    Sweco.
    Lessons from a trial of MEILI, a smartphone based semi-automatic activity-travel diary collector, in Stockholm city, SwedenManuscript (preprint) (Other academic)
    Abstract [en]

    This paper describes the lessons learned from the trial of MEILI, a smartphone based semi-automatic activity-travel diarycollection system, in Stockholm city, Sweden. The design of the system, together with state-of-the-art improvements of different elements of the tool, are presented before and after the trial to better illustrate the improvements based on the lessons learned. During the trial, both MEILI and a paper-based diary captured about 65% of the total number of detected trips, but only about half of the trips were captured by both systems. The unmatchable trips are partly due to different activity declaration and system specific destination specification, i.e., a verbose specification of address in the paper-and-pencil survey and a point of interest selection / declaration in MEILI. In terms of subjective appreciation, the user experiences vary greatly between the different participants in the pilot. Presumably, this is mainly due to different level of IT-knowledge of the respondents, but also due to the occasionally non-uniform behaviour of the location collection service caused by hardware and / or software difficulties. Based on these inputs, further web and support system improvements have been implemented for future trials.

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