1 - 9 of 9
rss atomLink to result list
Permanent link
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
  • Odolinski, Kristofer
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics, TEK.
    Genell, Anders
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Janhäll, Sara
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Samhällsekonomiska effekter med en kombitransport: beräkningar på järnvägsvagnen Flexiwaggon2017Report (Other academic)
    Abstract [en]

    In Sweden and the EU, there is a stated need to combine more freight transports on road with railway. The aim is to reduce emissions of climate gases, as well as noise and other external effects such as congestion, accidents and wear and tear of the road. New innovations and transport solutions can be necessary to increase the number of combined road and railway freight transports. The transport solution analyzed in this study is a new railway wagon that can transport trucks at the speed of 160 km/h. The purpose of the study is to calculate the economic effects the new railway wagon can generate if it is used on a route where rail can be a viable alternative to road transport. In this, the environment and energy effects are studied, as well as the commercial cost.

    To define the contestable market between transport modes in a certain situation can be a challenging task, as there are many – and often interacting – factors that determine the mode choice. However, the literature states that route distance and the characteristics of the goods being transported are crucial factors for mode choice, where examples of the characteristics of goods are its value, damage sensitivity, time sensitivity, and weight (these can to a large extent be captured by the type of good). Freight transport on rail are often considered to be a viable approach on distances over 300 kilometres. In this study, we use three project cases with the route distances 280, 420 and 670 kilometres. We assume that distinct groups of goods are transported, as this will have an impact on the calculations.

    The base cases (with the abbreviation JA in the study) comprises road transport carried out by trucks with a trailer. A major part of the distance in the project cases (abbreviated UA) is covered by trains on which the trucks have been loaded. There are no truck drivers on the train transport.

    The environment and energy effects (exclusive noise) are calculated using a tool provided by the Network for Transport Measures (NTM). Differences in carbon dioxide, methane, nitrous oxide, sulfur dioxide, carbon monoxide, nitrogen oxides, and particulate matter are presented, where the project cases have lower emissions than the base cases. Moreover, a lower amount of energy is consumed in the project cases compared to the base cases.

  • Börjesson, Maria
    et al.
    KTH, Centrum för transportstudier, CTS.
    Eliasson, Jonas
    KTH, Centrum för transportstudier, CTS.
    Levander, A
    The value of time of car drivers choosing route: evidence from the Stockholm congestion charging trial2007In: Proceedings of the European Transport Conference, Leiden, Netherlands, 2007, 14- p.Conference paper (Refereed)
    Abstract [en]

    In applied travel demand forecasting (including network modeling), congestion charges are generally assumed to affect travelers in the same way as fuel costs and other travel costs do. However, there are several reasons to believe that congestion charges affect drivers differently than for example fuel costs: for exampel, it is more “visible”, since you (as a rule) pay each time you pass a cordon (or equivalent), and it is often connected with a certain amount of hassle to actually pay the charge (calling a customer service, for example). Moreover, the way car drivers actually weigh travel time versus monetary cost when they choose route is largely unknown, since time and monetary cost are in general so correlated (as opposed to values of time in mode choice etc.). 

    Data from the Stockholm congestion charging trial allow us to explore this question in detail. Car drivers traveling between the northern part of the county and the southern part could choose either to go through the cordon (paying two charges – 20-40 SEK depending on the time of day) or use the Essinge bypass, which was free of charge – a considerable detour for some trip relations. We use a large panel travel survey conducted before and during the charging trial to estimate the charging cost sensitivity compared to fuel cost sensitivity, and also estimate the actual value of time car drivers reveal when choosing route. Note that due to e.g. selection bias or travelers’ imperfect information about costs, this value of tme may differ from the average value of time for all travelers and also from the average value time for car drivers. The results is very applicable, in that it is easily incorporated into widely used traffic models (network equilibrium models or equivalent), allowing us to make more precise forecasts of the effects of congestion charges. It should also allow us to make more precise route choice modeling in other cases where routes have clearly different monetary costs.

  • Börjesson, Maria
    et al.
    Eliasson, Jonas
    Kostnadseffektivitet i valet av infrastrukturinvesteringar2015Report (Other academic)
    Abstract [sv]

    Rapporten är upplagd på följande sätt. I kapitel 2 beskrivs vad som ingår i en samhällsekonomisk kalkyl och hur den tas fram. Kapitel 3 redovisar våra slutsatser om hur samhällsekonomiska kalkyler påverkar beslut om infrastrukturinvesteringar. I kapitel 4 diskuteras vanliga invändningar mot kalkyler, till exempel att inte alla effekter finns med eller att den är att resultatet påverkas starkt av antagande om förutsättningar, till exempel framtida bränslepriser etc. Kapitel 5 diskuterar mer utförligt vad det svaga sambandet mellan samhällsekonomisk effektivitet och beslut kan bero på, vilka problem det kan leda till och vad man skulle kunna göra åt det för att få en effektivare resursanvändning i transportsektorn.

  • Börjesson, Maria
    KTH, Transporter och samhällsekonomi (stängd 20110301).
    Issues in Urban Travel Demand Modelling: ICT Implications and Trip timing choice2006Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Travel demand forecasting is essential for many decisions, such as infrastructure investments and policy measures. Traditionally travel demand modelling has considered trip frequency, mode, destination and route choice. This thesis considers two other choice dimensions, hypothesised to have implications for travel demand forecasting. The first part investigates how the increased possibilities to overcome space that ICT (information and communication technology) provides, can be integrated in travel demand forecasting models. We find that possibilities of modelling substitution effects are limited, irrespective of data source and modelling approach. Telecommuting explains, however, a very small part of variation in work trip frequency. It is therefore not urgent to include effects from telecommuting in travel demand forecasting. The results indicate that telecommuting is a privilege for certain groups of employees, and we therefore expect that negative attitudes from management, job suitability and lack of equipment are important obstacles. We find also that company benefits can be obtained from telecommuting. No evidences that telecommuting gives rise to urban sprawl is, however, found. Hence, there is ground for promoting telecommuting from a societal, individual and company perspective.

    The second part develops a departure time choice model in a mixed logit framework. This model explains how travellers trade-off travel time, travel time variability, monetary and scheduling costs, when choosing departure time. We explicitly account for correlation in unobserved heterogeneity over repeated SP choices, which was fundamental for accurate estimation of the substitution pattern. Temporal constraints at destination are found to mainly restrict late arrival. Constraints at origin mainly restrict early departure. Sensitivity to travel time uncertainty depends on trip type and intended arrival time. Given appropriate input data and a calibrated dynamic assignment model, the model can be applied to forecast peak-spreading effects in congested networks. Combined stated preference (SP) and revealed preference (RP) data is used, which has provided an opportunity to compare observed and stated behaviour. Such analysis has previously not been carried out and indicates that there are systematic differences in RP and SP data.

  • Börjesson, Maria
    KTH, Infrastruktur.
    Communication technology and travel demand models2003Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Transportation planners have traditionally focused onphysical travel only, and disregarded the fact that other modesof communication may influence travel demand. However, moderntelecommunications are rapidly increasing the accessibility toactivities that previously only could be reached by physicaltransportation. This development calls for methods to analyseinteractions between telecommunications and transport systems.The objective of this thesis is to accomplish a betterunderstanding of if and how impacts of information technologycould be implemented in travel demand models. An important partof this issue is to investigate what kind of data that isneeded.

    This thesis also aims at investigating whether theCommunication Survey, KOM, collected by Swedish Institute forTransport and Communications, SIKA, can be used to improvetransport modelling with respect to how moderntelecommunications influence travel demand. KOM is a one-daytravel and communication diary survey, including information onthe respondents telecommuting habits as well as socio-economicstatus. One problem was the small sample size in KOM, whichmade the analyses uncertain. Since KOM is collected on a yearlybasis, it is still possible to apply similar analysis methodswithin a few years, using a larger data set, which might enableextended analyses. The small sample in KOM available to date isbest suited for general descriptive analyses of communicationpatterns in Sweden. The main conclusions of the paper aretherefore connected to the methods and future datacollection.

    The thesis includes three papers. The first paper tested amodel approach that assumes substitution between travel andnon-travel based communication, using the KOM database. Traveldemand models are in general constructed as nested logit modelswith frequency, mode and destination choice levels. In thepaper, non-travel based modes of communication were included inthe choice set of such a model. The non-travel based modes ofcommunication considered were Internet (and e-mail), ordinarymail and telephone contacts. The model was developed for postand bank activities only, since that was the only activity forwhich the numbers of contacts and trips were large enough toallow model estimation. Several conclusions could be drawn.Describing the utility of the non-travel based alternatives isdifficult and needs more research. The analysisis also verysensitive to how activities are defined. It is furtheressential that the data collection is more process orientedthan traditional cross-sectional data is when analysing traveland telecommunications interactions. That is, habits ofperforming particular activities, including both trips anddifferent types of contacts, must be studied. The second andthird papers investigate telecommuting. As a first step toreach the goal of forecasting telecommuting, the second paperexamined the characteristics of current telecommuters by use ofKOM. This was mainly accomplished by estimating a telecommutingadoption model of logit type. However, only 122 employees outof 7578 actually telecommutes full days at home. Thesetelecommuters work primarily in information- and service-basedindustrial sectors concerned with computers, finance orcommunication. The difficulties in describing the utility ofthe telecommunications based alternatives (representing”no travel”) concerned also the telecommutingadoption model. Also impacts on travel from telecommuting wereinvestigated. Comparing the average commuting distance showedthat employees who exclusively telecommute full days havelonger commuting distances than others, but that othertelecommuters do not have longer average commuting distances.Telecommuting in general does not seem to be influenced by lowaccessibility to the labour market.

    The third paper used data collected from a working sitewithin the company Ericsson, located in the office district ofNacka Strand in Stockholm during the autumn 2002. Thetelecommuting frequency was substantially higher at Ericssonthan in the workforce as a whole. The propensity to adopttelecommuting was modelled as a function of socio-economicvariables and access to technical equipment, work tasksuitability and management attitudes, as perceived by theemployees. The focuswas to identify tools that the company canuse to promote telecommuting, and to find incentives for thecompany to promote telecommuting. Technical equipment, suitablework tasks and managers attitude were identified as constraintsfor telecommuting. The employees also perceived that theybecame more efficient and saved time when telecommuting.

  • Bernhardsson, Viktor
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Olstam, Johan
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Effektiva omkörningsfält på 2+1-vägar: trafiksimuleringar av olika utformningsalternativ ur ett framkomlighetsperspektiv2017Report (Other academic)
    Abstract [en]

    The traffic performance at oncoming lane separated highways with alternating dedicated overtaking lanes (so called 2+1 roads), is dependent on the share of two lane segments (also known as the share of overtaking length). In order to maximize utilization and traffic performance, the configuration of the overtaking lanes should be designed to avoid congestion and delays. Short overtaking lanes implies limited time of queue discharge, but gives frequently recurring possibilities to overtake. Increased lengths of overtaking lanes imply the possibility to overtake several vehicles per overtaking lane, but increases the risk of catching up slower vehicles since the configuration also results in increased lengths of one lane segments.

    This report presents a traffic simulation study of how different configurations affects the throughput at 2+1 roads. The results indicate that overtaking lanes between 1 050 and 1 400 meters result in shortest travel time. However, the differences are small (~0.4 seconds/km) and not statistically significant. Thus, the benefit of optimizing the configuration in terms of throughput could be questioned. Based on the results, it becomes reasonable to question the concept of designing 2+1 roads with long overtaking lengths (which corresponds to the recommendations from the Swedish Transport Administration (Trafikverket)). The major risk of catching up a slower vehicle at the one lane segments obviously affects the travel time.

  • Hellman, Fredrik
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Eklöf, Ingemar
    Novus Ecosystems.
    Kraft, Lars
    CBI Betonginstitutet.
    Återvinning av däck i anläggningskonstruktioner: bättre resursutnyttjande av ett högvärdigt material2017Report (Other academic)
    Abstract [en]

    Rubber has special properties compared to other materials. When used tires are recycled it results in products which largely retains the original technical characteristics of rubber. It is, for example soft, insulating, regains its original shape after a load and is durable. These properties can be utilized to produce products and structures with unique properties. For example; products that can withstand greater deformation without breaking, which dampen vibrations and noise, which has an insulating ability, purifying and stabilizing abilities and products. We can also add that it is persistent over time.

    The construction industry has traditionally used mostly either unbound granular materials, (sand and rock material) or bound material (asphalt, concrete). Rubber material in the form of granules, for example, tire clip or the entire tyre offers unparalleled opportunities to perform new types of civil engineering structures with special advantages compared to traditional structures. Well known examples of how to create a new type of constructions based on the specific properties of rubber are artificial grass with rubber granules and appropriate soft protective coatings for playgrounds.

    There are great potentials to develop constructions with unique properties where recycled material forms or is part of the construction, and will be wanted for its function and become profitable.

    A basic problem, regardless of applications, is that this involves two different value chains and a natural link between these are missing. One value chain is construction and civil engineering and the other is the recycling of waste and residue products. These value chains have traditionally completely different focus in aim and purpose for businesses, so the desirable relationship with both “push and pull” is not naturally occurring. To create this link, some party must take responsibility for the need and the role that arise at the intersection of these value chains. Who takes this role is the leaping issue for further processing, manufacturing and managing where recycled tires wholly or partly constitute the raw material.

  • Österström, Johannes
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics, TEK.
    Upphandling av vägkvalitet: en kartläggning av kvalitetsbegreppet i väginvesteringar2017Report (Other academic)
    Abstract [en]

    The concept of road quality is multifaceted. This report concludes that the complexity of the concept can be managed by defining it on governments transport policy of economic efficiency and long-term sustainable transport system. Then the quality concept regarding roads can be approached in the following ways:

    • • A road gives social benefits in terms of accessibility – the ability for road users to move between different locations. Lack of accessibility may occur in the form of e.g. reduced speed or a closed road. Good quality is therefore an open road that fulfils the capacity, speed, safety and comfort for which it is designed.
    • Time is an important variable for quality. All roads are of good quality when they open for traffic, but will deteriorate over time.
    • Costs constitute a reference to which all quality measures must be related. In a relative measurement for quality, efficiency is upheld when that last SEK is spent where it gives most value. For this relative measure of quality, all costs during the life of the road are relevant, whether they concern the investment itself or the subsequent maintenance.

    Hence quality in roads is a complex concept, which contains all three of these aspects.

    The next question is how to measure them. Three different approaches for measuring quality will be presented. The first source is customer satisfaction and accident statistics. A problem with customer surveys is that the respondents tend to focus on comfort at the expense of security issues. This because the low risk of traffic accidents makes the respondents not fully able to take in the risk aspects. Accident statistics are uncertain since it is difficult to connect the accident directly to the road quality.

    A second source for quality data is the Swedish Transport Administration’s internal quality control for projects. The review of this process on a subproject in the large Förbifart Stockholm, indicates that the controls in many respects are extensive. However, the Swedish Transport Administration has implemented a reform to use more design-build contracts, that entails more self-reporting from the contractor. In a longer perspective, this risks Swedish Transport Administration’s ability for insight into the actual implementation of a road project and the measure of quality.

    The third source of information on road quality refers to road surface. There is extended research into this topic on how and what to measure. This type of information should therefore be used as a basis for monitoring road network quality. The report goes on suggesting two indexes to define quality from physical aspects of the road, one for the surface and one for structure. For the surface, an index is created by weigh track depth, IRI and texture. The structural index combines, track area, crosssectional variation, edge depth and deflection. Since physical aspects of quality only is relevant to measure a few years after the road is opened for traffic, other affecting variables need to be controlled for.

  • Barreto, Camila Belleza Maciel
    et al.
    LabTrans/UFSC, Florianópolis, Brazil.
    Valente, Amir Mattar
    LabTrans/UFSC, Florianópolis, Brazil.
    Tani, Valter Zanela
    LabTrans/UFSC, Florianópolis, Brazil.
    Mariano, Carolina Iris Brasil
    LabTrans/UFSC, Florianópolis, Brazil.
    Reibnitz, Ricardo Rogério
    LabTrans/UFSC, Florianópolis, Brazil.
    Mori, Flavio De
    LabTrans/UFSC, Florianópolis, Brazil.
    Traffic crashes in work zones: an overview of the Brazilian federal highways2016Conference paper (Refereed)
    Abstract [en]

    This paper presents an overview of work zone crashes in Brazilian federal highways undergoing lane addition. For the purpose of the study, nine segments of highway construction under the jurisdiction of DNIT were analyzed throughout several states in Brazil during the year of 2013. The results show that the accident rate per kilometer in work zone stretches was higher than the accident rate across the entire paved network. While the paved roads had a rate of 2.44 crashes per kilometer, the assessed work zone stretches showed a rate of 4.06 crashes per kilometer. Furthermore, the rate of crashes with injuries and deaths was higher in segments with work zones. This situation can be minimized by implementing more efficient signaling in these segments, as well as the adoption of ITS, seeking to ensure the safety of road users and traffic flow.