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  • 1.
    Aria, Erfan
    et al.
    Linköpings universitet.
    Olstam, Johan
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Trafikanalys och logistik, TAL.
    Schwietering, Christoph
    Schwietering Traffic Engineers, DE.
    Investigation of Automated Vehicle Effects on Driver's Behavior and Traffic Performance2016Ingår i: Transportation Research Procedia, ISSN 2324-9935, E-ISSN 2352-1465, Vol. 15, s. 761-770Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Advanced Driver Assistance Systems (ADAS) offer the possibility of helping drivers to fulfill their driving tasks. Despite different encouraging factors, automated driving raise some concerns such as possible loss of situation awareness, overreliance on automation and system failure. This paper aims to investigate the effects of AV on driver’s behavior and traffic performance. A literature review was conducted to examine the AV effects on driver’s behavior. Findings from the literature survey reveal that conventional vehicles (CV), i.e. human driven, which are driving close to a platoon of AV with short THW, tend to reduce their THW and spend more time under their critical THW. Additionally, driving highly AV reduce situation awareness and can intensify driver drowsiness, exclusively in light traffic.

    In order to investigate the influences of AV on traffic performance, a simulation case study consisting of a 100% AV scenario and a 100% CV scenario was performed using microscopic traffic simulation. Outputs of this simulation study reveal that the positive effects of AV on roads are especially highlighted when the network is crowded (e.g. peak hours). This can definitely count as a constructive point for the future of road networks with higher demands. In details, average density of autobahn segment remarkably improved by 8.09% during p.m. peak hours in the AV scenario, while the average travel speed enhanced relatively by 8.48%. As a consequent, the average travel time improved by 9.00% in the AV scenario.

    The outcome of this study jointly with the previous driving simulator studies illustrates a successful practice of microscopic traffic simulation to investigate the effects of AV. However, further development of the microscopic traffic simulation models are required and further investigations of mixed traffic situation with AV and CV need to be conducted.

  • 2.
    Bergh, Torsten
    et al.
    Movea.
    Remgård, Mats
    Trafikverket.
    Carlsson, Arne
    Olstam, Johan
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Trafikanalys och logistik, TAL.
    Strömgren, Per
    Movea.
    2+1-roads Recent Swedish Capacity and Level-of-Service Experience2016Ingår i: Transportation Research Procedia, ISSN 2324-9935, E-ISSN 2352-1465, Vol. 15, s. 331-345Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The first Swedish 2+1 median barrier road was opened in 1998. The concept was to retrofit the standard existing two-lane 13 m paved width cross-section at 90 and 110 kph posted speed limit without widening. This design has one continuous lane in each direction, a middle lane changing direction every one to three kilometres with a median barrier separating the two traffic directions. Today over 2 700 km 2+1 median barrier roads are opened for traffic. AADT’s vary from some 3 000 to 20 000 with an average just below 10 000 nowadays normally with 100 kph.

    The concept has lately been enhanced also to cover the existing 9 m paved width cross-section. The design concept is the same from a driver’s viewpoint, one continuous lane in each direction with a middle lane changing direction and a separating median barrier. This is created by introducing a continuous median barrier and adding overtaking lanes within an overtaking strategy. The differences are the existence of 1+1-sections, less overtaking opportunities and a slightly more narrow cross-section. Some 15 projects are opened. The purpose of this paper is to summarize present knowledge on level-of-service issues as they are presented in Swedish design and assessment guidelines and to give an overview of field measurements and theoretical analytical and simulation studies supporting the recommendations.

  • 3.
    Paulsson, Alexander
    et al.
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Mobilitet, aktörer och planering, MAP.
    Hylander, Jens
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Mobilitet, aktörer och planering, MAP.
    Hrelja, Robert
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Mobilitet, aktörer och planering, MAP.
    What Culture does to Regional Governance: Collaboration and Negotiation in Public Transport Planning in Two Swedish Regions2016Ingår i: Transportation Research Procedia, ISSN 2324-9935, E-ISSN 2352-1465, Vol. 19, s. 147-150Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the context of public transportation, just as in many parts of society, the level of organizational complexity has increased over the last twenty years. Due to structural reforms and policy adjustments, responsibilities for the public transportation system in Sweden have become increasingly divided between a variety of public and private actors, thus fragmenting the organizational landscape. This development has led to an increased awareness of the need  to coordinate efforts in the public transport system. Not only does this involve coordination between private and public actors, it also involves coordination between public actors located at different vertical and horizontal scales in the government  structure. The literature on governance has developed as a means to theorize these shifts and changes. In particular, governance theories analyze changing  relations between public and private actors in providing common means and ends of societal development.

  • 4.
    Schippl, Jens
    et al.
    Karlsruhe Institute of Technology.
    Gudmundsson, Henrik
    DTU - Technical University of Denmark.
    Hedegaard Sørensen, Claus
    DTU - Technical University of Denmark.
    Anderton, Karen
    University of Oxford.
    Brand, Ralf
    Rupprecht Consult - Forschung & Beratung GmbH.
    Leiren, Merethe Dotterud
    Institute of Transport Economics.
    Reichenbach, Max
    Karlsruhe Institute of Technology.
    Different Pathways for Achieving Cleaner Urban Areas: A Roadmap towards the White Paper Goal for Urban Transport2016Ingår i: Transportation Research Procedia, ISSN 2324-9935, E-ISSN 2352-1465, Vol. 14, s. 2604-2613Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    The 2011 White Paper on Transport of the European Commission spells out a series of targets for 2030 and 2050. One of the 10 targets is explicitly related to urban transport and stipulates: ''Halve the use of 'conventionally fuelled' cars in urban transport by 2030; phase them out in cities by 2050. Achieve essentially CO2-free city logistics in major urban centres by 2030.'' With this paper we present and discuss a roadmap that deals with the question who needs to do what by when in order to reach the White Paper goal for urban transport. The ''stakeholder-driven'' roadmap was developed in the FP7 project TRANSFORuM. The paper will present the key findings and the suggested action steps identified in the roadmap. The paper will also exemplify three possible urban transformation pathways towards the urban target. This approach emerged from stakeholder consultations which highlighted the need to take into account the widely differing conditions among European cities.

  • 5.
    Strömgren, Per
    et al.
    Movea.
    Olstam, Johan
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Trafikanalys och logistik, TAL.
    A Model for Capacity Reduction at Roadwork Zone2016Ingår i: Transportation Research Procedia, ISSN 2324-9935, E-ISSN 2352-1465, Vol. 15, s. 245-256Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents an investigation of capacity reduction in connection with roadwork. The paper presents a state-of-the-art description on roadwork effects on capacity. The state-of-the art has been used to develop a model for estimation of capacity reduction at roadwork zone on Swedish roads. The model has partly been validated with empirical data from a full scale test at the freeway network in Gothenburg.

    The studies presented in the literature shows that capacity differs not only between different roadwork designs but also between roadwork with similar design. Thus, one can conclude that there is a high variation between the roadwork zone due to effects of surrounding elements, such as the type of work and external effects such as rain (which affects the capacity even under normal conditions). The differences that exist in the estimation of capacity for motorway sections next to a roadwork zone can be said to consist of four situation-specific variables:

    • the percentage of heavy vehicles
    • type of road
    • the width of the remaining lanes
    • diversion of traffic to the opposite carriageway

    The conclusion from the literature review is that the most important parameters that should be incorporated in a Swedish capacity manual for the operation and maintenance of roadwork are:

    • the proportion of heavy traffic
    • lane width, type of roadwork
    • number of closed lanes
    • closed road shoulder
    • proportion of commuter traffic
    • length of roadwork zone.

    The paper presents a comparison between the Dutch model for computation of capacity reduction and a composite model of reduction factors from Germany, USA and Denmark. The comparison show that the two models essentially gives the same results. Based on these results a new model was developed. In the developed model, the capacity for the remaining lane is calculated.

  • 6.
    Strömgren, Per
    et al.
    Kungliga Tekniska Högskolan.
    Olstam, Johan
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Trafikanalys och logistik, TAL.
    Tapani, Andreas
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Trafikanalys och logistik, TAL. Linköping Universitet.
    A Model for Traffic Simulation of Flared Rural Road Intersections2015Ingår i: Transportation Research Procedia, ISSN 2324-9935, E-ISSN 2352-1465, Vol. 6, s. 239-258Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a micro-simulation model that takes flared design of rural intersections into consideration. The intersection model is designed with input parameters that describe the geometric conditions of the flare. The behavior model includes both a traditional gap-acceptance sub-model and a passage model for modelling of vehicles’ possibility to pass other vehicles using the flare. The intersection model developed has been implemented in the traffic micro simulation model RuTSim. The gap-acceptance part of the model has been calibrated using data for stop and yield 3-way intersections. The validation was performed by using video recordings to calculate delay for the yield regulated intersection and time in queue and service time for the stop regulated intersection. The results from the validation simulations correspond well with the empirical validation data. The effect of the flare on delay has been studied by using 3 different intersection lay-outs and different levels of minor and major flow. The result shows that the delay is decreasing with increasing intersection radius.

  • 7.
    Tsanakas, Nikolaos
    et al.
    Linköpings Universitet.
    Ekström, Joakim
    Linköpings Universitet.
    Olstam, Johan
    Statens väg- och transportforskningsinstitut, Samhälle, miljö och transporter, SAMT, Trafikanalys och logistik, TAL.
    Reduction of errors when estimating emissions based on static traffic model outputs2017Ingår i: Transportation Research Procedia, ISSN 2324-9935, E-ISSN 2352-1465, Vol. 22, s. 440-449Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The rapid growth of traffic congestion has led to an increased level of emissions and energy consumption in urban areas. Well designed infrastructure and traffic controllers along with more efficient vehicles and policy measures are required to mitigate congestion and thus reduce transport emissions. In order to evaluate how changes in the traffic system affect energy use and emissions, traffic analysis tools are used together with emission models. In large urban areas emission models mainly rely on aggregated outputs from traffic models, such as the average link speed and flow. Static traffic models are commonly used to generate inputs for emission models, since they can efficiently be applied to larger areas with relatively low computational cost. However, in some cases their underlying assumptions can lead to inaccurate predictions of the traffic conditions and hence to unreliable emission estimates. The aim of this paper is to investigate and quantify the errors that static modeling introduces in emission estimation and subsequently considering the source of those errors, to suggest and evaluate possible solutions. The long analysis periods that are commonly used in static models, as well as the static models' inability to describe dynamic traffic flow phenomena can lead up to 40 % underestimation of the estimated emissions. In order to better estimate the total emissions, we propose the development of a post processing technique based on a quasi-dynamic approach, attempting to capture more of the excess emissions created by the temporal and spatial variations of traffic conditions

  • 8.
    Vierth, Inge
    et al.
    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.
    Effects of Longer Lorries and Freight Trains in an International Corridor between Sweden and Germany2014Ingår i: Transportation Research Procedia, ISSN 2324-9935, E-ISSN 2352-1465, Vol. 1, nr 1, s. 188-196Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effects of enabling the use of longer road vehicle combinations and/or longer trains in an intermodal freight corridor that extends from central Sweden to the Ruhr area in Germany are studied. Transports are designed based on the smallest vehicle dimensions in the transport chain, currently 18.75 m for trucks in Germany and 650 m for trains in Sweden. The question that is investigated is whether/how the transport system can be improved by using longer vehicles for road transports, rail transports or both. Ten scenarios are simulated with the help of the Swedish national freight model, Samgods. In Scenario Road 1 it is assumed that 25.25 m-long trucks are allowed on the entire road corridor (that also includes a ferry link). It is further assumed that the longer trucks can access the road corridor in Germany via terminals. In Scenario Rail 1, 750 m-long freight trains can be operated in the rail corridor that goes via Jutland/Denmark. In the combined Road 1 + Rail 1 scenario it is assumed that both longer trucks and longer trains can be used in the corridor. The effects on the freight flows, modal split, logistics costs and CO2 emissions are studied and rough socioeconomic analyses are carried out.

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