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  • 1.
    Bång, Karl-Lennart
    et al.
    Kungliga Tekniska Högskolan, KTH, Stockhollm.
    Olstam, Johan
    Linköpings universitet, Kommunikations- och transportsystem.
    Köhler, Joakim
    WSP, Parsons Brinckerhoff, UK.
    Wahlstedt, Johan
    Kungliga Tekniska Högskolan, KTH, Stockholm.
    Andersson, Jonas
    Tyréns AB, Stockholm.
    Handbok för kapacitetsanalys med hjälp av simulering2014Report (Other academic)
    Abstract [sv]

    Syftet med föreliggande handbok är att beskriva hur trafiksimulering kananvändas som en alternativ metod eller komplement till analytiska metoderför att bestämma kapacitet och framkomlighet. Liksom metodbeskrivningarnai TRV2013/64343 är beskrivningarna avsedda att kunna användas för att medhjälp av trafiksimulering uppskatta effekterna av en given utformning isamband med planering, konsekvensanalys, projektering och drift avvägtrafikanläggningar. Simulering kan användas som ett komplement till deanalytiska metoderna, eller som ersättning i fall som inte täcks av dessametoder. Härigenom minskas risken för onödiga kostnader förorsakade avsåväl över- som underkapacitet.

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    FULLTEXT01
  • 2.
    Grumert, Ellen
    et al.
    Statens väg- och transportforskningsinstitut, Trafikanalys och logistik, TAL.
    Bernhardsson, Viktor
    Statens väg- och transportforskningsinstitut, Trafikanalys och logistik, TAL.
    Strömgren, Per
    Movea.
    Gundlegård, David
    Linköpings universitet.
    Olstam, Johan
    Statens väg- och transportforskningsinstitut, Trafikanalys och logistik, TAL.
    Ekström, Joakim
    Linköpings universitet.
    Ringdahl, Rasmus
    Linköpings universitet.
    Effects of incidents on motorways: a proposed methodology for estimating and predicting demand, duration and capacity for incident management2021Report (Other academic)
    Abstract [en]

    Effective traffic incident management is important to minimize negative impacts of congestion caused by incidents. Predictions of the traffic state at the incident site and its surrounding road network, together with an estimate of incident duration, can be used to get increased knowledge about current and future incident characteristics. 

    The aim is to propose methods for estimating capacity, duration and demand profiles in case of an incident, and to explore how the level of detail and the possibility to identify explanatory variables for incidents with similar characteristics given currently available data sources affects the proposed methods. The knowledge obtained within the project is intended to be used for incident management. 

    The report presents a methodology for predicting capacity, traffic demand, and incident duration, when none of the parameters are known. The proposed methods can be used as input to traffic models, when the purpose is to perform scenario-based analysis and real-time predictions to be used in the decision-making processes for traffic management/control, but also for predicting travel times which can be communicated to road users.

    A motorway use-case study area south of Stockholm is used to propose methods for predicting incident duration, capacity and demand profiles based on the availability of data. The methodology is evaluated by using the predicted variables as input in a scenario-based analysis with two queue models.

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    FULLTEXT01
  • 3.
    Johansson, Fredrik
    et al.
    Statens väg- och transportforskningsinstitut, Trafikanalys och logistik, TAL.
    Liu, Chengxi
    Statens väg- och transportforskningsinstitut, Trafikanalys och logistik, TAL.
    Ekström, Joakim
    Linköpings universitet.
    Olstam, Johan
    Statens väg- och transportforskningsinstitut, Trafikanalys och logistik, TAL.
    Cykeltrafikmodellering: behovsanalys och kunskapsläge2020Report (Other academic)
    Abstract [en]

    There is a lack of traffic models for bicycle traffic which implies difficulties to plan for effective, safe and attractive bicycle infrastructure. The aim of this pre-study is to identify needs for future research and model development in Sweden within the field of bicycle traffic modelling, and in this way guide future efforts in the field. The pre-study was conducted in two stages: practitioners’ needs of traffic models for decision support and research needs for microscopic and macroscopic traffic models. Interviews with consultants and a workshop with representatives from municipalities, regions, and the Swedish Transport Administration were conducted in order to investigate practitioners’ needs of bicycling traffic models to support cycling traffic planning and their view of the need for future research and model development in Sweden. Literature reviews were conducted to summarize the current state-of-the-art on bicycling traffic model. The practitioners’ needs together with the state-of-the-art suggest that there is a clear need for further research and development of both microscopic and macroscopic bicycling traffic models. A crucial part for development and application of both model types is access to data. For macroscopic models there is a need of development of mode choice models that includes bicyclist as well as route choice models. For microscopic traffic models, the starting point should be car traffic inspired traffic models or social force models, or if necessary, development of new modelling approaches.

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    FULLTEXT01
  • 4.
    Olstam, Johan
    Statens väg- och transportforskningsinstitut, Trafikanalys och logistik, TAL.
    Kalibrering av restidsfunktioner: förslag till metodik och datainsamlingsupplägg2017Report (Other academic)
    Abstract [en]

    Route choice calculations in static traffic assignment models (as Emme, Visum, TransCad) are based on travel time estimations using volume delay functions. The volume delay function (also denoted travel time functions) describe how the travel time depend on the traffic volume for different types of roads. The volume delay functions are one of the base elements in travel prognosis models as the Swedish Sampers model system. This report presents a pre-study with the aim to investigate how volume delay functions should be designed and calibrated, including which road classification to use, which type of volume delay function that should be used, how the functions should be calibrated and which data that is needed for the calibration. These questions were investigated by a literature review on state-of-practice, workshops with experienced Sampers users to collect information and experiences of the current volume delay functions in Sampers, workshops with research experts on data collection of travel times, and project internal discussions on calibration methodologies.

    The literature review showed that there are few guidelines on how volume delay functions can or should be calibrated. The calibration is commonly conducted by fitting the volume delay function curve to cross-sectional measurements of flow and mean speed. There are some examples of calibration based on travel time measurements based on floating car measurements or number plate recognition. These calibration approaches focus on describing travel time for a given link based on the flow at the link. However, based on the literature review and experience from earlier research in Sweden it is concluded that volume delay functions that represent the traffic process on a road link in a good way do not necessary give a good fit of the static assignment calculated and observed link and route flows and travel times. There are several attempts described in the literature of calibration approaches that aim to minimize the difference between model calculated and observed flows and travel times using optimization techniques. The suggestion from the pre-study is that such an approach should be investigated for calibration of the Sampers volume delay functions. To avoid overfitting and unrealistic parameters values the optimization should include lower and upper limits of the parameters.

    The calibration requires both link flow and travel time observations. Link counts are regularly measured for other purposes and can be collected from the Swedish Transport Administration and municipality regular traffic measurement programs. The suggestion for travel time data is to use the travel time data that currently is commissioned by the Swedish Transport Administration and Stockholm and Göteborg municipality. Our recommendation is also that the Swedish Transport Administration investigate the possibility to buy travel time data for the Swedish main road network.

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    FULLTEXT01
  • 5.
    Vadeby, Anna
    et al.
    Statens väg- och transportforskningsinstitut, Trafiksäkerhet och trafiksystem, TST.
    Anund, Anna
    Statens väg- och transportforskningsinstitut, Trafikanttillstånd, TIL.
    Ekström, Camilla
    Statens väg- och transportforskningsinstitut, Trafiksäkerhet och trafiksystem, TST.
    Gustafsson, Susanne
    Statens väg- och transportforskningsinstitut, Trafiksäkerhet och trafiksystem, TST.
    Lundberg, Thomas
    Statens väg- och transportforskningsinstitut, Drift och underhåll, DOU.
    Olstam, Johan
    Statens väg- och transportforskningsinstitut, Trafikanalys och logistik, TAL.
    Tapani, Andreas
    Statens väg- och transportforskningsinstitut, Trafikanalys och logistik, TAL.
    Säker framkomlighet: sammanfattande slutrapport 20152016Report (Other academic)
    Abstract [en]

    This report consolidates evaluations performed within the project “Safe accessibility” on behalf of the Swedish Transport Administration. Four different measures implemented on rural roads in Sweden with the aim to increase traffic safety and improve accessibility are investigated. The measures are; milled centerline rumble strips on rural 2-lane roads, shoulder rumble strips on motorways, narrow2+1 roads with median barrier and divided roads (painted 2+1 roads with median rumble strips).As regards traffic safety, all four measures show reductions in the number of fatalities and seriously injured. For milled centerline rumble strips on rural 2-lane roads, they do not have a confining effect on traffic and have no adverse effect on the rate of rutting. For barrier separated roads (2+1), the results indicated that for Average Annual Daily Traffic (AADT) levels greater than 8,000 vehicles, the annual rut depth development rate is about 25 percent higher than for conventional rural roads. With lower AADT levels, differences reduced to between 10–15 percent. Comparisons between divided roads and conventional roads only showed higher annual rut development rates for AADT levels greater than 8,000 vehicles. A study about the effects and consequences of different types of milled rumble strips showed that there are no known arguments for not using the sinus rumble strips. However, further studies on the impact of drivers of heavy vehicles are recommended. Studies of the effect on traffic efficiency showed that the proportion of Heavy Goods Vehicles (HGVs) is an important factor to consider in the design of narrow 2+1 roads and the proportion of HGVs need to be taken into account in the selection of the length of overtaking lanes.

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    FULLTEXT01
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