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  • 1.
    Abate, Megersa
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi Stockholm, TEK-S.
    Determinants of Capacity Utilisation in Road Freight Transportation2014Inngår i: Journal of Transport Economics and Policy, ISSN 0022-5258, E-ISSN 1754-5951, Vol. 48, s. 137-152Artikkel i tidsskrift (Fagfellevurdert)
    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
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Does fuel price affect trucking industry’s network characteristics?: evidence from Denmark2014Rapport (Annet vitenskapelig)
    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.

    Fulltekst (pdf)
    fulltext
  • 3.
    Abate, Megersa
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Economic effects of air transport market liberalization in Africa2016Inngår i: Transportation Research Part A: Policy and Practice, ISSN 0965-8564, E-ISSN 1879-2375, Vol. 92, s. 326-337Artikkel i tidsskrift (Fagfellevurdert)
    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
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Economic effects of air transport market liberalization in Africa2014Rapport (Annet vitenskapelig)
    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.

    Fulltekst (pdf)
    fulltext
  • 5.
    Abate, Megersa
    et al.
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi Stockholm, TEK-S.
    De Jong, Gerard
    University of Leeds.
    The optimal shipment size and truck size choice: The allocation of trucks across hauls2014Inngår i: Transportation Research Part A: Policy and Practice, ISSN 0965-8564, E-ISSN 1879-2375, Vol. 59, s. 262-277Artikkel i tidsskrift (Fagfellevurdert)
    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.
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi Stockholm, TEK-S.
    Vierth, Inge
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi Stockholm, TEK-S.
    de Jong, Gerard
    University of Leeds.
    Joint econometric models of freight transport chain and shipment size choice2014Rapport (Annet vitenskapelig)
    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.

    Fulltekst (pdf)
    fulltext
  • 7.
    Abate, Megersa
    et al.
    World Bank.
    Vierth, Inge
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Karlsson, Rune
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Trafikanalys och logistik, TAL.
    de Jong, Gerard
    University of Leeds.
    Baak, Jaap
    dSignificance.
    A disaggregate stochastic freight transport model for Sweden2018Inngår i: Transportation, ISSN 0049-4488, E-ISSN 1572-9435, s. 1-26Artikkel i tidsskrift (Fagfellevurdert)
    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
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Trafikanalys och logistik, TAL.
    Cats, Oded
    KTH.
    Susilo, Yusak O.
    KTH.
    What is the role of weather, built-environment and accessibility geographical characteristics in influencing travelers’ experience?2019Inngår i: Transportation Research Part A: Policy and Practice, ISSN 0965-8564, E-ISSN 1879-2375, Vol. 122, s. 34-50Artikkel i tidsskrift (Fagfellevurdert)
    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
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi Stockholm, TEK-S. Örebro universitet, Handelshögskolan vid Örebro Universitet.
    Analysis of discrete multi-unit, common value auctions: a study of three sealed-bid mechanisms2012Manuskript (preprint) (Annet vitenskapelig)
    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
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Energimätning på tåg för rundvirkestransporter på sträckan Mora–Borlänge–Gävle2014Rapport (Annet vitenskapelig)
    Abstract [sv]

    I det tredje delprojektet av ELVIS-demonstrationsprojektet för längre och tyngre godståg är syftet att mäta energianvändningen som ett tyngre tågset ger upphov till. Med tyngre avses här en ökad totalvikt genom fler vagnar, både fullastade och olastade, än vad som normalt körs på sträckan. Antagandet är att det med tyngre tåg finns möjlighet att göra (gods)transporter mer energieffektiva. Målsättningen är att framför allt testa hypotesen: · Att energianvändningen per tonkilometer kan reduceras genom att använda tyngre tåg. Rapporten belyser svårigheterna med att använda befintlig data för utvärdering av vad som driver energianvändningen på tåg. Datat i har inte varit kvalitetssäkrad för ändamålen i denna studie, vilket har orsakat en hel del fel och tillförlitligheten på vissa resultat är lägre än de skulle behöva vara. En slutsats från projektet att det skulle behövas en genomgång av databaserna hos Trafikverket om energianvändning ska studeras närmare, i alla fall om Trafikverkets utrustning för energimätning ska användas. Alternativt bör extern utrustning monteras på loken för att på så vis generera mer ändamålsenlig data, det senare var dock omöjligt då lokägaren inte godkände det. En annan slutsats är att körstilen spelar roll, det skiljer upp till 20 procent använd nettoenergi mellan förarna. Givet alla felkällor har ändå en regressionsanalys gjorts för att analysera hur energianvändningen för ett godståg kan bero på bruttovikten på tåget samt antal stopp tåget gör. Resultaten indikerar att det är skillnader på energianvändning för olika bruttovikter på tåget, men då det är oklart hur resultaten ska tolkas så krävs det mera mätningar för att kunna säga något bestämt. Detsamma gäller för hur antalet stopp påverkar användningen av energi, i en mätning fick vi ingen påverkan på energianvändningen av antal stopp medan vi fick det i en annan.

    Fulltekst (pdf)
    fulltext
  • 11.
    Ahlberg, Joakim
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Intermodala transporter: definition, aktörer och omfattning2016Rapport (Annet vitenskapelig)
    Abstract [sv]

    Intermodala transporter och kombinerade transporter används ofta synonymt idag. Begreppet kombinerade transporter har dock funnits mycket längre och avsåg då transporter där järnvägen och lastbilar kombinerades. Numer räknas en kombinerad transport som att lasten antingen går på järnväg, inre vattenvägar eller till havs och med lastbil, eller mellan två trafikslag där inte lastbil är inkluderat.

    En intermodal transport föregås av ett transportbeslut och för många typer av gods är inte en intermodal transport rimlig, till exempel för virkes- och bulktransporter, medan det för andra varor, såsom detaljhandels- och livsmedelsvaror, finns en valmöjlighet hur godset ska transporteras. Det är då som aktivt beslut kan tas för en intermodal transport, givet att den som äger transportbeslutet känner till transportsättet i fråga. Transportbeslutet är också styrt av tåglägen, finns inte kapacitet på spåren kan inte transporter göras med järnväg. Detta kan potentiellt innebära att vissa (tåg)affärer/transporter inte blir av och godset går på vägen istället.

    Fulltekst (pdf)
    fulltext
  • 12.
    Ahlberg, Joakim
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Kostnader för störningar i infrastrukturen: metodik och fallstudier på väg och järnväg2015Rapport (Annet vitenskapelig)
    Abstract [sv]

    Studien i detta notat belyser metodiken som kan användas vid beräkningar av samhällets kostnader vid störningar i samhällets infrastruktur, framför allt väg- och järnvägstrafik. Ur ett samhällsekonomiskt perspektiv innebär störningar i infrastrukturen kostnader till följd av förseningar, utebliven produktion och kostnader för omledningar med mera. Det är av vikt att beskriva vilken belastning i form av förlorade eller förbrukade resurser som dessa störningar av olika slag innebär för samhället. Utgångspunkten för beräkningen av kostnaderna har varit genom den samhällsekonomiska kalkylen, med kalkylvärden från ASEK (Arbetsgruppen för samhällsekonomisk analysmetod inom transportsektorn); såsom åktidsvärden, förseningstidsvärden samt trängseltidsvärden. Den värdering av tid som görs i transportsektorns samhällsekonomiska kalkyler avser det marginella värdet av en inbesparad timme restid, väntetid eller bytestid för personresor och transporttid för gods.

    Fulltekst (pdf)
    fulltext
  • 13.
    Ahlberg, Joakim
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Luftfartens samhällsekonomiska marginalkostnader: delstudie inom SAMKOST2014Rapport (Annet vitenskapelig)
    Abstract [sv]

    Den här rapporten är en litteraturstudie av luftfartens samhällsekonomiska marginalkostnader. Den utgör ett delprojekt till VTI:s regeringsuppdrag om att uppdatera kunskapen kring trafikens samhällsekonomiska kostnader (SAMKOST). I rapporten diskuteras vilka effekter som är externa för luftfarten, och vilka som redan är internaliserade. Det är inte helt självklart vilka effekter som bör beaktas som relevanta marginalkostnader för luftfarten. Till exempel kan både trängsel och olyckor ses som internaliserade då de redan är omhändertagna av flygledartjänsten, ett verktyg som alla flygplan måste använda sig av i svenskt luftrum enligt lag. Detsamma gäller infrastrukturen. Den stora externa effekten är flygets miljöpåverkan. Här skiljs på tre olika kategorier; bullerpåverkan, luftkvalitépåverkan och klimatpåverkan.

    Fulltekst (pdf)
    fulltext
  • 14.
    Ahlberg, Joakim
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi Stockholm, TEK-S. Örebro universitet, Handelshögskolan vid Örebro Universitet.
    Multi-unit common value auctions: a laboratory experiment with three sealed-bid mechanisms2012Manuskript (preprint) (Annet vitenskapelig)
    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
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi Stockholm, TEK-S. Örebro universitet, Handelshögskolan vid Örebro Universitet.
    Multi-unit common value auctions: an experimental comparison between the static and the dynamic uniform auction2012Manuskript (preprint) (Annet vitenskapelig)
    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
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi Stockholm, TEK-S. Örebro universitet, Handelshögskolan vid Örebro Universitet.
    Multi-unit common value auctions: theory and experiments2012Doktoravhandling, med artikler (Annet vitenskapelig)
    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.

    Delarbeid
    1. Analysis of discrete multi-unit, common value auctions: a study of three sealed-bid mechanisms
    Åpne denne publikasjonen i ny fane eller vindu >>Analysis of discrete multi-unit, common value auctions: a study of three sealed-bid mechanisms
    2012 (engelsk)Manuskript (preprint) (Annet vitenskapelig)
    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
    s. 27
    Emneord
    Economics
    HSV kategori
    Forskningsprogram
    SAB, Qa Economics and finance
    Identifikatorer
    urn:nbn:se:vti:diva-5313 (URN)
    Tilgjengelig fra: 2013-12-03 Laget: 2013-12-03 Sist oppdatert: 2016-02-04bibliografisk kontrollert
    2. Multi-unit common value auctions: a laboratory experiment with three sealed-bid mechanisms
    Åpne denne publikasjonen i ny fane eller vindu >>Multi-unit common value auctions: a laboratory experiment with three sealed-bid mechanisms
    2012 (engelsk)Manuskript (preprint) (Annet vitenskapelig)
    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
    s. 35
    Emneord
    Economics, Ekonomi
    HSV kategori
    Forskningsprogram
    SAB, Qa Economics and finance
    Identifikatorer
    urn:nbn:se:vti:diva-5314 (URN)
    Tilgjengelig fra: 2013-12-03 Laget: 2013-12-03 Sist oppdatert: 2014-06-10bibliografisk kontrollert
    3. Multi-unit common value auctions: an experimental comparison between the static and the dynamic uniform auction
    Åpne denne publikasjonen i ny fane eller vindu >>Multi-unit common value auctions: an experimental comparison between the static and the dynamic uniform auction
    2012 (engelsk)Manuskript (preprint) (Annet vitenskapelig)
    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
    s. 35
    Emneord
    Economics, Ekonomi
    HSV kategori
    Forskningsprogram
    SAB, Qa Economics and finance
    Identifikatorer
    urn:nbn:se:vti:diva-5315 (URN)
    Tilgjengelig fra: 2013-12-03 Laget: 2013-12-03 Sist oppdatert: 2014-06-10bibliografisk kontrollert
    Fulltekst (pdf)
    FULLTEXT01
  • 17.
    Ahlberg, Joakim
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi Stockholm, TEK-S.
    Optimal taxation of intermediate goods in the presence of externalities: A survey towards the transport sector2004Rapport (Annet vitenskapelig)
    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.

    Fulltekst (pdf)
    FULLTEXT01
  • 18.
    Ahlberg, Joakim
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi Stockholm, TEK-S.
    Optimal taxation of intermediate goods in the presence of externalities: A survey towards the transport sector2006Rapport (Annet (populærvitenskap, debatt, mm))
    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.

    Fulltekst (pdf)
    fulltext
  • 19.
    Ahlberg, Joakim
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi Stockholm, TEK-S.
    Revenues in discrete multi-unit, common value auctions: a study of three sealed-bid mechanisms2009Inngår i: Portuguese economic journal, ISSN 1617-9838, Vol. 8, nr 1, s. 21s. 3-14Artikkel i tidsskrift (Fagfellevurdert)
    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
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Ridderstedt, Ivan
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Marginalkostnad för luftfartens infrastruktur2017Rapport (Annet vitenskapelig)
    Abstract [sv]

    Huvudsyftet med denna studie är att skatta marginalkostnaderna för luftfartens infrastruktur, men då det inte finns någon enhetlig definition om vad som är kostnadsbasen för infrastrukturen, det vill säga vad som bör ingå i en marginalkostnadsberäkning, så ingår också ingår också en diskussion kring vilka kostnader som bör inkluderas i en marginalkostnadsberäkning i forskningsfrågan. Ett ytterligare syfte med studien är att relatera de framtagna marginalkostnaderna till dagens prissättning och undersöka huruvida luftfarten betalar sina samhällsekonomiska kostnader.

    Med hjälp av kostnadsdata från Arlanda och från Luftfartsverket skattas marginalkostnaden för utnyttjandet av (relevant) flygplatsinfrastruktur och för infrastrukturen för operativ flygtrafikledning. Den empiriska ansats som använts för att analysera kostnadsposterna är en regressionsanalys, med justering för månadsspecifika variationer i resmönster, då flygplatsdelen undersöks, samt med hänsyn till regionala skillnader för flygplatser, då flygtrafikledning i tornen undersöks.

    Det finns en del osäkerheter i studien, men med bakgrund av detta indikerar resultaten att den genomsnittliga marginalkostnaden för infrastrukturen ligger kring 13 kr per passagerare och 1 168 kr per startat flygplan. Motsvarande skattning för flygtrafikledningen är även den osäker, med resultat som indikerar en marginalkostnad på 373 kr per flygning. Vidare förefaller det som att finansieringen av den statliga luftfartsinfrastrukturen inte enbart skulle kunna ske med intäkterna från marginalkostnadsbaserade avgifter.

    Fulltekst (pdf)
    fulltext
  • 21.
    Ahlberg, Joakim
    et al.
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi Stockholm, TEK-S.
    Johansson, Anna
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi Stockholm, TEK-S.
    Etablering av konkurrerande snabbtågstrafik på Västra stambanan: översyn ur marknadens synvinkel2014Rapport (Annet vitenskapelig)
    Abstract [sv]

    Från oktober 2010 gäller fri konkurrens vad gäller all trafik på järnväg. VTI har intervjuat de tre största operatörer på Västra stambanan för att se hur de upplevde kapacitetsprocessen som ledde fram till tågplanen för 2014 och för att få deras syn på eventuella etableringshinder som kan föreligga på järnvägsmarknaden. Kapaciteten i det svenska järnvägsnätet är per definition begränsad och det finns bara möjlighet att rymma ett visst antal tåg i systemet. Trafikverket fördelar kapaciteten på spåren mellan operatörer som ansöker om tåglägen i en årlig administrativ tilldelningsprocess. I kapacitetstilldelningsprocessen för tågplan 2014 lämnade fyra operatörer in ansökningar om långväga snabbtågstrafik på sträckan Göteborg–Stockholm. I och med att operatörerna i flera fall ansökte om samma tåglägen sattes Trafikverkets tillämpning av samråd, samordning och prioriteringskriterier på prov för första gången sedan marknadsöppningen. De operatörer som utmanar SJ och som vi intervjuat upplever inte att dagens kapacitets-tilldelningsprocess lever upp till kravet på konkurrensneutralitet och icke-diskriminering. Båda ser behov av en mer transparent process, med prioriteringskriterier som ger ett mer förutsägbart utfall och som i större utsträckning tar datoriserade verktyg till hjälp så att den på så sätt både kan genomföras effektivare och ge ett mer effektivt utfall. Alla operatörernas kommentarer av förfarandet visar också att processen med kapacitetstilldelning innehåller ett stort mått av så kallad frivillig samordning för att lösa konflikter kring tåglägen som flera operatörer söker. Detta innebar att operatörerna under slutet av sommaren 2013 sinsemellan samordnade sina önskemål och på så sätt kom överens om vem som fick vilka tåglägen.

    Fulltekst (pdf)
    fulltext
  • 22.
    Ahlberg, Joakim
    et al.
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Nilsson, Jan-Eric
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Ad hoc-processen: hur används ledig kapacitet i järnvägsnätet?2016Rapport (Annet vitenskapelig)
    Abstract [sv]

    Efter Trafikverkets fastställelse av nästkommande års tågplan i mitten av hösten varje år vidtar den så kallade ad hoc-processen, det vill säga ansökningar om tåglägen som kan använda ledig kapacitet i järnvägsnätet. VTI fick i september 2015 Transportstyrelsens uppdrag att fördjupa förståelsen av ad hoc-processen. Detta notat avrapporterar uppdraget.

    Mot bakgrund av den beskrivning som görs har avsikten varit att också hitta mått på betydelsen av denna process i förhållande till den process som leder fram till att en färdig tidplan läggs fast. Det har emellertid visat sig att Trafikverkets olika system för informationshantering inte är utformade för att möjliggöra en sådan beskrivning. Tack vare ett nyligen offentliggjort statistikhjälpmedel är det emellertid möjligt att konstatera att närmare 97 procent av de persontåg som bokats i den ordinarie processen också faktiskt körs. Denna uppgift avser två tredjedelar av tidtabellåret 2015. Avsikten från Trafikverket/Trafikanalys är att inom en nära framtid också redovisa motsvarande information om godstrafiken.

    Bakom denna siffra döljer sig emellertid både ett utflöde från, och ett inflöde till den mängd trafik som ska bedrivas i enlighet med den tidtabell som fastställs under hösten varje år. Det saknas emellertid kunskap om när dessa förändringar genomförs, vilket är av stor betydelse för att bedöma graden av flexibilitet i ad hoc-processen. Denna situation kan komma att förändras som ett resultat av att Trafikverket från och med den tidtabell som avser 2016 inför avgifter för att avboka tilldelad kapacitet. Avgiften blir högre ju närmare det planerade tågets avgång som ansökan tas tillbaka. Detta kan bidra till en förbättrad flexibilitet i användningen av den spårkapacitet som inte reserveras i den ordinarie tidtabellsläggningsprocessen. Ytterligare en konsekvens kan bli att informationen om processen förbättras.

    Fulltekst (pdf)
    fulltext
  • 23.
    Ahlström, Christer
    et al.
    Statens väg- och transportforskningsinstitut, Trafik och trafikant,TRAF, Samspel människa, fordon, transportsystem, MFT.
    Fors, Carina
    Statens väg- och transportforskningsinstitut, Trafik och trafikant,TRAF, Samspel människa, fordon, transportsystem, MFT.
    Forward, Sonja
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Mobilitet, aktörer och planering, MAP.
    Gregersen, Nils Petter
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Mobilitet, aktörer och planering, MAP.
    Hjälmdahl, Magnus
    Statens väg- och transportforskningsinstitut, Trafik och trafikant,TRAF, Samspel människa, fordon, transportsystem, MFT.
    Jansson, Jonas
    Statens väg- och transportforskningsinstitut, Trafik och trafikant,TRAF.
    Kircher, Katja
    Statens väg- och transportforskningsinstitut, Trafik och trafikant,TRAF, Samspel människa, fordon, transportsystem, MFT.
    Lindberg, Gunnar
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi Stockholm, TEK-S.
    Nilsson, Lena
    Statens väg- och transportforskningsinstitut, Trafik och trafikant,TRAF.
    Patten, Christopher
    Statens väg- och transportforskningsinstitut, Trafik och trafikant,TRAF, Samspel människa, fordon, transportsystem, MFT.
    Dangerous use of mobile phones and other communication devices while driving: A toolbox of counter-measures2013Inngår i: Proceedings of the 16th International Conference Road Safety on Four Continents: Beijing, China. 15-17 May 2013, Linköping: Statens väg- och transportforskningsinstitut, 2013Konferansepaper (Annet vitenskapelig)
    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.

    Fulltekst (pdf)
    fulltext
  • 24.
    Ait Ali, Abderrahman
    et al.
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Eliasson, Jonas
    Linköping University.
    European railway deregulation: an overview of market organization and capacity allocation2021Inngår i: Transportmetrica A: Transport Science, ISSN 2324-9935, E-ISSN 2324-9943Artikkel i tidsskrift (Fagfellevurdert)
    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.

    Fulltekst (pdf)
    fulltext
  • 25.
    Ait Ali, Abderrahman
    et al.
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Eliasson, Jonas
    Linköpings universitet.
    Railway capacity allocation: a survey of market organizations, allocation processes and track access charges2019Rapport (Annet vitenskapelig)
    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.

    Fulltekst (pdf)
    fulltext
  • 26.
    Ait Ali, Abderrahman
    et al.
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Eliasson, Jonas
    Linköping University, Sweden.
    The value of additional data for public transport origin: destination matrix estimation2021Inngår i: Public Transport, ISSN 1866-749X, E-ISSN 1613-7159Artikkel i tidsskrift (Fagfellevurdert)
    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).

    Fulltekst (pdf)
    fulltext
  • 27.
    Ait Ali, Abderrahman
    et al.
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    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?2022Inngår i: Transport Policy, ISSN 0967-070X, E-ISSN 1879-310X, Vol. 116, s. 188-198Artikkel i tidsskrift (Fagfellevurdert)
    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

  • 28.
    Ait Ali, Abderrahman
    et al.
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Eliasson, Jonas
    Linköpings universitet.
    Warg, Jennifer
    KTH.
    Are commuter train timetables consistent with passengers’ valuations of waiting times and in-vehicle crowding?2020Rapport (Annet vitenskapelig)
    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.

    Fulltekst (pdf)
    fulltext
  • 29.
    Ait Ali, Abderrahman
    et al.
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Kurt, Filiz
    Deutsches Zentrum für Luft- und Raumfahrt (DLR).
    Isberner, Alessa
    Deutsches Zentrum für Luft- und Raumfahrt (DLR).
    Odolinski, Kristofer
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Berg, Mats
    KTH.
    Assessing innovations in High-Speed Rail infrastructure2023Rapport (Annet vitenskapelig)
    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.

    Fulltekst (pdf)
    fulltext
  • 30.
    Ait Ali, Abderrahman
    et al.
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Kurt, Filiz
    Deutsches Zentrum für Luft-und Raumfahrt, Germany.
    Isberner, Alessa
    Deutsches Zentrum für Luft-und Raumfahrt, Germany.
    Odolinski, Kristofer
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Berg, Mats
    KTH.
    Assessing Innovations in High-Speed Rail Infrastructure2023Inngår i: 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, s. 217-233Konferansepaper (Fagfellevurdert)
    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.

  • 31.
    Ait Ali, Abderrahman
    et al.
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Lidén, Tomas
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Trafikanalys och logistik, TAL.
    Minimal utilization rate for railway maintenance windows: a cost-benefit approach2022Inngår i: European Journal of Transport and Infrastructure Research, ISSN 1567-7133, E-ISSN 1567-7141, Vol. 22, nr 2, s. 108-131Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 32.
    Ait Ali, Abderrahman
    et al.
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Lidén, Tomas
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Trafikanalys och logistik, TAL.
    Minimal utilization rates for railway maintenance windows: a cost-benefit approach2021Rapport (Annet vitenskapelig)
    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.

    Fulltekst (pdf)
    fulltext
  • 33.
    Ait Ali, Abderrahman
    et al.
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Lindberg, Per Olov
    Eliasson, Jonas
    Linköping University.
    Nilsson, Jan-Eric
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Peterson, Anders
    Linköping University.
    A disaggregate bundle method for train timetabling problems2020Inngår i: Journal of Rail Transport Planning & Management, ISSN 2210-9706, E-ISSN 2210-9714, artikkel-id 100200Artikkel i tidsskrift (Fagfellevurdert)
    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

  • 34.
    Ait Ali, Abderrahman
    et al.
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Odolinski, Kristofer
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Pålsson, Björn
    Mechanics and Maritime Sciences/CHARMEC, Chalmers.
    Torstensson, Peter
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Miljö, MILJÖ.
    Evaluating the mix of maintenance activities on railway crossings with respect to life-cycle costs2023Rapport (Annet vitenskapelig)
    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.

    Fulltekst (pdf)
    fulltext
  • 35.
    Ait Ali, Abderrahman
    et al.
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Pålsson, Björn
    Chalmers University of Technology, Department of Mechanics and Maritime Sciences/CHARMEC, Sweden.
    Odolinski, Kristofer
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Torstensson, Peter
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Miljö, MILJÖ.
    Evaluation of long-term maintenance of switches & crossings with respect to life-cycle costs and socio-economic impact2022Konferansepaper (Annet vitenskapelig)
    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.).

    Fulltekst (pdf)
    PowerPoint
  • 36.
    Ait Ali, Abderrahman
    et al.
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Warg, Jennifer
    KTH.
    Eliasson, Jonas
    Linköpings universitet.
    Pricing commercial train path requests based on societal costs2019Rapport (Annet vitenskapelig)
    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.

    Fulltekst (pdf)
    fulltext
  • 37.
    Ait Ali, Abderrahman
    et al.
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK. Linköping University.
    Warg, Jennifer
    KTH Royal Institute of Technology.
    Eliasson, Jonas
    Linköping University.
    Pricing commercial train path requests based on societal costs2020Inngår i: Transportation Research Part A: Policy and Practice, ISSN 0965-8564, E-ISSN 1879-2375, Vol. 132, s. 452-464Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 38.
    Alatalo, Juha M
    et al.
    Uppsala Universitet, Campus Gotland.
    Jägerbrand, Annika K
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Miljö, MILJÖ.
    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 tundra2014Inngår i: Alpine Botany, ISSN 1664-2201, Vol. 124, nr 2, s. 81-91Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 39.
    Alatalo, Juha M
    et al.
    Qatar University.
    Jägerbrand, Annika K
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Miljö, MILJÖ.
    Molau, Ulf
    Göteborgs Universitet.
    Impacts of different climate change regimes and extreme climatic events on an alpine meadow community2016Inngår i: Scientific Reports, E-ISSN 2045-2322, Vol. 6, artikkel-id 21720Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 40.
    Alatalo, Juha M.
    et al.
    Uppsala Universitet.
    Jägerbrand, Annika
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Miljö, MILJÖ.
    Molau, Ulf
    University of Gothenburg.
    Seven years of experimental warming and nutrient addition causes decline of bryophytes and lichens in alpine meadow and heath communitiesManuskript (preprint) (Annet vitenskapelig)
    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.

    Fulltekst (pdf)
    fulltext
  • 41.
    Alatalo, Juha, M.
    et al.
    Uppsala Universitet.
    Jägerbrand, Annika
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Miljö, MILJÖ.
    Molau, Ulf
    Göteborgs Universitet.
    Testing reliability of short-term responses to predict longer-term responses of bryophytes and lichens to environmental change2015Inngår i: Ecological Indicators, ISSN 1470-160X, E-ISSN 1872-7034, Vol. 58, s. 77-85Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 42.
    Alatalo, Juha M
    et al.
    Qatar University.
    Jägerbrand, Annika
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Miljö, MILJÖ.
    Čuchta, Peter
    Academy of Science of the Czech Republic.
    Collembola at three alpine subarctic sites resistant to twenty years of experimental warming2015Inngår i: Scientific Reports, E-ISSN 2045-2322, Vol. 5, artikkel-id 18161Artikkel i tidsskrift (Fagfellevurdert)
    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.

    Fulltekst (pdf)
    fulltext
  • 43.
    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
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Miljö, MILJÖ.
    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 change2014Inngår i: PeerJ, E-ISSN 2167-8359, Vol. 2, artikkel-id e406Artikkel i tidsskrift (Fagfellevurdert)
    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.

    Fulltekst (pdf)
    fulltext
  • 44.
    Alatalo, Juha, M.
    et al.
    Uppsala Universitet.
    Little, Chelsea, J.
    Uppsala Universitet.
    Jägerbrand, Annika
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Miljö, MILJÖ.
    Molau, Ulf
    Göteborgs Universitet.
    Vascular plant abundance and diversity in an alpine heath under observed and simulated global change2015Inngår i: Scientific Reports, E-ISSN 2045-2322, Vol. 5, s. 1-11, artikkel-id 10197Artikkel i tidsskrift (Fagfellevurdert)
    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.

    Fulltekst (pdf)
    fulltext
  • 45.
    Aldenius, Malin
    et al.
    Lund University.
    Tsaxiri, Panagiota
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Trafikanalys och logistik, TAL. Linköping University.
    Lidestam, Helene
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Trafikanalys och logistik, TAL. K2.
    The role of environmental requirements in Swedish public procurement of bus transports2021Inngår i: International Journal of Sustainable Transportation, ISSN 1556-8318, E-ISSN 1556-8334, Vol. 16, nr 5, s. 391-405Artikkel i tidsskrift (Fagfellevurdert)
    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.

    Fulltekst (pdf)
    fulltext
  • 46.
    Alexandersson, Gunnar
    et al.
    Stockholm School of Economics Institute for Research, Sweden.
    Andersson, Matts
    WSP Advisory, Sweden.
    Bondemark, Anders
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    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 network2022Inngår i: Annals of Public and Cooperative Economics, ISSN 1370-4788, E-ISSN 1467-8292Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 47.
    Alexandersson, Gunnar
    et al.
    Stockholm school of economics.
    Hultén, Staffan
    Stockholm school of economics.
    Nilsson, Jan-Eric
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi Stockholm, TEK-S.
    Pyddoke, Roger
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi Stockholm, TEK-S.
    The liberalization of railway passenger transport in Sweden: outstanding regulatory challenges2012Rapport (Annet vitenskapelig)
    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.

    Fulltekst (pdf)
    fulltext
  • 48.
    Ali, Arshad
    et al.
    East China Normal University.
    Molau, Ulf
    Göteborgs Universitet.
    Bai, Yang
    Chinese Academy of Sciences.
    Jägerbrand, Annika K
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Miljö, MILJÖ.
    Alatalo, Juha M.
    Qatar University.
    Diversity-productivity dependent resistance of an alpine plant community to different climate change scenarios2016Inngår i: Ecological research, ISSN 0912-3814, E-ISSN 1440-1703, Vol. 31, nr 6, s. 935-945Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 49.
    Allard, Alexandra
    et al.
    Linköping Universitet.
    Takman, Johanna
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Transportekonomi, TEK.
    Uddin, Gazi Salah
    Linköping Universitet.
    Ahmed, Ali
    Linköping Universitet.
    The N-shaped environmental Kuznets curve: an empirical evaluation using a panel quantile regression approach2018Inngår i: Environmental Science and Pollution Research, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 25, nr 6, s. 5848-5861Artikkel i tidsskrift (Fagfellevurdert)
    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.

    Fulltekst (pdf)
    fulltext
  • 50.
    Allström, Andreas
    et al.
    Sweco.
    Kristoffersson, Ida
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Trafikanalys och logistik, TAL. Kungliga Tekniska Högskolan.
    Susilo, Yusak
    KTH.
    Smartphone based travel diary collection: Experiences from a field trial in Stockholm2017Inngår i: Transportation Research Procedia, Elsevier B.V. , 2017, Vol. 26, s. 32-38Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Currently, there is a great need for new methods to collect travel data. Traditional methods have considerable drawbacks and, at the same time, the models used to analyse the transport system require more and more detailed and high-quality data. Since most smartphones are equipped with various sensors that can be used to determine the location of the smartphone, and since smartphones are integrated in the daily life of most people, they provide an unprecedented opportunity for large-scale travel data collection. This method has a great potential to solve the problems related to the estimation of distance/travel time, geographic coding of departure/destination locations and forgotten trips and it will also provide a more detailed and extensive data set.

    In a recently completed research project the feasibility of replacing or complementing the traditional travel diary, with a suite of tools that make use of smartphone collected travel data has been evaluated. The advantages and disadvantages of the traditional method and the proposed method were studied. For a fair comparison, both methods have been tested in the same city, at the same time, and with the same respondents. To achieve the objectives of the project, MEILI, a system that consists of a smartphone application for capturing the movement of users and a web application for allowing the users to annotate their movement, has been deployed. In total 2142 trips were collected and annotated by 171 users. 51 of the users annotated trips covering more than a week. The main findings of the paper are that smartphone based data collection is feasible, that the algorithms to save battery work well and that trips of the same respondent vary considerably depending on day of the week.

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