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  • 1.
    Abate, Megersa
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics Stockholm.
    Determinants of Capacity Utilisation in Road Freight Transportation2014In: Journal of Transport Economics and Policy, ISSN 0022-5258, E-ISSN 1754-5951, Vol. 48, p. 137-152Article in journal (Refereed)
    Abstract [en]

    Recent performance indicators in the European road freight transport sector show there is an excess capacity. To shed light on this, this paper studies two aspects of capacity utilisation in trucking: the extent of empty running and the load factor. Using a joint econometric modelling framework, the paper shows that they can be explained as a function of haul, carrier, and truck characteristics. For estimation, a unique dataset from the Danish heavy vehicle trip diary was used. The results indicate distance and being a for-hire carrier have a positive effect on capacity utilisation, whereas the effect of truck size is non-linear.

  • 2.
    Abate, Megersa
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics, TEK.
    Does fuel price affect trucking industry’s network characteristics?: evidence from Denmark2014Report (Other academic)
    Abstract [en]

     The 2000s were dominated by rising fuel prices and economic recession. Both had an impact on the structure of the trucking industry and how freight was moved. This paper examines how fuel prices shaped trucking industry’s network characteristics such as the average length of haul, average load, and capacity utilization. In particular, we show the effect of fuel price on average length of haul using 29 quarterly independent surveys from the Danish heavy goods vehicle (HGV) trip diary from 2004 to 2011. The results show that the average length of haul is sensitive to changes in fuel price: a DKK 1 (0.18$) increase in diesel price/liter leads to a 4 percent decrease in the average length of haul in the 2004-2007 period. This implies that firms improve transport efficiency by reducing the number of kilometers needed to transport a tonne of cargo as a short run response to fuel price increases. This result, however, is not confirmed for the years following the 2008 financial crisis. It also depends on where in the distribution of the average length of haul one looks.

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  • 3.
    Abate, Megersa
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics, TEK.
    Economic effects of air transport market liberalization in Africa2016In: Transportation Research Part A: Policy and Practice, ISSN 0965-8564, E-ISSN 1879-2375, Vol. 92, p. 326-337Article in journal (Refereed)
    Abstract [en]

    Although the aviation industry is increasingly becoming important for Africa's economic development and integration, the ability of airlines to access foreign markets remains hindered by restrictive regulatory policies. Attempts have been made to fully liberalize the intra-African air transport market. Except for general assertions about the merits/demerits of liberalization, our empirical understanding of the welfare effects of such polices in Africa remains rudimentary. This study empirically measures the economic effects of air transport liberalization, mainly on two supply side variables: fare and service quality, measured as departure frequency. The empirical models evaluate how air fares and departure frequency respond to measures of openness in air services agreements, while controlling for other determinants. The results show up to 40% increase in departure frequency in routes that experienced some type of liberalization compared to those governed by restrictive bilateral air service agreements. Furthermore, there is a relatively larger increase in departure frequency in routes which experienced partial liberalization compared to fully liberalized ones. This can be explained by the diminishing marginal effect of progressive liberalization on departure frequency. While the effect of liberalization is substantial in improving service quality, there is no evidence of its fare reducing effect.

  • 4.
    Abate, Megersa
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics, TEK.
    Economic effects of air transport market liberalization in Africa2014Report (Other academic)
    Abstract [en]

    Although the aviation industry is increasingly becoming important for Africa's economic development and integration, the ability of airlines to access foreign markets remains hindered by restrictive regulatory policies. Attempts have been made to fully liberalize the intra-African air transport market. Except for general assertions about the merits/demerits of liberalization, our empirical understanding of the welfare effects of such polices in Africa remains rudimentary. This study empirically measures the economic effects of air transport liberalization, mainly on two supply side variables: fare and service quality, measured as departure frequency. The results show up to 40 % increase in departure frequency in routes that experienced some type of liberalization compared to those governed by restrictive bilateral air service agreements. While the effect of liberalization is substantial in improving service quality, there is no evidence of its fare reducing effect.

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  • 5.
    Abate, Megersa
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics Stockholm.
    De Jong, Gerard
    University of Leeds.
    The optimal shipment size and truck size choice: The allocation of trucks across hauls2014In: Transportation Research Part A: Policy and Practice, ISSN 0965-8564, E-ISSN 1879-2375, Vol. 59, p. 262-277Article in journal (Refereed)
    Abstract [en]

    There has been a growing interest in understanding how firms allocate their trucks across hauls, and how this allocation changes under various economic environments. This study investigates how variations in route/haul, carrier and vehicle characteristics affect the optimal vehicle size choice and the associated choice of shipment size. We show that the two choices are derived from the same optimization problem. There can be a continuum of shipment sizes, but decision-makers in freight transport have to choose from a limited number of vehicle alternatives. Therefore, we use a discrete-continuous econometric model where shipment size is modeled as a continuous variable, and vehicle size/type choice as a discrete variable. The results indicate that when faced with higher demand, and during longer trips firms are more likely to use heavier vehicles and ship in larger quantities which suggest that firms are realizing economies of scale and economies of distance. The study also discusses the effect of vehicle operating cost on the vehicle selection process and its policy implications.

  • 6.
    Abate, Megersa
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics Stockholm.
    Vierth, Inge
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics Stockholm.
    de Jong, Gerard
    University of Leeds.
    Joint econometric models of freight transport chain and shipment size choice2014Report (Other academic)
    Abstract [en]

    In freight transportation, decisions regarding the choice of transport mode (or chains of modes) and shipment size are closely linked. Building on this basic insight, in this paper we estimate and review various joint econometric models using the Swedish National Commodity Flow surveys. Robust parameter estimates from this exercise will be used to update the current deterministic Swedish national freight model system (the SAMGODS model) to a stochastic one.

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  • 7.
    Abate, Megersa
    et al.
    World Bank.
    Vierth, Inge
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics.
    Karlsson, Rune
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    de Jong, Gerard
    University of Leeds.
    Baak, Jaap
    dSignificance.
    A disaggregate stochastic freight transport model for Sweden2018In: Transportation, ISSN 0049-4488, E-ISSN 1572-9435, p. 1-26Article in journal (Refereed)
    Abstract [en]

    This paper presents estimation results for models of transport chain and shipment size choice, as well as an implementation of the estimated disaggregate models (for two commodity groups), in the context of the national freight transport model for Sweden. The new model is a disaggregate and stochastic (logit) model, whereas the existing Swedish national model is deterministic. One advantage of the new approach is that it bases the underlying behavior of shippers on a stronger empirical foundation (that is micro-data from the Swedish Commodity Flow Survey, CFS). Another advantage is that it overcomes a well-known disadvantage of deterministic models that lead to implausibly large responses to changes in scenario or policy variables. Although estimation and implementation of aggregate stochastic models were done before, in the context of a national freight transport forecasting model, we think this is the first implementation of disaggregate freight transport chain and shipment size models estimated on choice data for individual shipments, certainly in Europe. We carried out a number of model runs with both versions of the implemented model to compare elasticities and found that transport cost and time elasticities for tonne-km are smaller (in absolute values) in the disaggregate stochastic model than in their deterministic counterparts.

  • 8.
    Abenoza, Roberto F.
    et al.
    KTH.
    Liu, Chengxi
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Cats, Oded
    KTH.
    Susilo, Yusak O.
    KTH.
    What is the role of weather, built-environment and accessibility geographical characteristics in influencing travelers’ experience?2019In: Transportation Research Part A: Policy and Practice, ISSN 0965-8564, E-ISSN 1879-2375, Vol. 122, p. 34-50Article in journal (Refereed)
    Abstract [en]

    We examine the effect of weather, accessibility and built-environment characteristics on overall travel experience as well as the experience with the latest trips. These are factors that are often disregarded in the travel satisfaction literature even though they are believed to largely influence the first mile of the door-to-door trip. This study fills a research gap in investigating all these factors by using, amongst other, a relatively large travel satisfaction survey from years 2009 to 2015 and by focusing on urban and peri-urban geographical contexts, the city and county of Stockholm (Sweden), respectively. The ordered logit model results show that county dwellers living close to a metro station and in well linked-to-all areas report higher overall travel satisfaction evaluations. In addition, precipitation and ground covered with snow have a negative influence on travel satisfaction. Our findings indicate that built-environment characteristics exert a rather weak influence on the travel experience, especially in the peri-urban context. However, some aspects such as living in areas with medium densities, low income and with high safety perceptions around public transport stations are associated with higher satisfaction levels. In turn, areas with single land uses are found to have lower travel satisfactions. These results are important for public transport planners and designers in devising measures to prevent and mitigate the negative outcome of some weather conditions and to conceive better designed transit oriented developments.

  • 9.
    Ahlberg, Joakim
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics Stockholm. Örebro universitet, Handelshögskolan vid Örebro Universitet.
    Analysis of discrete multi-unit, common value auctions: a study of three sealed-bid mechanisms2012Manuscript (preprint) (Other academic)
    Abstract [en]

    This paper proposes a discrete bidding model for both quantities and pricing. It has a two-unit demand environment where subjects bid for contracts with an unknown redemption value, common to all bidders. Prior to bidding, the bidders receive private signals of information on the (common) value. The value and the signals are drawn from a known discrete affiliated joint distribution. The relevant task for the paper is to compare the equilibrium strategies and the seller’s revenue of three auction formats. We find that, of the three auctionformats below with two players, the discriminatory auction always gives the largest revenue to the seller; both the uniform and the Vickrey auction have zero revenue equilibrium strategies that put them further down in the revenue ranking. In equilibrium, bidders bid the same amount on both items in the discriminatory auction; a phenomenon not noted in either of the other auction formats.

  • 10.
    Ahlberg, Joakim
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics, TEK.
    Energimätning på tåg för rundvirkestransporter på sträckan Mora–Borlänge–Gävle2014Report (Other academic)
    Abstract [en]

    The third sub-project of ELVIS demonstration project for longer and heavier freight trains aims to analyze and measure energy usage of heavier trains. With heavier refers to a higher overall weight by more wagons, both loaded and unloaded, than would normally run on the route. The assumption is that heavier trains are able to do (freight) transport more energy efficient. The goal is to primarily test the hypothesis: · That energy consumption per ton can be reduced by using heavier trains. The report also illustrates the difficulties of using existing data for the evaluation of energy consumption on trains. The data in these has not been quality assured for the purposes of this study, which has caused a lot of errors and the credibility of some results are lower than otherwise would be needed. Thus, a conclusion from the project is that it would take a review of the databases of the Swedish Transport Administration on energy use should be studied further, at least if equipment such as their energy meter should be used. Alternatively, mount external equipment on locomotives to thereby generate more useful data; the latter, however, was not possible due to the owner of the locomotive. Given all sources of error associated with the data, the report analyze how the energy of a freight train is due to the gross weight of the train, the number of stops the train makes and drivers' driving style. Findings were that driving style plays a major role, between drivers the different in net energy used is up to 20 percent. Furthermore, there is differences in energy consumption connected to gross weights on the train, but then it's a bit unclear how the results should be interpreted in conjunction with the lack of quality of the data, it takes more measurements to be able to say anything definite. The same applies to the number of stops affecting the use of energy. On the first leg the number of stops had no impact on energy consumption, which it had on the investigation route.

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  • 11.
    Ahlberg, Joakim
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics, TEK.
    Intermodala transporter: definition, aktörer och omfattning2016Report (Other academic)
    Abstract [en]

    Intermodal and combined transport is often used synonymously today. The concept of combined transport has been around much longer and referred to as transportation where railway and a truck are being combined. Nowadays a combined transport often means that the goods either go by rail, inland waterways or sea and by road, or between two transport modes where trucks are not included. Intermodal and combined transport is often used synonymously today. The concept of combined transport has been around much longer and referred to as transportation where railway and a truck are being combined.

    Nowadays a combined transport often means that the goods either go by rail, inland waterways or sea and by road, or between two transport modes where trucks are not included. The EU’s so-called combi directive defines both in the same way and one of the EU Commission’s proposal to amend this directive is that EU should be considered to replace the concept of combined transport with intermodal transport. An intermodal transport precedes by a transportation decision, and this decision is often linked to a specific train path (tågläge in Swedish). If there is shortage of capacity on the track, the goods may have difficulties to be transported by train. This could potentially mean that some (rail) business / transports will not take place and the goods go by road instead.

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  • 12.
    Ahlberg, Joakim
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics, TEK.
    Kostnader för störningar i infrastrukturen: metodik och fallstudier på väg och järnväg2015Report (Other academic)
    Abstract [en]

    The purpose of this study is to illustrate the methodology that can be used in calculations of the cost to society when disruptions in the infrastructure occurs, specifically for traffic on road and rail. The principles and values that are recommended to be used in social cost-benefit analyses (CBA) in the Swedish transport sector are proposed by the ASEK-group (a working-group addressing issues on the application of CBA in the transport sector), and decided by the Swedish Transport Administration. They will be taken as given on the cost side of the CBA in this study, there will not be a benefit side since the interest for this study lies expressively on the cost side. This study is thus not a normative analysis, the aim is instead to study and apply methodologies for valuing (in monetary terms) the consequences of already occurred disturbances. The various ASEK-values require information about several aspect of the trips when calculating the value of travel time and transport time, as well as when calculating the delays and the value of travel time savings in congestion. Even though the ASEK-values are recommended by the Swedish Transport Administration, they are also questioned, especially for freight transport. This is also addressed in the report.

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  • 13.
    Ahlberg, Joakim
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics, TEK.
    Luftfartens samhällsekonomiska marginalkostnader: delstudie inom SAMKOST2014Report (Other academic)
    Abstract [en]

    This report is a literature review on the marginal social costs of aviation, and is a sub-project to VTI’s project about updating the knowledge of the external costs of traffic (SAMKOST). The report discusses which impacts of aviation are external, and which are already internalized. It is not entirely clear which impacts that should be considered as the relevant marginal costs for aviation. For example, both congestion and accidents are seen as internalized since they are already taken care of through the air traffic control service, a service that all aircraft must use in Swedish airspace by law. Similar arguments applies to the infrastructure. The large external effect is aviation’s environmental impact. It is separated into three different categories; the impact of noise, air quality and the impact on the climate.

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  • 14.
    Ahlberg, Joakim
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics Stockholm. Örebro universitet, Handelshögskolan vid Örebro Universitet.
    Multi-unit common value auctions: a laboratory experiment with three sealed-bid mechanisms2012Manuscript (preprint) (Other academic)
    Abstract [en]

    This study addresses a discrete common value environment with independent (one-dimensional) private signals, where the seller offers two identical units and the buyers have (flat) demand for both. Each session is conducted with2, 3 or 4 buyers. Three auction formats are used: the discriminatory, uniformand Vickrey auctions which are all subjected to a variation in the number of bidders and to repeating bid rounds on each subject. The main findings are that there are no significant differences between the uniform and the discriminatory auction in collecting revenue, while the Vickrey auction comes out as inferior. More bidders in the auction result in a greater revenue and level out the performance across the mechanisms. Demand reduction is visible in the experiment, but it is not as prominent as anticipated. Moreover, subjects come closer to equilibrium play over time. Finally, the winner’s curse is less severe than what is reported for inexperienced bidders in other studies.

  • 15.
    Ahlberg, Joakim
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics Stockholm. Örebro universitet, Handelshögskolan vid Örebro Universitet.
    Multi-unit common value auctions: an experimental comparison between the static and the dynamic uniform auction2012Manuscript (preprint) (Other academic)
    Abstract [en]

    It is still an open question whether the dynamic or the static format should be used in multi-unit settings, in a uniform price auction. The present study conducts an economic experiment in a common value environment, where it is found that it is more a question of whether the auctioneer wants to facilitate price discovery, and thereby lessen the otherwise pervasive overbidding, or if only the revenue is important. The experiment in the present paper provides evidence that the static format gives a significantly greater revenue than the dynamic auction, in both small and large group sizes. But a higher revenue comes at a cost; half of the auctions in the static format yield negative profits to the bidders, the winner’s curse is more severely widespread in the static auction, and only a minority of the bidders use the equilibrium bidding strategy.

  • 16.
    Ahlberg, Joakim
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics Stockholm. Örebro universitet, Handelshögskolan vid Örebro Universitet.
    Multi-unit common value auctions: theory and experiments2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Research on auctions that involve more than one identical item for sale was,almost non-existing in the 90’s, but has since then been getting increasing attention. External incentives for this research have come from the US spectrum, sales, the European 3G mobile-phone auctions,  and Internet auctions. The policy relevance and the huge amount of money involved in many of them have helped the theory and experimental research advance. But in auctions where values are equal across bidders, common value auctions, that is, when the value depends on some outside parameter, equal to all bidders, the research is still embryonic.

    This thesis contributes to the topic with three studies. The first uses a Bayesian game to model a simple multi-unit common value auction, the task being to compare equilibrium strategies and the seller’s revenue from three auction formats; the discriminatory, the uniform and the Vickrey auction. The second study conducts an economic laboratory experiment on basis of the first study. The third study comprises an experiment on the multi-unit common value uniform auction and compares the dynamic and the static environments of this format.

    The most salient result in both experiments is that subjects overbid. They are victims of the winner’s curse and bid above the expected value, thus earning a negative profit. There is some learning, but most bidders continue to earn a negative profit also in later rounds. The competitive effect when participating in an auction seems to be stronger than the rationality concerns. In the first experiment, subjects in the Vickrey auction do somewhat better in small groups than subjects in the other auction types and, in the second experiment, subjects in the dynamic auction format perform much better than subjects in the static auction format; but still, they overbid.

    Due to this overbidding, the theoretical (but not the behavioral) prediction that the dynamic auction should render more revenue than the static fails inthe second experiment. Nonetheless, the higher revenue of the static auction comes at a cost; half of the auctions yield negative profits to the bidders, and the winner’s curse is more severely widespread in this format. Besides, only a minority of the bidders use the equilibrium bidding strategy.The bottom line is that the choice between the open and sealed-bid formats may be more important than the choice of price mechanism, especially in common value settings.

    List of papers
    1. Analysis of discrete multi-unit, common value auctions: a study of three sealed-bid mechanisms
    Open this publication in new window or tab >>Analysis of discrete multi-unit, common value auctions: a study of three sealed-bid mechanisms
    2012 (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    This paper proposes a discrete bidding model for both quantities and pricing. It has a two-unit demand environment where subjects bid for contracts with an unknown redemption value, common to all bidders. Prior to bidding, the bidders receive private signals of information on the (common) value. The value and the signals are drawn from a known discrete affiliated joint distribution. The relevant task for the paper is to compare the equilibrium strategies and the seller’s revenue of three auction formats. We find that, of the three auctionformats below with two players, the discriminatory auction always gives the largest revenue to the seller; both the uniform and the Vickrey auction have zero revenue equilibrium strategies that put them further down in the revenue ranking. In equilibrium, bidders bid the same amount on both items in the discriminatory auction; a phenomenon not noted in either of the other auction formats.

    Publisher
    p. 27
    Keywords
    Economics
    National Category
    Economics
    Research subject
    SAB, Qa Economics and finance
    Identifiers
    urn:nbn:se:vti:diva-5313 (URN)
    Available from: 2013-12-03 Created: 2013-12-03 Last updated: 2016-02-04Bibliographically approved
    2. Multi-unit common value auctions: a laboratory experiment with three sealed-bid mechanisms
    Open this publication in new window or tab >>Multi-unit common value auctions: a laboratory experiment with three sealed-bid mechanisms
    2012 (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    This study addresses a discrete common value environment with independent (one-dimensional) private signals, where the seller offers two identical units and the buyers have (flat) demand for both. Each session is conducted with2, 3 or 4 buyers. Three auction formats are used: the discriminatory, uniformand Vickrey auctions which are all subjected to a variation in the number of bidders and to repeating bid rounds on each subject. The main findings are that there are no significant differences between the uniform and the discriminatory auction in collecting revenue, while the Vickrey auction comes out as inferior. More bidders in the auction result in a greater revenue and level out the performance across the mechanisms. Demand reduction is visible in the experiment, but it is not as prominent as anticipated. Moreover, subjects come closer to equilibrium play over time. Finally, the winner’s curse is less severe than what is reported for inexperienced bidders in other studies.

    Publisher
    p. 35
    Keywords
    Economics, Ekonomi
    National Category
    Economics
    Research subject
    SAB, Qa Economics and finance
    Identifiers
    urn:nbn:se:vti:diva-5314 (URN)
    Available from: 2013-12-03 Created: 2013-12-03 Last updated: 2014-06-10Bibliographically approved
    3. Multi-unit common value auctions: an experimental comparison between the static and the dynamic uniform auction
    Open this publication in new window or tab >>Multi-unit common value auctions: an experimental comparison between the static and the dynamic uniform auction
    2012 (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    It is still an open question whether the dynamic or the static format should be used in multi-unit settings, in a uniform price auction. The present study conducts an economic experiment in a common value environment, where it is found that it is more a question of whether the auctioneer wants to facilitate price discovery, and thereby lessen the otherwise pervasive overbidding, or if only the revenue is important. The experiment in the present paper provides evidence that the static format gives a significantly greater revenue than the dynamic auction, in both small and large group sizes. But a higher revenue comes at a cost; half of the auctions in the static format yield negative profits to the bidders, the winner’s curse is more severely widespread in the static auction, and only a minority of the bidders use the equilibrium bidding strategy.

    Publisher
    p. 35
    Keywords
    Economics, Ekonomi
    National Category
    Economics
    Research subject
    SAB, Qa Economics and finance
    Identifiers
    urn:nbn:se:vti:diva-5315 (URN)
    Available from: 2013-12-03 Created: 2013-12-03 Last updated: 2014-06-10Bibliographically approved
    Download full text (pdf)
    FULLTEXT01
  • 17.
    Ahlberg, Joakim
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics Stockholm.
    Optimal taxation of intermediate goods in the presence of externalities: A survey towards the transport sector2004Report (Other academic)
    Abstract [sv]

    The paper surveys the literature on optimal taxation with emphasis on intermediate goods, or, more specific, freight (road) transport. There are two models frequently used, first, the one emanated from Diamond & Mirrlees' (1971) paper, where the production efficiency lemma made it clear that intermediate goods was not to be taxed. And, second, the Ramsey-Boiteux model where a cost-of-service regulation imposes a budget constraint for the regulated firm. In the latter model, in contrast to the first, freight transports (intermediate goods) are to be taxed in the Ramsey tradition, and thus trades the production efficiency lemma against a budget restriction. The paper also discusses welfare effects due to environmental tax reforms, with emphasis to what has become to known as the double dividend hypothesis. Finally, administrative costs in the context of optimal taxation is touched upon, a subject that is to a large degree repressed in optimal tax theory.

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    FULLTEXT01
  • 18.
    Ahlberg, Joakim
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics Stockholm.
    Optimal taxation of intermediate goods in the presence of externalities: A survey towards the transport sector2006Report (Other (popular science, discussion, etc.))
    Abstract [en]

    The paper surveys the literature on optimal taxation with emphasis on intermediate goods, or, more specific, freight (road) transport. There are two models frequently used, first, the one emanated from Diamond & Mirrlees' (1971) paper, where the production efficiency lemma made it clear that intermediate goods was not to be taxed. And, second, the Ramsey-Boiteux model where a cost-of-service regulation imposes a budget constraint for the regulated firm. In the latter model, in contrast to the first, freight transports (intermediate goods) are to be taxed in the Ramsey tradition, and thus trades the production efficiency lemma against a budget restriction. The paper also discusses welfare effects due to environmental tax reforms, with emphasis to what has become to known as the double dividend hypothesis. Finally, administrative costs in the context of optimal taxation is touched upon, a subject that is to a large degree repressed in optimal tax theory.

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    fulltext
  • 19.
    Ahlberg, Joakim
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics Stockholm.
    Revenues in discrete multi-unit, common value auctions: a study of three sealed-bid mechanisms2009In: Portuguese economic journal, ISSN 1617-9838, Vol. 8, no 1, p. 21p. 3-14Article in journal (Refereed)
    Abstract [en]

    We propose in this paper a discrete bidding model, both on quantities and in pricing. It has a two-unit demand environment where subjects bid for contracts with an unknown redemption value, common to all bidders. Prior to bidding, the bidders receive private signals of information on the (common) value. Both the value and the signals are drawn from a known discrete affiliated joint distribution. The relevant task for the paper is to compare equilibrium strategies and the seller's revenue between the three auction formats. We find that, among the three auction formats below with two players, the Vickrey auction always gives the most revenue to the seller, where the discriminatory auction becomes second and the uniform auction last. We also find that, in equilibrium, bidders bid the same amount on both items in the discriminatory auction; a phenomenon we do not notice in either of the other two auction formats. There, different amount of demand reduction is encountered.

  • 20.
    Ahlberg, Joakim
    et al.
    Ramböll .
    Ericson, Johan
    WSP.
    Johansson, Oskar
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics.
    Ridderstedt, Ivan
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics.
    Marginalkostnad för luftfartens infrastruktur2017Report (Other academic)
    Abstract [en]

    The main purpose of this study is to estimate the marginal costs of aviation infrastructure. But since it not exist a uniform definition of what is the cost base of the aviation infrastructure, there is also a discussion of what costs should be included. An additional purpose of the study is to relate the estimated marginal costs to today's pricing and to investigate whether aviation pays its socio-economic costs.

    Estimates of the marginal cost of utilizing (relevant) airport infrastructure and for operating airline infrastructure is being analyzed using cost data from Stockholm Arlanda Airport and the Civil Aviation Authority. The empirical approach used to analyze cost items is a regression analysis, with adjustments for month-specific variations in travel patterns, when the airport section is investigated, and taking into account regional differences for airports when investigating air traffic control in the towers.

    There are some uncertainties in the study, but in the light of this, the results indicate that the average marginal cost of the infrastructure is around SEK 13 per passenger and SEK1,168 per aircraft started. Corresponding estimation for air traffic management is also uncertain, with results indicating a marginal cost of SEK 373 per flight. Furthermore, it appears that the revenue from marginal cost-based charges could not alone finance the state aviation infrastructure.

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  • 21.
    Ahlberg, Joakim
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics Stockholm.
    Johansson, Anna
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics Stockholm.
    Etablering av konkurrerande snabbtågstrafik på Västra stambanan: översyn ur marknadens synvinkel2014Report (Other academic)
    Abstract [en]

    As of October 2010 the railway market is liberalised. As a result, other operators than SJ could apply for track capacity also for long-distance passenger services, and the timetable for 2012 was the first timetable that was affected by the liberalisation. The Swedish railway network has, by definition, capacity restrains. The Swedish Transport Administration (Trafikverket) allocates capacity among those railway traffic operators that has applied for track capacity in the annual capacity allocation process. In the capacity allocation process for the 2014 timetable, four operators applied for capacity for long-distance high-speed train traffic between Gothenburg and Stockholm. In several cases the operators applied for the same train paths, which put Trafikverket’s applying of the process, the use of coordination and prioritization criteria, to the test for the first time since the liberalisation. VTI has interviewed the three largest of the above operators to receive information about how they experienced the capacity allocation process leading to the timetable for 2014 and to get their views on the possible obstacles that may exist for establishing a new operator on the railway market. The study was commissioned by the Swedish Transport Agency as a basis for their market surveillance in the area. The operators that are challenging SJ perceive that the capacity allocation process does not meet the requirement for competitive neutrality and non-discrimination. Both operators see the need for a more transparent process, with priority criteria that provide a more predictable outcome and which is carried out by the help of computerized tools so that the process can be implemented more efficiently and provide a more effective outcome. They argue that the construction of a timetable is so complex that it is difficult to, as now being done, manually make the most effective adjustments in the timetable necessary due to competing applications. The challenging operators therefore call for a review of the process to assess in which areas it can be improved.

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    fulltext
  • 22.
    Ahlberg, Joakim
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics, TEK.
    Nilsson, Jan-Eric
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics, TEK.
    Ad hoc-processen: hur används ledig kapacitet i järnvägsnätet?2016Report (Other academic)
    Abstract [en]

    After the Swedish Transport Administration’s adoption of next year's timetable in mid-fall each year, starts the so-called ad hoc process, i.e. requests for train paths that can use spare capacity in the network. VTI received in September 2015 Transport Agency's mission to deepen the understanding of the ad hoc-process, This “notat” reports that assignment. In light of the description that was made, the intention was to also find the measure of the importance of this process in relation to the process leading to adopting a final schedule. It has been found that the Transport Administration’s various information management systems are not designed to enable such a description.

    Thanks to a recent statistical tool, it is possible to observe that nearly 97 percent of the passenger trains booked into the annual timetable process, also actually run. This refers to two thirds of the timetable year 2015. The aim of the Transport Agency/Traffic analysis is to, in the near future, also report similar information about freight train. Behind this figure conceals both an outflow and an inflow of traffic that will be conducted in accordance with the timetable set out in the autumn of each year. However, there is no knowledge of when these changes are implemented, which is of great importance for assessing the degree of flexibility in the ad hoc process. This situation may change as a result of the Transport Agency as of the timetable relating to 2016 for the charges to cancel the allocated capacity. The fee will be higher the closer to the scheduled departure of the train the application is withdrawn. This can help improve the flexibility in the use of the track capacity not reserved in the annual timetabling process. Another consequence may be that the information on the process will improve.

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  • 23.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Fors, Carina
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Forward, Sonja
    Swedish National Road and Transport Research Institute, Society, environment and transport, Mobility, actors and planning processes.
    Gregersen, Nils Petter
    Swedish National Road and Transport Research Institute, Society, environment and transport, Mobility, actors and planning processes.
    Hjälmdahl, Magnus
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Jansson, Jonas
    Swedish National Road and Transport Research Institute, Traffic and road users.
    Kircher, Katja
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Lindberg, Gunnar
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics Stockholm.
    Nilsson, Lena
    Swedish National Road and Transport Research Institute, Traffic and road users.
    Patten, Christopher
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Dangerous use of mobile phones and other communication devices while driving: A toolbox of counter-measures2013In: Proceedings of the 16th International Conference Road Safety on Four Continents: Beijing, China. 15-17 May 2013, Linköping: Statens väg- och transportforskningsinstitut, 2013Conference paper (Other academic)
    Abstract [en]

    The use of mobile phone and similar devices while driving has been a topic of discussion and research for several years. It is now an established fact that driving performance is deteriorated due to distraction but no clear conclusions can yet be drawn concerning influence on crash rates. Better studies on this relationship is needed. Most countries in Europe and many countries elsewhere have introduced different types of bans for handheld devices. Sweden has, however, no such bans. VTI was commissioned by the Swedish Government to outline possible means to reduce the dangerous usage of mobile phones and other communication devices while driving as alternatives to banning. This task was a result of a previous VTI-state-of-the-art review of research on mobile phone and other communication device usage while driving. One of the findings in the review was that bans on handheld phones did not appear to reduce the number of crashes.

    Eighteen different countermeasures in three main areas were suggested. (1) Technical solutions such as countermeasures directed towards the infrastructure, the vehicle and the communication device. (2) Education and information, describing different ways to increase knowledge and understanding among stakeholders and different driver categories. (3) Different possibilities for how society, industry and organisations can influence the behaviour of individuals, via policies, rules, recommendations and incentives. Our conclusion is that a combination of different countermeasures is needed – where education and information to the drivers are combined with support and incentives for a safe usage of different communication devices.

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  • 24.
    Ainge, Mike
    et al.
    TRL, UK.
    Altekoester, Carsten
    BASt, Germany.
    Nelson, Paul
    TRL, UK.
    Phillips, Steve
    FEHRL.
    Sandberg, Ulf
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment. Swedish National Road and Transport Research Institute, Society, environment and transport, Enviroment and traffic analysis.
    Steven, Heinz
    TÜV Nord, Germany.
    Treleven, Colin
    TRL, UK.
    Watts, Greg
    TRL, UK.
    Final report si2.408210: Tyre/road noise2007Report (Other academic)
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    Final report
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    Appendices
  • 25.
    Ait Ali, Abderrahman
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics.
    Eliasson, Jonas
    Linköping University.
    European railway deregulation: an overview of market organization and capacity allocation2021In: Transportmetrica A: Transport Science, ISSN 2324-9935, E-ISSN 2324-9943Article in journal (Refereed)
    Abstract [en]

    European railways have been reorganized to allow for market competition. Thus, train services have been vertically separated from infrastructure management which allows several operators to compete. Different ways have emerged for vertical separation, capacity allocation and track access charges. This paper reviews important deregulation aspects from a number of European countries. The study compares how competition has been introduced and regulated with focus on describing capacity allocation and track access charges. Although guided by the same European legislation, we conclude that the studied railways have different deregulation outcomes, e.g. market organization, capacity allocation. Besides, few countries have so far managed to have efficient and transparent capacity allocation. Although allowed by the legislation, market-based allocation is absent or never used. To foster more competition which can yield substantial social benefits, the survey indicates that most European railways still need to develop and experiment with more efficient and transparent capacity allocation procedures. © 2021 Vti Swedish National Road and Transport Research Institute. Published by Informa UK Limited, trading as Taylor & Francis Group.

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  • 26.
    Ait Ali, Abderrahman
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics.
    Eliasson, Jonas
    Linköpings universitet.
    Railway capacity allocation: a survey of market organizations, allocation processes and track access charges2019Report (Other academic)
    Abstract [en]

    In the last few decades, many railway markets (especially in Europe) have been restructured to allow competition between different operators. This survey studies how competition has been introduced and regulated in a number of different countries around the world. In particular, we focus on a central part of market regulation specific to railway markets, namely the capacity allocation process. Conflicting capacity requests from different train operators need to be regulated and resolved, and the efficiency and transparency of this process is crucial. Related to this issue is how access charges are constructed and applied. Several European countries have vertically separated their railway markets, separating infrastructure management from train services provisions, thus allowing several train operators to compete with different passengers and freight services. However, few countries have so far managed to create efficient and transparent processes for allocating capacity between competing train operators, and incumbent operators still have larger market-share in many markets.

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  • 27.
    Ait Ali, Abderrahman
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics.
    Eliasson, Jonas
    Linköping University, Sweden.
    The value of additional data for public transport origin: destination matrix estimation2021In: Public Transport, ISSN 1866-749X, E-ISSN 1613-7159Article in journal (Refereed)
    Abstract [en]

    Passenger origin–destination data is an important input for public transport planning. In recent years, new data sources have become increasingly common through the use of the automatic collection of entry counts, exit counts and link flows. However, collecting such data can be sometimes costly. The value of additional data collection hence has to be weighed against its costs. We study the value of additional data for estimating time-dependent origin–destination matrices, using a case study from the London Piccadilly underground line. Our focus is on how the precision of the estimated matrix increases when additional data on link flow, destination count and/or average travel distance is added, starting from origin counts only. We concentrate on the precision of the most policy-relevant estimation outputs, namely, link flows and station exit flows. Our results suggest that link flows are harder to estimate than exit flows, and only using entry and exit data is far from enough to estimate link flows with any precision. Information about the average trip distance adds greatly to the estimation precision. The marginal value of additional destination counts decreases only slowly, so a relatively large number of exit station measurement points seem warranted. Link flow data for a subset of links hardly add to the precision, especially if other data have already been added. © 2021, The Author(s).

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  • 28.
    Ait Ali, Abderrahman
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics.
    Eliasson, Jonas
    Linköping Universit, Sweden; Swedish Transport Administration, Sweden.
    Warg, J.
    Royal Institute of Technology, Sweden.
    Are commuter train timetables consistent with passengers’ valuations of waiting times and in-vehicle crowding?2022In: Transport Policy, ISSN 0967-070X, E-ISSN 1879-310X, Vol. 116, p. 188-198Article in journal (Refereed)
    Abstract [en]

    Social cost-benefit analysis is often used to analyse transport investments, and can also be used for transport operation planning and capacity allocation. If it is to be used for resolving capacity conflicts, however, it is important to know whether transit agencies' timetable requests are consistent with the cost-benefit framework, which is based on passenger preferences. We show how a public transport agency's implicit valuations of waiting time and crowding can be estimated by analysing timetables, apply the method to commuter train timetables in Stockholm, and compare the implicit valuations to the corresponding passenger valuations in the official Swedish cost-benefit analysis guidelines. The results suggest that the agency puts a slightly lower value on waiting time and crowding than the passenger valuations codified in the official guidelines. We discuss possible reasons for this and implications for using cost-benefit analysis for capacity allocation. We also find that optimal frequencies are more sensitive to the waiting time valuation than to that of crowding. © 2021 The Authors

  • 29.
    Ait Ali, Abderrahman
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics.
    Eliasson, Jonas
    Linköpings universitet.
    Warg, Jennifer
    KTH.
    Are commuter train timetables consistent with passengers’ valuations of waiting times and in-vehicle crowding?2020Report (Other academic)
    Abstract [en]

    Many models have been developed and used to analyse the costs and benefits of transport investments. Similar tools can also be used for transport operation planning and capacity allocation. An example of such use is the assessment of commuter train operations and service frequency. In this study, we analyse the societally optimal frequency for commuter train services. The aim is to reveal the implicit valuation (by the public transport agency) of the waiting time and the in-vehicle crowding in the commuting system. We use an analytic CBA model to formulate the societal costs of a certain service frequency and analyse the societally optimal frequencies during peak and off-peak hours. Comparing the optimal and the actual frequencies allows to reveal the implicit valuations of waiting time and crowding. Using relevant data from the commuter train services in Stockholm on a typical working day in September 2015 (e.g., OD matrix, cost parameters), we perform a numerical analysis on certain lines and directions. We find the societally optimal frequency and the implicit valuation of waiting time and crowding. The results suggest that the public transport agency in Stockholm (i.e., SL) adopted service frequencies that are generally slightly higher than societally optimum which can be explained by a higher implicit valuation of waiting time and crowding. We also find that the optimal frequencies are more sensitive to the waiting time valuation rather than that of crowding.

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  • 30.
    Ait Ali, Abderrahman
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics.
    Kurt, Filiz
    Deutsches Zentrum für Luft- und Raumfahrt (DLR).
    Isberner, Alessa
    Deutsches Zentrum für Luft- und Raumfahrt (DLR).
    Odolinski, Kristofer
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics.
    Berg, Mats
    KTH.
    Assessing innovations in High-Speed Rail infrastructure2023Report (Other academic)
    Abstract [en]

    Innovations in high-speed rail (HSR) have had substantial effects on different stakeholders within and outside the railway system. As part of the European Shift2Rail research programme, several innovative solutions are developed for, among others, improving the HSR infrastructure. The joint undertaking behind this research program has set objectives for these innovations in terms of punctuality, capacity, and life cycle costs. With a focus on infrastructure-related innovations for HSR, this paper aims at assessing their impacts in relation to these targets. We review the relevant research literature about the effects of HSR innovations and their assessment. The paper presents a hybrid assessment methodology combing different approaches to assess capacity, punctuality, and cost effects. This contributes to reducing the existing gap that is found in the research literature. Based on a reference scenario for HSR line and collected data from different stakeholders, the results indicate that infrastructure innovations in HSR, being developed within the European Shift2Rail research programme, can contribute to reaching the target set for punctuality. Further innovations in HSR infrastructure and/or other railway assets may be needed to reach additional targets and for more accurate improvement values giving more insights into their impacts.

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  • 31.
    Ait Ali, Abderrahman
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics.
    Kurt, Filiz
    Deutsches Zentrum für Luft-und Raumfahrt, Germany.
    Isberner, Alessa
    Deutsches Zentrum für Luft-und Raumfahrt, Germany.
    Odolinski, Kristofer
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics.
    Berg, Mats
    KTH.
    Assessing Innovations in High-Speed Rail Infrastructure2023In: Socioeconomic Impacts of High-Speed Rail Systems: Proceedings of the 2nd International Workshop on High-Speed Rail Socioeconomic Impacts, University of Naples Federco II, Italy, 13–14 September 2022 / [ed] Francesca Pagliara, Springer, 2023, p. 217-233Conference paper (Refereed)
    Abstract [en]

    Innovations in high-speed rail (HSR) have had substantial effects on different stakeholders within and outside the railway system. As part of the European Shift2Rail research programme, several innovative solutions are developed for, among others, improving the HSR infrastructure. The Joint Undertaking behind this research program has set objectives for these innovations in terms of punctuality, capacity, and life cycle costs. With a focus on infrastructure-related innovations for HSR, this paper aims at assessing their impacts in relation to these targets. We review the relevant research literature about the effects of HSR innovations and their assessment. The paper presents a hybrid assessment methodology combing different approaches to assess capacity, punctuality, and cost effects. This contributes to reducing the existing gap that is found in the research literature. Based on a reference scenario for HSR line and collected data from different stakeholders, the results indicate that infrastructure innovations in HSR, being developed within the European Shift2Rail research programme, can contribute to reaching the target set for punctuality. Further innovations in HSR infrastructure and/or other railway assets may be needed to reach additional targets and for more accurate improvement values giving more insights into their impacts. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

  • 32.
    Ait Ali, Abderrahman
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics.
    Lidén, Tomas
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Minimal utilization rate for railway maintenance windows: a cost-benefit approach2022In: European Journal of Transport and Infrastructure Research, ISSN 1567-7133, E-ISSN 1567-7141, Vol. 22, no 2, p. 108-131Article in journal (Refereed)
    Abstract [en]

    Methods for economic assessment are often used in the rail sector to evaluate large infrastructure investments such as new high-speed lines. With larger networks and ageing infrastructure, these methods can also be used for planning maintenance. In this paper, we focus on the newly introduced concept of maintenance windows in Sweden. These are pre-allocated slots in the train timetable dedicated to performing, among others, periodic/frequent maintenance activities. To justify the pre-allocation of such windows, this study presents a method to find minimal utilization rates depending on window designs and traffic situations. Using a cost-benefit approach, the windows are assessed using a total social cost including work costs, loss in traffic production and reliability gains in future traffic. Based on a case study from the Southern main line in Sweden, we study the minimal utilization rate in different test scenarios, i.e., night or day shifts, asset degradation functions and designs of maintenance windows. The results show that lower utilization rates (4-42%) can be accepted during low-volume traffic or for partial closures, while higher utilization rates (47-83%) are required for full closures during high-volume traffic. Whether the rates are measured as the share of used window time or the share of utilized windows is less important, especially when higher utilization is required. Sensitivity analyses of asset knowledge indicate that parameters such as asset degradation function and minimum asset quality (and to a lesser extent traffic volume, discount rate and failure likelihood) can have a substantial effect on the minimum required utilization rates.

  • 33.
    Ait Ali, Abderrahman
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics.
    Lidén, Tomas
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Minimal utilization rates for railway maintenance windows: a cost-benefit approach2021Report (Other academic)
    Abstract [en]

    Methods for economic assessment, e.g., cost-benefit analysis, are often used in the rail sector to evaluate large infrastructure investments such as building new high-speed railway lines. With larger railway networks and aging infrastructure, these methods can also be used for maintenance planning decisions. In this paper, we focus on basic maintenance and the newly introduced concept of maintenance windows in Sweden. These are pre-allocated slots in the annual train timetable dedicated to performing, among others, periodic/frequent maintenance activities such as inspections, maintenance and repairs. To justify the pre-allocation of such windows, this study presents a method to find minimal utilization rates depending on window designs and traffic situations. Using a cost-benefit approach, the maintenance windows are assessed using a total social cost including maintenance work costs, loss in traffic production and reliability gains in future traffic. Based on a case study from the Southern main line in Sweden, we study the minimal utilization rate in different test scenarios, i.e., night or day shifts, asset degradation functions and designs of maintenance windows. The results show that lower utilization rates (5-50%) can be accepted during low-volume traffic or for partial closures, while higher utilization rates (50-90%) are required for full closures during high-volume traffic. Whether the rates are measured as share of used window time or share of utilized windows is less important, especially when higher utilization is required.

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  • 34.
    Ait Ali, Abderrahman
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics.
    Lindberg, Per Olov
    Eliasson, Jonas
    Linköping University.
    Nilsson, Jan-Eric
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics.
    Peterson, Anders
    Linköping University.
    A disaggregate bundle method for train timetabling problems2020In: Journal of Rail Transport Planning & Management, ISSN 2210-9706, E-ISSN 2210-9714, article id 100200Article in journal (Refereed)
    Abstract [en]

    The train timetabling problem (TTP) consists of finding a feasible timetable for a number of trains which minimises some objective function, e.g., sum of running times or deviations from ideal departure times. One solution approach is to solve the dual problem of the TTP using so-called bundle methods. This paper presents a new bundle method that uses disaggregate data, as opposed to the standard bundle method which in a certain sense relies on aggregate data. We compare the disaggregate and aggregate methods on realistic train timetabling scenarios from the Iron Ore line in Northern Sweden. Numerical results indicate that the proposed disaggregate method reaches better solutions faster than the standard aggregate approach. © 2020 Elsevier Ltd

  • 35.
    Ait Ali, Abderrahman
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics.
    Odolinski, Kristofer
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics.
    Pålsson, Björn
    Mechanics and Maritime Sciences/CHARMEC, Chalmers.
    Torstensson, Peter
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Evaluating the mix of maintenance activities on railway crossings with respect to life-cycle costs2023Report (Other academic)
    Abstract [en]

    Switches & crossings (S&Cs) are vital assets as they allow for increased railway capacity by introducing flexibility and connectivity in railway networks. At the same time, this makes them critical since they can cause costly delays and disruptions if they are not well maintained. This motivates studies to improve maintenance strategies of S&Cs, considering both the life-cycle costs (LCC) of the assets and socio-economic transportation costs for passengers and freight customers. In this paper, the interdependence between deterioration mechanisms, maintenance activities, and expected LCC (including transportation costs) is investigated using a combination of mechanical and econometric modelling. The interrelation between the degradation of contact geometry and track settlement is analysed using simulations of dynamic vehicle–turnout interaction. Long-term mechanical degradation of the S&C is simulated for different maintenance strategies that correspond to different timing of the associated maintenance measures (crossing repair welding and tamping). This provides the basis for analysing the interdependence between preventive and corrective activities using econometric modelling. Based on a case study of a common type of S&Cs in the Swedish infrastructure, the impact of different maintenance strategies on LCC and transportation costs is analysed. Opportunities and challenges in the development of more socio-economically effective maintenance strategies of S&Cs are discussed.

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  • 36.
    Ait Ali, Abderrahman
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics.
    Pålsson, Björn
    Chalmers University of Technology, Department of Mechanics and Maritime Sciences/CHARMEC, Sweden.
    Odolinski, Kristofer
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics.
    Torstensson, Peter
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Evaluation of long-term maintenance of switches & crossings with respect to life-cycle costs and socio-economic impact2022Conference paper (Other academic)
    Abstract [en]

    Switches & crossings (S&Cs) are vital assets as they allow for increased railway capacity by introducing flexibility and connectivity in railway networks. At the same time this makes them critical, and they can cause major delays and disruptions if they are not well maintained. This motivates studies to improve maintenance strategies of S&Cs, considering both life-cycle costs (LCC) of the assets and other additional socio-economic costs (e.g., transportation costs for passengers and freight customers). In this paper, the interdependence between deterioration mechanisms, maintenance activities, and expected LCC (including transportation costs) is investigated using a combination of mechanical and econometric modelling.

    The interrelation between the degradation of contact geometry and track settlement is analysed using simulations of dynamic vehicle–turnout interaction. Changes in the timing of the associated maintenance measures (crossing repair welding and tamping) are performed to investigate the impact on damage modes. This is then linked to LCC and transportation costs, which requires a distribution between preventive and corrective activities with respect to the simulated maintenance strategy. This relationship is investigated by means of regression modelling: 𝑪𝒐𝒓𝒓𝒆𝒄𝒕𝒊𝒗𝒆=𝑓(𝑷𝒓𝒆𝒗𝒆𝒏𝒕𝒊𝒗𝒆,𝑿)

    where Corrective and Preventive represent the number of failures and the scheduled actions to prevent these failures, respectively. 𝑿 holds variables related to the traffic (volume, type of traffic, axle load, etc.) and the infrastructure (type of S&Cs, etc.).

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  • 37.
    Ait Ali, Abderrahman
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics.
    Warg, Jennifer
    KTH.
    Eliasson, Jonas
    Linköpings universitet.
    Pricing commercial train path requests based on societal costs2019Report (Other academic)
    Abstract [en]

    On deregulated railway markets, efficient capacity allocation is important. We study the case where commercial trains and publicly controlled traffic (“commuter trains”) use the same railway infrastructure and hence compete for capacity. We develop a method that can be used by an infrastructure manager trying to allocate capacity in a socially efficient way. The method calculates the loss of social benefits incurred by changing the commuter train timetable to accommodate a commercial train path request and based on this calculates a reservation price for the train path request. If the commercial operator’s willingness-to-pay for the train path exceeds the loss of social benefits, its request is approved. The calculation of social benefits takes into account changes in commuter train passengers’ travel times, waiting times, transfers and crowding, and changes in operating costs for the commuter train operator(s). The method is implemented in a microscopic simulation program, which makes it possible to test the robustness and feasibility of timetable alternatives. We show that the method is possible to apply in practice by demonstrating it in a case study from Stockholm, illustrating the magnitudes of the resulting commercial train path prices. We conclude that marginal societal costs of railway capacity in Stockholm are considerably higher than the current track access charges.

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  • 38.
    Ait Ali, Abderrahman
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics. Linköping University.
    Warg, Jennifer
    KTH Royal Institute of Technology.
    Eliasson, Jonas
    Linköping University.
    Pricing commercial train path requests based on societal costs2020In: Transportation Research Part A: Policy and Practice, ISSN 0965-8564, E-ISSN 1879-2375, Vol. 132, p. 452-464Article in journal (Refereed)
    Abstract [en]

    On deregulated railway markets, efficient capacity allocation is important. We study the case where commercial trains and publicly controlled traffic (“commuter trains”) use the same railway infrastructure and hence compete for capacity. We develop a method that can be used by an infrastructure manager trying to allocate capacity in a socially efficient way. The method calculates the loss of societal benefits incurred by changing the commuter train timetable to accommodate a commercial train path request, and based on this calculates a reservation price for the train path request. If the commercial operator's willingness-to-pay for the train path exceeds the loss of societal benefits, its request is approved. The calculation of these benefits takes into account changes in commuter train passengers’ travel times, waiting times, transfers and crowding, and changes in operating costs for the commuter train operator(s). The method is implemented in a microscopic simulation program, which makes it possible to test the robustness and feasibility of timetable alternatives. We show that the method is possible to apply in practice by demonstrating it in a case study from Stockholm, illustrating the magnitudes of the resulting commercial train path prices. We conclude that marginal societal costs of railway capacity in Stockholm are considerably higher than the current track access charges.

  • 39.
    Alatalo, Juha M
    et al.
    Uppsala Universitet, Campus Gotland.
    Jägerbrand, Annika K
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Molau, Ulf
    Göteborg Universitet.
    Climate change and climatic events: Community-, functional- and species-level responses of bryophytes and lichens to constant, stepwise, and pulse experimental warming in an alpine tundra2014In: Alpine Botany, ISSN 1664-2201, Vol. 124, no 2, p. 81-91Article in journal (Refereed)
    Abstract [en]

    We experimentally imposed three different kinds of warming scenarios over 3 years on an alpine meadow community to identify the differential effects of climate warming and extreme climatic events on the abundance and biomass of bryophytes and lichens. Treatments consisted of (a) a constant level of warming with open top chambers (an average temperature increase of 1.87 °C), (b) a yearly stepwise increase of warming (average temperature increases of 1.0; 1.87 and 3.54 °C, consecutively), and (c) a pulse warming, i.e., a single first year pulse event of warming (average temperature increase of 3.54 °C only during the first year). To our knowledge, this is the first climate change study that attempts to distinguish between the effects of constant, stepwise and pulse warming on bryophyte and lichen communities. We hypothesised that pulse warming would have a significant short-term effect compared to the other warming treatments, and that stepwise warming would have a significant mid-term effect compared to the other warming treatments. Acrocarpous bryophytes as a group increased in abundance and biomass to the short-term effect of pulse warming. We found no significant effects of mid-term (third-year) stepwise warming. However, one pleurocarpous bryophyte species, Tomentypnum nitens, generally increased in abundance during the warm year 1997 but decreased in control plots and in response to the stepwise warming treatment. Three years of experimental warming (all treatments as a group) did have a significant impact at the community level, yet changes in abundance did not translate into significant changes in the dominance hierarchies at the functional level (for acrocarpous bryophytes, pleurocarpous bryophytes, Sphagnum or lichens), or in significant changes in other bryophyte or lichen species. The results suggest that bryophytes and lichens, both at the functional group and species level, to a large extent are resistant to the different climate change warming simulations that were applied.

  • 40.
    Alatalo, Juha M
    et al.
    Qatar University.
    Jägerbrand, Annika K
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Molau, Ulf
    Göteborgs Universitet.
    Impacts of different climate change regimes and extreme climatic events on an alpine meadow community2016In: Scientific Reports, E-ISSN 2045-2322, Vol. 6, article id 21720Article in journal (Refereed)
    Abstract [en]

    Climate variability is expected to increase in future but there exist very few experimental studies that apply different warming regimes on plant communities over several years. We studied an alpine meadow community under three warming regimes over three years. Treatments consisted of (a) a constant level of warming with open-top chambers (ca. 1.9 °C above ambient), (b) yearly stepwise increases in warming (increases of ca. 1.0, 1.9 and 3.5 °C), and (c) pulse warming, a single first-year pulse event of warming (increase of ca. 3.5 °C). Pulse warming and stepwise warming was hypothesised to cause distinct first-year and third-year effects, respectively. We found support for both hypotheses; however, the responses varied among measurement levels (whole community, canopy, bottom layer, and plant functional groups), treatments, and time. Our study revealed complex responses of the alpine plant community to the different experimentally imposed climate warming regimes. Plant cover, height and biomass frequently responded distinctly to the constant level of warming, the stepwise increase in warming and the extreme pulse-warming event. Notably, we found that stepwise warming had an accumulating effect on biomass, the responses to the different warming regimes varied among functional groups, and the short-term perturbations had negative effect on species richness and diversity.

  • 41.
    Alatalo, Juha M.
    et al.
    Uppsala Universitet.
    Jägerbrand, Annika
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Molau, Ulf
    University of Gothenburg.
    Seven years of experimental warming and nutrient addition causes decline of bryophytes and lichens in alpine meadow and heath communitiesManuscript (preprint) (Other academic)
    Abstract [sv]

    Global change is predicted to have large and rapid impact on polar and alpine regions. Bryophytes and lichens increase their importance in terms of biomass, carbon/nutrient cycling, cover and ecosystem functioning at higher latitudes/altitudes. Here we report from a seven year factorial experiment with nutrient addition and warming on the abundance of bryophytes and lichens in an alpine meadow and heath community. Treatments had significant negative effect on relative change of total abundance bryophytes and lichens, the largest decline to the nutrient addition and the combined nutrient addition and warming treatments, bryophytes decreasing most in the meadow, lichens most in the heath. Nutrient addition, and the combined nutrient addition and warming brought rapid decrease in both bryophytes and lichens, while warming had a delayed negative impact. Of sixteen species that were included the statistical analyses, we found significant negative effects on seven species. We show that impact of simulated global change on bryophytes and lichens differ in in time and magnitude among treatments and plant communities. Our results underscore the importance of longer-term studies to improve the quality of climate change models, as short-term studies are poor predictors of longer-term responses of bryophytes and lichens, similar to what have been shown for vascular plants. Species-specific responses may differ in time, and this will likely cause changes in the dominance structures of bryophytes and lichens over time.

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  • 42.
    Alatalo, Juha, M.
    et al.
    Uppsala Universitet.
    Jägerbrand, Annika
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Molau, Ulf
    Göteborgs Universitet.
    Testing reliability of short-term responses to predict longer-term responses of bryophytes and lichens to environmental change2015In: Ecological Indicators, ISSN 1470-160X, E-ISSN 1872-7034, Vol. 58, p. 77-85Article in journal (Refereed)
    Abstract [en]

    Environmental changes are predicted to have severe and rapid impacts on polar and alpine regions. At high latitudes/altitudes, cryptogams such as bryophytes and lichens are of great importance in terms of biomass, carbon/nutrient cycling, cover and ecosystem functioning. This seven-year factorial experiment examined the effects of fertilizing and experimental warming on bryophyte and lichen abundance in an alpine meadow and a heath community in subarctic Sweden. The aim was to determine whether short-term responses (five years) are good predictors of longer-term responses (seven years). Fertilizing and warming had significant negative effects on total and relative abundance of bryophytes and lichens, with the largest and most rapid decline caused by fertilizing and combined fertilizing and warming. Bryophytes decreased most in the alpine meadow community, which was bryophyte-dominated, and lichens decreased most in the heath community, which was lichen-dominated. This was surprising, as the most diverse group in each community was expected to be most resistant to perturbation. Warming alone had a delayed negative impact. Of the 16 species included in statistical analyses, seven were significantly negatively affected. Overall, the impacts of simulated warming on bryophytes and lichens as a whole and on individual species differed in time and magnitude between treatments and plant communities (meadow and heath). This will likely cause changes in the dominance structures over time. These results underscore the importance of longer-term studies to improve the quality of data used in climate change models, as models based on short-term data are poor predictors of long-term responses of bryophytes and lichens.

  • 43.
    Alatalo, Juha M
    et al.
    Qatar University.
    Jägerbrand, Annika
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Čuchta, Peter
    Academy of Science of the Czech Republic.
    Collembola at three alpine subarctic sites resistant to twenty years of experimental warming2015In: Scientific Reports, E-ISSN 2045-2322, Vol. 5, article id 18161Article in journal (Refereed)
    Abstract [en]

    This study examined the effects of micro-scale, site and 19 and 21 years of experimental warming on Collembola in three contrasting alpine subarctic plant communities (poor heath, rich meadow, wet meadow). Unexpectedly, experimental long-term warming had no significant effect on species richness, effective number of species, total abundance or abundance of any Collembola species. There were micro-scale effects on species richness, total abundance, and abundance of 10 of 35 species identified. Site had significant effect on effective number of species, and abundance of six species, with abundance patterns differing between sites. Site and long-term warming gave non-significant trends in species richness.

    The highest species richness was observed in poor heath, but mean species richness tended to be highest in rich meadow and lowest in wet meadow. Warming showed a tendency for a negative impact on species richness. This long-term warming experiment across three contrasting sites revealed that Collembola is capable of high resistance to climate change. We demonstrated that micro-scale and site effects are the main controlling factors for Collembola abundance in high alpine subarctic environments. Thus local heterogeneity is likely important for soil fauna composition and may play a crucial role in buffering Collembola against future climate change.

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  • 44.
    Alatalo, Juha M.
    et al.
    Department of Ecology and Genetics, Uppsala University, Visby, Sweden.
    Little, Chelsea, J.
    Department of Ecology and Genetics, Uppsala University, Visby, Sweden.
    Jägerbrand, Annika
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Molau, Ulf
    Göteborgs Universitet.
    Dominance hierarchies, diversity and species richness of vascular plants in an alpine meadow: contrasting short and medium term responses to simulated global change2014In: PeerJ, E-ISSN 2167-8359, Vol. 2, article id e406Article in journal (Refereed)
    Abstract [en]

    We studied the impact of simulated global change on a high alpine meadow plant community. Specifically, we examined whether short-term (5 years) responses are good predictors for medium-term (7 years) changes in the system by applying a factorial warming and nutrient manipulation to 20 plots in Latnjajaure, subarctic Sweden. Seven years of experimental warming and nutrient enhancement caused dramatic shifts in dominance hierarchies in response to the nutrient and the combined warming and nutrient enhancement treatments. Dominance hierarchies in the meadow moved from a community being dominated by cushion plants, deciduous, and evergreen shrubs to a community being dominated by grasses, sedges, and forbs. Short-term responses were shown to be inconsistent in their ability to predict medium-term responses for most functional groups, however, grasses showed a consistent and very substantial increase in response to nutrient addition over the seven years.

    The non-linear responses over time point out the importance of longer-term studies with repeated measurements to be able to better predict future changes. Forecasted changes to temperature and nutrient availability have implications for trophic interactions, and may ultimately influence the access to and palatability of the forage for grazers. Depending on what anthropogenic change will be most pronounced in the future (increase in nutrient deposits, warming, or a combination of them both), different shifts in community dominance hierarchies may occur. Generally, this study supports the productivity–diversity relationship found across arctic habitats, with community diversity peaking in mid-productivity systems and degrading as nutrient availability increases further. This is likely due the increasing competition in plant–plant interactions and the shifting dominance structure with grasses taking over the experimental plots, suggesting that global change could have high costs to biodiversity in the Arctic.

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  • 45.
    Alatalo, Juha, M.
    et al.
    Uppsala Universitet.
    Little, Chelsea, J.
    Uppsala Universitet.
    Jägerbrand, Annika
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Molau, Ulf
    Göteborgs Universitet.
    Vascular plant abundance and diversity in an alpine heath under observed and simulated global change2015In: Scientific Reports, E-ISSN 2045-2322, Vol. 5, p. 1-11, article id 10197Article in journal (Refereed)
    Abstract [en]

    Global change is predicted to cause shifts in species distributions and biodiversity in arctic tundra. We applied factorial warming and nutrient manipulation to a nutrient and species poor alpine/arctic heath community for seven years. Vascular plant abundance in control plots increased by 31%. There were also notable changes in cover in the nutrient and combined nutrient and warming treatments, with deciduous and evergreen shrubs declining, grasses overgrowing these plots. Sedge abundance initially increased significantly with nutrient amendment and then declined, going below initial values in the combined nutrient and warming treatment. Nutrient addition resulted in a change in dominance hierarchy from deciduous shrubs to grasses. We found significant declines in vascular plant diversity and evenness in the warming treatment and a decline in diversity in the combined warming and nutrient addition treatment, while nutrient addition caused a decline in species richness. The results give some experimental support that species poor plant communities with low diversity may be more vulnerable to loss of species diversity than communities with higher initial diversity. The projected increase in nutrient deposition and warming may therefore have negative impacts on ecosystem processes, functioning and services due to loss of species diversity in an already impoverished environment.

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  • 46.
    Aldenius, Malin
    et al.
    Lund University.
    Tsaxiri, Panagiota
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics. Linköping University.
    Lidestam, Helene
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics. K2.
    The role of environmental requirements in Swedish public procurement of bus transports2021In: International Journal of Sustainable Transportation, ISSN 1556-8318, E-ISSN 1556-8334, Vol. 16, no 5, p. 391-405Article in journal (Refereed)
    Abstract [en]

    The transport sector needs to become sustainable and public transport has an important role to play. Green public procurement has proven to have great potential to influence the transition to a sustainable public transport sector. Sweden is a good example of a country that uses public procurement in the public transport sector to a large extent and has at the same time come far in the transition to renewable fuel. The aim of this study is to examine what role public transport authorities (PTAs) can have in supporting more environmentally sustainable public transport through public procurement. This was done by a content analysis regarding the expressions of environmental requirements historically, over a ten-year period, in tender documents in Sweden, followed by a workshop where the implications of the findings and future tender processes were discussed with relevant actors. The results showed that all the environmental requirements have become stricter during the studied period, but indicate a tendency for higher use of environmental requirements in tendering of larger areas as well as in tendering of public transport within cities. Specifically, for requirements for fuel, the same tenders also use specific requirements to a higher extent. However, the subsequent workshop discussions indicated that the use of specific requirements is one reason for disagreement among involved actors. Overall, this study of the Swedish public transport case showed that PTAs have a large potential to support more environmentally sustainable solutions using environmental requirements in public procurement.

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  • 47.
    Alexandersson, Gunnar
    et al.
    Stockholm School of Economics Institute for Research, Sweden.
    Andersson, Matts
    WSP Advisory, Sweden.
    Bondemark, Anders
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics.
    Hulten, Staffan
    Stockholm School of Economics Institute for Research, Sweden.
    Neither market nor hierarchy: coordination costs in the allocation of track capacity in the Swedish railway network2022In: Annals of Public and Cooperative Economics, ISSN 1370-4788, E-ISSN 1467-8292Article in journal (Refereed)
    Abstract [en]

    Transaction costs have been an issue since the advent of the deregulation of the European railway markets in the 1990s. Transaction cost economics received renewed attention in research on the deregulated railway markets in the EU after the publications of two influential reports in the early 2010s. In this article, we develop a model that enables classification and measurement of transaction costs and other coordination costs in deregulated markets. This model is then used to analyze the costs of path allocation in the Swedish railway sector and to compare the results with findings in previous research. We also discuss the economic rationale of the distribution of coordination costs among the involved parties. Our key empirical findings are that the total coordination costs in the Swedish market-mimicking path allocation process are as low as or lower than the most cost-efficient market coordination processes studied in railway markets, and that the state administrations take on nearly all the coordination costs in order to minimize the effects of opportunism, rent-seeking and information impactedness. Another finding is that the size of the coordination costs found by different studies seems to be dependent on whether a bottom-up or a top-down approach is used.

  • 48.
    Alexandersson, Gunnar
    et al.
    Stockholm school of economics.
    Hultén, Staffan
    Stockholm school of economics.
    Nilsson, Jan-Eric
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics Stockholm.
    Pyddoke, Roger
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics Stockholm.
    The liberalization of railway passenger transport in Sweden: outstanding regulatory challenges2012Report (Other academic)
    Abstract [en]

    The purpose of this paper is to describe Sweden’s recent reforms to open the railway passenger markets to entry, and to addresses four critical issues for the success of the reforms; the allocation of infrastructure capacity, the provision of maintenance and terminal facilities, the access to rolling stock and the provision of information and ticketing to travelers. The analysis shows that the legislation and regulatory tools that are needed to handle these challenges to a large extent remain to be developed.

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  • 49.
    Ali, Arshad
    et al.
    East China Normal University.
    Molau, Ulf
    Göteborgs Universitet.
    Bai, Yang
    Chinese Academy of Sciences.
    Jägerbrand, Annika K
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Alatalo, Juha M.
    Qatar University.
    Diversity-productivity dependent resistance of an alpine plant community to different climate change scenarios2016In: Ecological research, ISSN 0912-3814, E-ISSN 1440-1703, Vol. 31, no 6, p. 935-945Article in journal (Refereed)
    Abstract [en]

    Here we report from a experiment imposing different warming scenarios [control with ambient temperature, constant level of moderate warming for 3 years, stepwise increase in warming for 3 years, and one season of high level warming (pulse) simulating an extreme summer event] on an alpine ecosystem to study the impact on species diversity–biomass relationship, and community resistance in terms of biomass production.

    Multiple linear mixed models indicate that experimental years had stronger influence on biomass than warming scenarios and species diversity. Species diversity and biomass had almost humpback relationships under different warming scenarios over different experimental years. There was generally a negative diversity–biomass relationship, implying that a positive diversity–biomass relationship was not the case.

    The application of different warming scenarios did not change this tendency. The change in community resistance to all warming scenarios was generally negatively correlated with increasing species diversity, the strength of the correlation varying both between treatments and between years within treatments. The strong effect of experimental years was consistent with the notion that niche complementarity effects increase over time, and hence, higher biomass productivity over experimental years. The strongest negative relationship was found in the first year of the pulse treatment, indicating that the community had weak resistance to an extreme event of one season of abnormally warm climate.

    Biomass production started recovering during the two subsequent years. Contrasting biomass-related resistance emerged in the different treatments, indicating that micro sites within the same plant community may differ in their resistance to different warming scenarios.

  • 50.
    Allard, Alexandra
    et al.
    Linköping Universitet.
    Takman, Johanna
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics.
    Uddin, Gazi Salah
    Linköping Universitet.
    Ahmed, Ali
    Linköping Universitet.
    The N-shaped environmental Kuznets curve: an empirical evaluation using a panel quantile regression approach2018In: Environmental Science and Pollution Research, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 25, no 6, p. 5848-5861Article in journal (Refereed)
    Abstract [en]

    We evaluate the N-shaped environmental Kuznets curve (EKC) using panel quantile regression analysis. We investigate the relationship between CO2 emissions and GDP per capita for 74 countries over the period of 1994–2012. We include additional explanatory variables, such as renewable energy consumption, technological development, trade, and institutional quality. We find evidence for the N-shaped EKC in all income groups, except for the upper-middle-income countries. Heterogeneous characteristics are, however, observed over the N-shaped EKC. Finally, we find a negative relationship between renewable energy consumption and CO2 emissions, which highlights the importance of promoting greener energy in order to combat global warming.

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