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  • 1.
    Allström, Andreas
    et al.
    Sweco.
    Kristoffersson, Ida
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics. Kungliga Tekniska Högskolan.
    Susilo, Yusak
    KTH.
    Smartphone based travel diary collection: Experiences from a field trial in Stockholm2017In: Transportation Research Procedia, Elsevier B.V. , 2017, Vol. 26, p. 32-38Conference paper (Refereed)
    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.

  • 2.
    Allström, Andreas
    et al.
    Trivector .
    Olstam, Johan
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics. Linköpings universitet, Kommunikations- och transportsystem.
    Thorsson, Tobias
    WSP .
    Analys av modeller för beräkning av framkomlighet i korsningar2008Report (Other academic)
  • 3.
    Anund, Anna
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kecklund, Göran
    Stockholm university, Stress research institute.
    Kircher, Albert
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Tapani, Andreas
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Åkerstedt, Torbjörn
    Karolinska institutet, Clinical neuroscience.
    The effects of driving situation on sleepiness indicators after sleep loss: A driving simulator study2009In: Industrial Health, ISSN 0019-8366, E-ISSN 1880-8026, Vol. 47, no 4, p. 393-401Article in journal (Refereed)
    Abstract [en]

    Almost all studies of sleepy driving are carried out in driving simulators and with monotonous road conditions (no interaction with other cars). The present study investigated indicators of sleepy driving in a more challenging scenario after a night awake. 17 participants drove a high fidelity moving base driving simulator experiment while sleepiness was monitored physiologically and behaviourally. Short periods of situations of free driving (no other vehicles) alternated with short periods of following another vehicle (car following) with and without the possibility to overtake. The result showed that a night of prior sleep loss increased sleepiness levels at the wheel (eye closure duration and lateral variability) compared to after a night of normal sleep. Blink duration while overtaking was significantly lower compared to the other situations, it was at the same level as after night sleep. Speed when passing a stopped school bus was not significantly affected by sleepiness. However the warning caused a more rapid reduction of speed. In conclusion, a moderately challenging driving contest did not affect sleepiness indicators, but a very challenging one did so (overtaking). This suggests that it is important to monitor the driving situation in field operational tests of sleepy driving.

  • 4.
    Anund, Anna
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Tapani, Andreas
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics. Linköpings universitet, Kommunikations- och transportsystem.
    Chalkia, Eleni
    Centre of Research and Technology Hellas/Hellenic Institute of Transport, Thessaloniki, Greece .
    Watch Out! Something Precious is Moving2011In: Infrastructure and Safety in a Collaborative World: Road Traffic Safety / [ed] E. Bekiaris, M. Wiethoff och E. Gaitanidou, Berlin Heidelberg: Springer Berlin/Heidelberg , 2011, 1, p. 233-242Chapter in book (Other academic)
    Abstract [en]

    One critical situation when a driver needs to have a high degree of awareness, to avoid critical situations or crashes, is when passing a school bus, stopped for boarding or de-boarding of children. With the help of an experiment in VTI’s moving base driving simulator, a scenario, using in-vehicle information before the bus was reached, was tested. The aim was to enhance drivers’ perception, in order to reduce the speed of vehicles passing by the stopped bus. Both alert and sleep deprived drivers were tested.

    The results showed a significant speed reduction thanks to the information given beforehand. Sleep deprivation did not seem to have an impact on speed reduction. This suggests that the warning signals are seen and followed, regardless the drivers’ state of alertness. Thus, it seems likely that this type of information may be useful as an Intelligent Transport System (ITS), to provide driver support about upcoming hazards. One step towards further research in this direction is performed within the EU project SAFEWAY2SCHOOL, the main objectives of which are presented at the end of this chapter.

  • 5.
    Aria, Erfan
    et al.
    Linköpings universitet.
    Olstam, Johan
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Schwietering, Christoph
    Schwietering Traffic Engineers, DE.
    Investigation of Automated Vehicle Effects on Driver's Behavior and Traffic Performance2016In: Transportation Research Procedia, ISSN 2324-9935, E-ISSN 2352-1465, Vol. 15, p. 761-770Article in journal (Refereed)
    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.

  • 6.
    Benz, Thomas
    et al.
    PTV AG, Germany.
    Gaitanidou, Evangelia
    Hellenic Institute of Transport, Greece.
    Spyropoulou, Ioanna
    National Technical University of Athens, Greece.
    Yannis, George
    National Technical University of Athens, Greece.
    Tapani, Andreas
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Modelling road traffic safety: the IN-SAFETY approach2006In: Proceedings of the 13th World Congress and Exhibition on Intelligent Transport Systems and Services, 2006Conference paper (Other academic)
    Abstract [en]

    This paper presents a model-based approach to road traffic safety developed within the EU funded project IN-SAFETY. Several existing models, both micro- and macro-models, will be adapted and used to assess safety related effects of ITS measures. Examples of such measures include but are not limited to ADAS and IVIS. While the micro-models will determine the individual vehicles' safety related behaviour, the macro-models will find out about the network wide aspects. Various models will be extended to cope with the ITS measures envisaged and then applied to relevant safety critical conditions. Major input will be available from the different test sites of the project, which are spread to cover the most significant aspects within the EU road environment.

  • 7.
    Benz, Thomas
    et al.
    PTV AG, Karlsruhe.
    Gaitanidou, Evangelia
    Centre for Research and Technology Hellas, Hellenic Institute of Transport (CERTH/HIT).
    Tapani, Andreas
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Toffolo, Silvana
    IVECO, ER&C, Torino, Italy .
    Yannis, George
    National Technical University of Athens (NTUA), Athens, Greece.
    Spyropoulou, Ioanna
    National Technical University of Athens (NTUA), Athens, Greece.
    Models on the Road2011In: Infrastructure and Safety in a Collaborative World / [ed] E. Bekiaris, M. Wiethoff och E. Gaitanidou, Berlin Heidelberg: Springer Berlin/Heidelberg, 2011, 1, p. 97-124Chapter in book (Other academic)
    Abstract [en]

    In this chapter, the application of macro and micro traffic simulation modelling for the needs of road safety assessment and planning is dealt. The overall concept of traffic simulation modelling regarding safety is presented, together with a series of macro and micro simulation models (namely RuTSim, S-Paramics, SATURN and VISSIM) that are widely used and have been specifically applied for the needs of IN-SAFETY project. ITS and ADAS related scenarios defined within IN-SAFETY, aiming to enhance the road safety level, have been tested through specially developed applications of these models and their results indicate the influence of the use of such technologies, as well as the effectiveness of the selected models in simulating and evaluating their effects. Future enhancement in the models will provide the possibility of further using them in the context of road safety and the involvement of innovative technologies.

  • 8.
    Bergh, Torsten
    et al.
    Movea.
    Remgård, Mats
    Trafikverket.
    Carlsson, Arne
    Olstam, Johan
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Strömgren, Per
    Movea.
    2+1-roads Recent Swedish Capacity and Level-of-Service Experience2016In: Transportation Research Procedia, ISSN 2324-9935, E-ISSN 2352-1465, Vol. 15, p. 331-345Article in journal (Refereed)
    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.

  • 9.
    Bergman, Astrid
    et al.
    Trivector Traffic.
    Olstam, Johan
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics. Linköpings universitet, Kommunikations- och transportsystem.
    Allström, Andreas
    Linköpings universitet, Tekniska högskolan.
    Analytical traffic models for roundabouts with pedestrian crossings2011In: Procedia - Social and Behavioral Sciences, ISSN 1877-0428, E-ISSN 1877-0428, Vol. 16, p. 697-708Article in journal (Refereed)
    Abstract [en]

    Roundabouts have become a more common type of intersection in Sweden over the last 30 years. In order to evaluate the roundabout level-of-service both analytical models and simulation models are being used. Analytical traffic models for intersections, such as the Swedish capacity model Capcal, has difficulties estimating the level-of-service of a roundabout if there are pedestrians and cyclists at crossings located close to the roundabout. It is well known that a crossing located after a roundabout exit can cause an up-stream blocking effect that affects the performance of the roundabout. But how the upstream blocking effect depends on the different flows of vehicles and pedestrians is not known. In this paper an existing analytical model by Rodegerdts and Blackwelder has been investigated and compared to simulations in VISSIM and measurements from Swedish roundabouts. The purpose of this investigation is to examine if the model by Rodegerdts and Blackwelder is suitable for implementing into existing analytical models such as Capcal. The results show that the model by Rodegerdts and Blackwelder can estimate if a capacity loss will occur, but the magnitude of this loss is more difficult to evaluate. The conclusion and recommendation is that the model by Rodegerdts and Blackwelder should be implemented into the Swedish capacity model Capcal. The model by Rodegerdts and Blackwelder is to be used as a warning system if the results in Capcal are too uncertain to use for analysis of the roundabout performance.

  • 10.
    Bergquist, Markus
    et al.
    Trafikverket/Academic Work.
    Bernhardsson, Viktor
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Rosklint, Emma
    Trafikverket.
    Representation of the Swedish transport and logistics system in Samgods v. 1.1.2016Report (Other academic)
    Abstract [en]

    The national model for freight transportation in Sweden is called Samgods. The purpose of the model is to provide a tool for forecasting and planning of the transport system. Samgods can be used in policy analysis such as studying the effects of a tax change or a change in transport regulation etc. The aim of this report is to give an overview of how the Swedish transport and logistics system is represented in the Samgods model. Samgods consists of several parts, where the logistics module is the core of the model system. This report describes the setup data needed to run version 1.1 of the Samgods model.

    The 35 commodity groups used in the model are based on the 24 groups in the European NST/R- nomenclature. Some commodities are further divided due to their importance for Swedish freight transport and varying logistic properties. Transport demand is described with commodity specific demand matrices for 464 administrative zones inside and outside Sweden. The commodity specific P, C or W zones are split into sub-cells that include firms. The method used to generate the firm to firm flows is to divide the firms at the origin zone and destination zone into three categories according to size.

    A range of vehicle and vessel types are used to reflect scale advantages in transporting operations, including loading and unloading. The Samgods model uses six vehicle types for road, 10 for rail, 22 for sea and one for air. In total, 98 pre-defined transport chains are used.

    Infrastructure networks are used to generate the level of service (LOS)-matrix data for each vehicle/vessel type providing transport time and, distance and network related infrastructure charges. The logistics costs consist of transport costs (vehicle type specific link costs and node costs) and non-transport costs (commodity specific order costs, storage costs and capital costs in inventory as well as capital costs in transit). For each commodity it is assumed that either the overall logistics costs are optimized or the transport costs are minimized. The model generates a huge amount of output at different levels. All the output files generated are described in the last chapter of this report.

  • 11.
    Bernhardsson, Viktor
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Genomlysning av VQ-samband för tvåfältsvägar: Metodförslag till förbättrad klassificering2018Report (Other academic)
    Abstract [sv]

    Trafikverkets hastighetsflödessamband (VQ-samband) redovisar reshastighet på väglänkar för fordonstyperna personbil (pb), lastbil/buss utan släp (lbu) och lastbilar med släp (lbs) som funktion av totalt trafikflöde. VQ-sambanden delas in i olika klasser baserat på vägtyp, hastighetsgräns etc. och sambanden uppdateras kontinuerligt (vanligtvis i fyraårsintervaller) baserat på nya mätdata.

    Vid den senaste revideringen (2017) visade det sig vara svårt att utifrån tillgänglig information i Nationella vägdatabasen (NVDB) bestämma lämplig VQ-klass. Detta eftersom data i NVDB huvudsak beskriver hur vägen ser ut och inte hur den fungerar ur ett trafikföringsperspektiv. För vissa vägtyper är den nuvarande klassindelningen inte längre lämplig. Exempelvis, för tvåfältsvägar tillämpar Trafikverket idag en uppdelning baserat på vägbredd, men skillnaden i hastighet mellan olika vägbredder verkar mer troligt bero på vilken typ av trafik (kortväga/långväga) som trafikerar breda respektive normalbreda vägar.

    Syftet med detta uppdrag var att genomföra en genomlysning av nuvarande indelning av vägklasser och föreslå en ny vägklassindelning för tvåfältsvägar. I nuläget tillämpas följande förklaringsvariabler för hastighetssamband på tvåfältsvägar:

    • Hastighetsgräns
    • Vägbredd
    • Siktklass

    Först genomfördes en översyn av lämpliga datakällor att inkludera vid bedömning av lämpliga förklaringsvariabler. Vid den senaste revideringen av VQ-sambanden tillämpades enbart data från Trafikverkets trafikmätningssystem (TMS) som synkats mot NVDB. Kompletterande mätningar i form av Trafikverkets mätningar för beräkning av hastighetsindex samt synkning mot databasen Pavement Management Systems (PMSv3) bör kunna tillföra relevant information.

    Baserat på erfarenhet och tillgängliga datakällor, gjordes en översyn av vilka faktorer som antas påverka trafikföringen på tvåfältsvägar. En bruttolista med faktorer identifierades, vilka senare användes som grund för att skapa en enkät som distribuerades till en referensgrupp, beståendes av sakkunniga inom branschen. Referensgruppen bedömde vilka faktorer som ansågs påverka trafikföringen på tvåfältsvägar i störst utsträckning, samt bidrog med direkta förslag till lämpliga förklaringsvariabler.Baserat på resultaten från enkätundersökningen identifierades ett antal förslag på lämpliga förklaringsvariabler, samt hur de skulle kunna extraheras från tillgängliga data. Följande förklaringsvariabler föreslås för hastighetsflödessamband på tvåfältsvägar:

    • Hastighetsgräns
    • Linjeföring
    • Trafiktyp
    • Vägutformning
    • Trafiksammansättning

    Förslagsvis utvärderas ett antal givna kombinationer av dessa förklaringsvariabler baserat på spridningen i datamaterialet för den aktuella grupperingen av förklaringsvariabler. Regressionsanalys kan tillämpas för att bedöma lämplig gruppering.

  • 12.
    Bernhardsson, Viktor
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Trafiksimulering av E20 Ribbingsberg–Vara: En simuleringsstudie av framkomlighet för en mötesfri utformning av E202017Report (Other academic)
    Abstract [en]

    The part of road E20 between Ribbingsberg and Vara in Sweden will be converted from a two-lane rural road with speed limit 80 kilometers per hour into an oncoming separated highway with speed limit 100 kilometer per hour. The suggested design of the oncoming separated highway includes sections of 1+1 and 2+2 lanes with varying lengths between 1.6 and 3.2 kilometers. Due to the current high level of traffic demand in combination with high levels of trucks, the traffic performance at the suggested design could be questioned. In order to evaluate traffic performance, a traffic simulation study has been performed for the peak hour during a typical weekday. The study includes three different scenarios of traffic demand, representing levels of year 2015, 2025 and 2045. Simulations are performed using the microscopic simulation model RuTSim (Rural road Traffic Simulator), developed by VTI and customized for rural traffic. The model is calibrated using measurements from the actual road stretch in combination with data from the adjacent oncoming separated highway with speed limit 100 kilometers per hour between Vara and Skara. Simulation of year 2045 generates average speed for cars of 94 kilometers per hour. Sensitivity analysis of limited overtaking willingness results in average speed as minimum 92 kilometers per hour.

    This means that the traffic performance fulfills the condition according to Trafikverkets former requirement that the average speed for cars should not be less than 10 kilometers per hour below the speed limit (100 kilometer per hour). The share of constrained vehicles also supports the conclusion of a design with satisfying traffic performance. It should though be mentioned that the lengths of the twolane segments within the suggested design exceeds the recommendations according to Trafikverket

  • 13.
    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.

  • 14.
    Bång, Karl-Lennart
    et al.
    Kungliga Tekniska Högskolan.
    Olstam, Johan
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics. Linköpings universitet, Kommunikations- och transportsystem.
    Köhler, Joakim
    WSP.
    Wahlstedt, Johan
    Kungliga Tekniska Högskolan.
    Andersson, Jonas
    Tyrens.
    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.

  • 15.
    Börjesson, Maria
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics. KTH.
    Kristoffersson, Ida
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    The Swedish congestion charges: Ten years on2018In: Transportation Research Part A: Policy and Practice, ISSN 0965-8564, E-ISSN 1879-2375, Vol. 107, p. 35-51Article in journal (Refereed)
    Abstract [en]

    Time-of-day dependent cordon-based congestion charging systems were introduced in Stockholm in 2006, and in Gothenburg in 2013. The Stockholm system was significantly extended in 2016, and the peak charge has been increased in the two cities. This paper analyses the effects of the first decade with the Swedish congestion charges, specifically effects of the system updates, and draws policy lessons for the years to come. Should we introduce congestion charges in more cities? Should we extend the systems that we have? We synthesize previous research findings and focus on the long-term effects that have varied over time including the recent years: the price elasticities on the traffic volume across the cordon, the revenue and system operating cost, the public and political support, and consequences for the transport planning process. We also explore the effects on peak and off-peak, and different types of traffic (trucks, company cars and private passenger cars), because of access to novel data that make this analysis possible. We find that the price elasticities have increased over time in Stockholm, but decreased in Gothenburg. We find that the public support increased in the two cities after their introduction until the systems were revised; since then, the public support has declined in both cities. We find that the price elasticity was substantially lower when the charging levels were increased, and when the Stockholm system was extended, than when the charges were first introduced, a likely reason being that the most price-sensitive traffic was already priced off-the road at the introduction.

  • 16.
    Cacciabue, Pietro Carlo
    et al.
    KITE Solutions.
    Enjalbert, Simon
    Univ. Lille Nord de France.
    Söderberg, Håkan
    Chalmers University of Technology.
    Tapani, Andreas
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics. Linköpings universitet, Kommunikations- och transportsystem.
    Unified Driver Model simulation and its application to the automotive, rail and maritime domains2013In: Transportation Research Part F: Traffic Psychology and Behaviour, ISSN 1369-8478, E-ISSN 1873-5517, Vol. 21, p. 315-327Article in journal (Refereed)
    Abstract [en]

    This paper describes the implementation of a model of a driver into a computerised numerical simulation. The model is developed to capture the essential characteristics and common aspects of cognition and behaviour of a human being in control of a “vehicle” in different surface transport systems, namely trains, cars and ships. The main functions of the simulation are discussed as well as the experiments carried out in different types of driving simulators to support the estimation of the parameters utilised in the numerical simulation. The validation processes carried out in the rail and maritime domains are also discussed together with a critical review of capacities and limitations of the proposed approach.

  • 17.
    Camén, Carolina
    et al.
    Karlstad Universitet.
    Lidestam, Helene
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics. Linköping Universitet.
    Dominating factors contributing to the high(er) costs for public bus transports in Sweden2016In: Research in Transportation Economics, ISSN 0739-8859, E-ISSN 1875-7979, Vol. 59, p. 292-296Article in journal (Refereed)
    Abstract [en]

    The purpose of this study is to deepen the understanding of what are the underlying reasons for the increasing cost of public transport in general and bus services in particular in a Swedish context. Data were collected through in-depth interviews with managers at the bus operators as well as the authority organizations. This paper contributes by identifying nine categories that can be the dominating factors behind the increasing costs of public bus services in Sweden.

    The identified categories of cost drivers are; of traffic appearance (peak times), greening of buses, age requirements, the contract period, the accessibility customization, special requirements on buses, collective agreements (working time regulation), tendering and contracting process, and finally, counterproductive political governance. It can be concluded that many of the cost drivers originate from the circumstances of the process of public procurement, such as different demands for different regions in Sweden as well as the trade-off between the bus operators' wishes for higher flexibility in the contracts and the traffic authorities' fear of more risks and thereby higher bids in the end.

  • 18.
    Carlson, Annelie
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Björketun, Urban
    Swedish National Road and Transport Research Institute, Traffic and road users, Traffic safety, society and road-user.
    Hammarström, Ulf
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Utveckling av VTI:s modell för beräkning av trafikarbete på svenska vägar2013Report (Other academic)
    Abstract [en]

    Each year, VTI delivers a description of both a historical description and a prognosis of the annual vehicle mileage using a forecast model. Based on the results from this model a simplified description is made of the future traffic in HBEFA, which is the basis for the annual calculation of traffic emissions. The purpose of this project was to undertake a general revision of the method, both historical and future, in the forecast model. The assessment shows, for example, that a computational model can continually evolve and improve. Recent data have become available through the meter readings for mileage and better data are now available to take into account heavy trucks used for overseas shipments. A function adaptation of mileage as a function of vehicle age shows a good agreement with the measured driving distances for vehicles up to and including about 25 to 30 years of age. A sensitivity analysis of making various assumptions regarding the mileage and age distribution shows the effect on the amount of fuel consumption and regulated emissions for different categories of vehicles.

  • 19.
    Carlson, Annelie
    et al.
    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.
    Hammarström, Ulf
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Utvärdering PHEM-modellen: En förstudie2013Report (Other academic)
    Abstract [en]

    The Swedish Transport Administration has stated that there is a need to develop the use of micro simulation models of fuel use and emissions of traffic that are used for transport planning. The aim of the project is to perform an evaluation of PHEM model to investigate conditions, opportunities and barriers to use it in transport planning. The following aspects have been assessed: License agreements, costs, rights, property issues; User friendliness; Content and calculation capabilities; Adjustment and development possibilities; Validation. Furthermore, simulation tests have been performed where fuel consumption and emissions of nitrogen oxide, nitrogen monoxide, carbon monoxide, hydrocarbons, particulate mass and particle number has been calculated for roads with different road classes and for additional emissions and fuel use due to a vehicle stop. PHEM model is found to be relatively user-friendly, and with great opportunities to customize calculations. This makes the model complex, therefore it is recommended to start using PHEM with a short introductory course, even for used modellers. A conclusion of the evaluation is a recommendation to use PHEM for transport modelling. The database underlying the engine maps is constantly updated leading to more reliable emission calculations. The possibility to get a greater coherence in the calculations of the exhaust emissions of the different models that the Transport Administration advocate is also improved, which is a positive development. There are, also, some development possibilities that should be considered.

  • 20.
    Carlsson, Arne
    et al.
    Swedish National Road and Transport Research Institute.
    Tapani, Andreas
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Rural Highway Design Analysis Through Traffic Micro-Simulation2006In: Proceedings of the 5th International Symposium on Highway Capacity and Quality of Service, Tokyo: JSTE , 2006, p. 249-258Conference paper (Refereed)
    Abstract [en]

    In Sweden, rural roads with separated oncoming lanes are becomingincreasingly important due to their superior safety properties.The level-of-service of such roads may however be reduced since traffic is restricted by the barrier between the oncoming lanes.This level-of-service impact can be evaluated through traffic microsimulation.Such simulation based assessments of rural highways require simulation models capable of modeling rural road traffic.This paper presents a simulation study of different rural road designs with separated oncoming lanes using a rural road traffic simulationmodel. The presentation illustrates the use of simulationfor rural highways and the result of the study indicates that oncominglane separation is a competitive alternative despite slightlevel-of-service reductions compared to undivided two-lane highways.

  • 21.
    Carlsson, Arne
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Enviroment and traffic analysis.
    Wiklund, Mats
    Trafikanalys.
    Olstam, Johan
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Tapani, Andreas
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Metod för beräkning av fördröjningar på vägavsnitt utan omkörningsmöjlighet2013Report (Other academic)
    Abstract [en]

    This VTI report presents a method for calculating expected queue length and travel time delay on one lane road sections without overtaking possibilities. The method was developed 2001 and presented in a working paper. The background for the model development was that the Swedish Road Administration (now the Swedish Transport Administration) planned to build so called 1+1 roads, i.e. roads with longer sections without overtaking possibilities. The method developed has later on also shown to be valuable for level of service calculations of 2+1 roads with varying share of two lane sections and for developing speed-flow relationships for the Administration’s ”Effect calculations for road facilities”. The method uses section length, traffic flow, average speed and standard deviation as input. The method is divided with respect to calculation of effects due to single slowrunning vehicles and effects at “normal” speed distribution. Since no data were available when the model was developed, the model results were instead compared to traffic simulations with the microscopic traffic simulation model AIMSUN. The results show a good correlation but the analytical model gives in general approximately 1.2 per cent lower travel time delay. The differences can probably partly be explained by the stochastic parts of the simulation model. One should also remember that neither the analytical model nor the simulation model has been calibrated and validated with real data for this type of roads. Thus, the differences between the models do not necessary imply that the analytical model is the one deviating from reality.

  • 22.
    Dukic, Tania
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Ahlström, Christer
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Björketun, Urban
    Swedish National Road and Transport Research Institute, Traffic and road users, Traffic safety, society and road-user.
    Kettwich, Carmen
    Karlsruhe Institute of Technology.
    Yahya, Mohammad Reza
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Patten, Christopher
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Tapani, Andreas
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Vadeby, Anna
    Swedish National Road and Transport Research Institute, Traffic and road users, Traffic safety, society and road-user.
    Inverkan av elektroniska reklamskyltar på trafiksäkerhet: en studie på E4 i Stockholm2011Report (Other academic)
    Abstract [en]

    The present report presents four studies that were conducted with the aim to evaluate how electronic billboards (ERS) affect traffic safety. Study 1 is a literature review to examine how billboards impact road safety. The conclusions from the review showed that animated pictures and the location of the billboards have a major impact on driver behaviour as well as that darkness and adverse weather conditions can create glare which makes driving difficult especially for older drivers.

    The second and third studies compared the speed and the number of accidents before and after the installation of the billboards. Neither difference in traffic volume nor in average speed could be demonstrated. There was nothing in the studied accidents to suggest that the accident was affected by a billboard.

    The fourth sub-study is a field study investigating 41 drivers (driving and visual behaviour) on the E4 as they pass the billboards. Results showed several cases of visual distraction. The results also show a negative attitude to the billboards for a majority of the drivers.

    In summary, no effects from the billboards on traffic safety could be showed at the macro level. However, the effects of visual distraction must be taken into consideration and investigated further before deciding whether billboards will be implemented on Swedish roads.

  • 23.
    Elyasi-Pour, Roya
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics. Linköpings universitet.
    Driving behavior model in a simulation based evaluation approach for Look Ahead Cruise Control2014Conference paper (Other academic)
  • 24.
    Elyasi-Pour, Roya
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics. Linköpings universitet, Kommunikations- och transportsystem.
    Olstam, Johan
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics. Linköpings universitet, Kommunikations- och transportsystem.
    Utvärdering av förarstödsystem baserat på sammankoppling av trafiksimulering och fordonsimulering2014Conference paper (Other academic)
  • 25.
    Eriksson, Jenny
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafiksäkerhet och trafiksystem, TST.
    Henriksson, Per
    Swedish National Road and Transport Research Institute, Society, environment and transport, Mobility, actors and planning processes.
    Rogerson, Sara
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Sörensen, Gunilla
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafiksäkerhet och trafiksystem, TST.
    Silvano, Ary P.
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafiksäkerhet och trafiksystem, TST.
    Nilsson, Annika
    Trivector.
    Wahl, Charlotte
    Sweco.
    Ullberg, Martin
    Sweco.
    Adell, Emelie
    Trivector.
    Intressent- och behovsanalys för resvaneundersökningar: resultat från intervjuer och enkätundersökning2017Report (Other academic)
    Abstract [en]

    In Sweden, national travel surveys are regularly carried out by Transport Analysis, a governmental agency. However, in the last decade travel survey studies have suffered with problems such as high rate of non-response, coverage, costs and reporting burden. Therefore, this project is underway aimed at investigating and proposing new methods for data collection on people’s mobility. The project is divided into five deliverables (work packages – WP), of which this report is the second one (WP2). The purpose is to carry out an analysis of stakeholders’ needs regarding future requirements of travel surveys. This includes identifying the questions that travel surveys can answer.

    Telephone interviews have been conducted with 20 stakeholder representatives and internet-based questionnaires were sent to 142 respondents (response 81 persons, response rate 57 percent). The stakeholders’ representatives were classified into three types of organizations: public sector, research organizations and other actors. Based on their own experience, an analysis has been conducted regarding what is requested from the national travel survey. The analysis show that key aspects of today’s and tomorrow’s travel survey users include (i) mode choice, (ii) trip purpose, (iii) how travel behavior changes over time, and (iv) how different groups travel. To be able to answer these questions, both individual and travel information are required.

  • 26.
    Eriksson, Jenny
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Traffic Safety and Traffic System.
    Liu, Chengxi
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Forward, Sonja
    Swedish National Road and Transport Research Institute, Society, environment and transport, Mobility, actors and planning processes.
    Forsman, Åsa
    Swedish National Road and Transport Research Institute, Traffic and road users, Traffic Safety and Traffic System.
    Niska, Anna
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Tapani, Andreas
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Wallén Warner, Henriette
    Swedish National Road and Transport Research Institute, Society, environment and transport, Mobility, actors and planning processes.
    Säkerhetseffekten av ökat cyklande: kartläggning av nuläget för att planera för framtiden2017Report (Other academic)
    Abstract [en]

    During the last decades, cycling has been highlighted as a travel mode with many positive qualities. The documents of Swedish national strategy reveal a trend of an increased cycling. At the same time, it is important that the safety of cyclists must be improved so that an increased cycling does not contribute to more injuries and fatalities in accidents. To cope with the increased cycling without compromising the safety, there is fore example, a need for better understanding of the relationship between the cycling flow and the injuries in various traffic environments.

    In this project, three different studies were carried out to understand how the trend of cycling changes over time and how cyclists' injury risk is influenced by the cycling flow and the traffic environment. In the first study, a travel demand model has been developed that includes both mode choice and destination choice for cycling. In the second study, models for cyclists’ injury risks have been developed for different types of accidents and traffic environments. In the third study, interactions between different road users have been observed, to study how these are affected by the level of bicycle flow. Overall, the studies in this project have shown that bicycle flow is an important factor influencing cyclists’ accident risks. Higher bicycle flow corresponds to fewer interactions per cyclist and a lower risk of injury in a single bicycle accident as well as in a collision accident with motorised vehicles. We have also been able to demonstrate that it is possible to model travel choices and destination choice of cyclists and to develop models that describe cyclists’ injury risk. However, to provide better estimates, data with better quality are necessary for the model inputs, especially when it comes to the cycling and the description of cycling infrastructure.

  • 27.
    Finnsgård, Christian
    et al.
    SSPA Sweden AB.
    Kalantari, Joakim
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Raza, Zeeshan
    University of Gothenburg.
    Roso, Violeta
    Chalmers University of Technology.
    Woxenius, Johan
    University of Gothenburg.
    Swedish shippers’ strategies for coping with slow-steaming in deep sea container shipping2018In: Journal of Shipping and Trade, ISSN 2364-4575, Vol. 3, no 8Article in journal (Refereed)
    Abstract [en]

    When container shipping lines experience over-capacity and high fuel costs, they typically respond by decreasing sailing speeds and, consequently, increasing transport time. Most of the literature on this phenomenon, often referred to as slow-steaming, takes the perspective of the shipping lines addressing technical, operational and financial effects, or a society perspective focusing on lower emissions and energy use. Few studies investigate the effects on the demand side of the market for container liner shipping. Hence, the aim of this study is to elaborate on the logistics consequences of slow-steaming, particularly the strategies that Swedish shippers purchasing deep sea container transport services employ to mitigate the effects of slow-steaming. Workshops and semi-structured interviews revealed that shippers felt they had little or no impact on sailing schedules and were more or less subject to container shipping lines’ decisions. The effects of slow-steaming were obviously most severe for firms with complex supply chains, where intermediate products are sent back and forth between production stages on different continents. The shippers developed a set of strategies to cope with the low punctuality of containerised shipping, and these were categorised in the domains of transfer-the-problem, transport, sourcing and distribution, logistics and manufacturing, and product design. All firms applied changes in the transport domain, although the lack of service segmentation limited the effects of the strategy. Most measures were applied by two firms, whereas only one firm changed the product design.

  • 28.
    Flötteröd, Gunnar
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    DTA simulation with reduced number of iterations2018Conference paper (Refereed)
    Abstract [en]

    An iterated (day-to-day) dynamic traffic assignment (DTA) is considered. In each iteration, a certain fraction of the totaltravel demand adjusts its travel pattern before the entire demand is loaded onto the (congested) network. It is assumed that thedemand is composed of at least two commodities that exhibit non-identical travel behaviors. The demand changes from oneDTA iteration to the next can then be decomposed into two components: (i)demand exchangesbetween commodities, whichdo not affect the total (aggregate over all commodities) demand pattern, and (ii)demand shifts, which do affect the total demandpattern. Given that there are many (day-to-day) sequences of demand and congestion patterns that lead to the same stationaryassignment, the approach taken here is to minimize congestion variability along this path by favoring, to the extent possible,demand exchangesoverdemand shifts. The underlying intuition is that the resulting reduction in congestion variability andconsequently better predictability of travel times leads to a faster and/or more stable convergence of the assignment.

    The selection of replanning rates in general-purpose DTA simulation packages has, due to the limited tractability of suchsystems, received limited attention in the literature. In deterministic settings, flow averaging schemes according to (variantsof) the method of successive averages are often considered (Liu et al., 2007). In stochastic process assignment, constantreplanning rates may be preferred because these can lead to unique stationary process distributions (Watling and Hazelton,2003). The possibly interesting twist of the approach described here is that it (i) leaves the choice of a global replanningrate (being identical for all commodities) to any available algorithm or expert and then (ii) accelerates the convergence of thesimulation process by deriving commodity-specific replanning rates. Lu and Mahmassani (2007) and later Lu et al. (2009)pursue the same line of thinking but make more specific modeling assumptions (a route swapping assignment that aims atattaining a deterministic user equilibrium) than what is assumed in the subsequently described method.

  • 29.
    Flötteröd, Gunnar
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Dynamic Traffic Signal Control, Dynamic Queueing, and Dynamic Route Choice2018In: Smart Transportation: Proceedings of The 7th International Symposium on Dynamic Traffic Assignment 6-8 June 2018 Hong Kong / [ed] W.Y. Szeto, Hong K. Lo and S.C. Wong, 2018Conference paper (Refereed)
  • 30.
    Forsman, Åsa
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Traffic safety, society and road-user.
    Vadeby, Anna
    Swedish National Road and Transport Research Institute, Traffic and road users, Traffic safety, society and road-user.
    Yahya, Mohammad Reza
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Enjalbert, Simon
    UNIVAL.
    Cassani, Mirella
    KITE.
    Amantini, Aladino
    KITE.
    Lai, Frank
    University of Leeds.
    Kecklund, Lena
    MTO Säkerhet AB.
    Arvidsson, Marcus
    MTO Säkerhet AB.
    Results from the analysis and input to the development and validation of the statistical models2011Report (Other academic)
    Abstract [en]

    The aim of Deliverable 5.1 of the ITERATE project is to present results of analyses made of the data collected in the ITERATE WP4 driving simulator experiments. The ITERATE WP4 driving simulator experiments consisted of train and car driving experiments carried out on a portable car/train driving simulator platform and in full scale car and train driving simulators. The analyses conducted and presented in this deliverable consist of hypothesis testing, cluster analysis and development of a procedure for estimation of parameters of relationships in the WP6 UMD simulation model. Findings from the analyses show that country was found to be an important factor in both the car and train driving experiment. Significant effects of the factor workload were also established in many of the events analysed. The conclusion of comparisons between the data collected in the portable and full scale simulators is that the ITERATE portable driving simulator platform is a suitable tool to studying underlying factors controlling driver behaviour at least for the car diving. However, there were differences between the portable and full scale train simulators. These differences have to be considered in later stages of the project. The next step within the ITERATE project is to estimate relevant relationships in the WP6 UMD simulation model based on the findings of the analyses presented in this deliverable. The analyses presented will also be important as inspiration for other studies outside of the present project with the ITERATE driving simulator dataset as an important source of data.

  • 31.
    Grumert, Ellen
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Cooperative systems: an overview2011Report (Other academic)
    Abstract [en]

    The objective of this report is to give an introduction to the subject of cooperative systems and an overview of projects related to cooperative systems. Issues related to cooperative systems are also discussed in the report. Two areas of great importance for cooperative systems are the standardization process of cooperative systems in Europe and the communication frequency used for cooperative systems. These two subjects are therefore discussed in more detail in the report. The objective of this report is to give an introduction to the subject of cooperative systems and an overview of projects related to cooperative systems. Issues related to cooperative systems are also discussed in the report. Two areas of great importance for cooperative systems are the standardization process of cooperative systems in Europe and the communication frequency used for cooperative systems. These two subjects are therefore discussed in more detail in the report.

    The report has been focusing on cooperative systems, which is a part of the wider concept Intelligent Transport Systems (ITS). The 'traditional' Intelligent Transport Systems use technology, inside or outside of the vehicle, to give the driver some kind of information. The driver gets the opportunity to act upon the given information. Along with the increased amount of new technology the use of information and communication in the transport area has increased. Today cooperative systems are well-known in the transport area. The idea is to extend the more traditional Intelligent Transport Systems and build systems that are able to communicate with each other. These systems could be located inside the vehicle or as a road-side unit outside of the vehicle. The benefit with cooperative systems is the ability to send and receive real-time information and to use this information in order to increase safety, efficiency and environmental impacts on the roads.

  • 32.
    Grumert, Ellen
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics. Linköpings universitet, Kommunikations- och transportsystem.
    Cooperative Variable Speed Limit Systems: Modeling and Evaluation using Microscopic Traffic Simulation2014Licentiate thesis, monograph (Other academic)
    Abstract [en]

    During the last decades the road traffic has increased tremendously leading to congestion, safety issues and increased environmental impacts. As a result, many countries are continuously trying to find improvements and new solutions to solve these issues. One way of improving the traffic conditions is by the use of so called intelligent transport systems, where information and communication technologies are being used for traffic management and control. One such system commonly used for traffic management purposes are variable speed limit systems. These systems are making use of signs to show speed limits adjusted to the prevailing road or traffic conditions. The rapid development in telecommunication technologies has enabled communication between vehicles, and between vehicles and the infrastructure, so called cooperative systems. This opens up for  the possibility to further improve the performance of a standard variable speed limit system by adding cooperative system features.

    The overall aim of this thesis is to investigate the potential benefits of incorporating infrastructure to vehicle communication and autonomous control to an existing variable speed limit system. We show how such a cooperative variable speed limit system can be modeled and evaluated by the use of microscopic traffic simulation. Results from the evaluation indicate increased flow harmonization in terms of narrowing of the acceleration rate distribution and reduced exhaust emissions.

    Further, we compare four control algorithms for deciding on speed limits in variable speed limit systems. Differences in the resulting traffic performance between the control algorithms are quantified by the use of microscopic traffic simulation. It is concluded that the dened objective for the algorithms have a decisive influence on the effects of the variable speed limit system.

    The results from this thesis are useful for further development of variable speed limit systems, both with respect to incorporating cooperative features and by improving the speed setting control algorithms.

  • 33.
    Grumert, Ellen
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics. Linköping University.
    Evaluation of Four Control Algorithms Used in Variable Speed Limit Systems2016In: TRB 95th Annual Meeting Compendium of Papers, Washington, 2016, article id 16-2880Conference paper (Refereed)
    Abstract [en]

    Control algorithms used for deciding on the speed limits in variable speed limit systems are crucial for the performance of the system. Today, many of the control algorithms used are based on fixed thresholds in speed and/or flow for lowering and increasing the speed limit. The algorithms are not necessarily reflecting the conditions on the road, which might lead to low traffic efficiency. Our hypothesis is that by use of a simple and efficient control algorithm that is better in reflecting the conditions on the road, both traffic efficiency and traffic safety could be increased. In this study, four control algorithms used in variable speed limit systems, and fulfilling the above criteria, are evealuted through microscopic traffic simulation. Performance indicators related to traffic safety, traffic efficiency and environmental impacts are presented. The results show that the design of, and the objective with, the control algorithm have a great impact on the performance. Moreover, the time needed for incident detection, the duration of and the size of the speed limit reduction and the location of the congestion are of importance for the performance of the control algorithms. These results will be of importance for design and implementation of future efficient variable speed limit systems.

  • 34.
    Grumert, Ellen
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics. Linköpings universitet, Kommunikations- och transportsystem.
    Ma, Xiaoliang
    Kungliga tekniska högskolan (KTH).
    Tapani, Andreas
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics. Linköpings universitet.
    Analysis of a cooperative variable speed limit system using microscopic traffic simulation2015In: Transportation Research Part C: Emerging Technologies, ISSN 0968-090X, E-ISSN 1879-2359, Vol. 52, p. 173-186Article in journal (Refereed)
    Abstract [en]

    Variable speed limit systems where variable message signs are used to show speed limits adjusted to the prevailing road or traffic conditions are installed on motorways in many countries. The objectives of variable speed limit system installations are often to decrease the number of accidents and to increase traffic efficiency. Currently, there is an interest in exploring the potential of cooperative intelligent transport systems including communication between vehicles and/or vehicles and the infrastructure. In this paper, we study the potential benefits of introducing infrastructure to vehicle communication, autonomous vehicle control and individualized speed limits in variable speed limit systems. We do this by proposing a cooperative variable speed limit system as an extension of an existing variable speed limit system. In the proposed system, communication between the infrastructure and the vehicles is used to transmit variable speed limits to upstream vehicles before the variable message signs become visible to the drivers. The system is evaluated by the means of microscopic traffic simulation. Traffic efficiency and environmental effects are considered in the analysis. The results of the study show benefits of the infrastructure to vehicle communication, autonomous vehicle control and individualized speed limits for variable speed limit systems in the form of lower acceleration rates and thereby harmonized traffic flow and reduced exhaust emissions.

  • 35.
    Grumert, Ellen
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Tapani, Andreas
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Impacts of a Cooperative Variable Speed Limit System2012In: Procedia - Social and Behavioral Sciences, ISSN 1877-0428, E-ISSN 1877-0428, Vol. 43, p. 595-606Article in journal (Refereed)
    Abstract [en]

    Variable Speed Limit Systems (VSLS) where variable message signs show speed limits based on, for example,traffic volume or road conditions exists on motorwaysin many countries. The purpose of the VSLS is to decrease the number of accidents and to increase traffic efficiency. Cooperative systems are a type of intelligent transport system that has received increasing interest lately. The central part of a cooperative system is communication between vehicles and/or vehicles and the infrastructure. In this paper, a cooperative systems extension of a VSLS is proposed and evaluated by means of traffic simulation. By adding cooperative systems functionality to an existing VSLS there is a potential for further increase in traffic efficiency and also to reduce the environmental impacts of the traffic on the road. In the proposed cooperative VSLS, communication between the vehicles and the infrastructure is made available via a roadside unit communicating the speed limits to vehicles upstream on the road. The results of the study show that the cooperative VSLS has a potential to contribute to flow harmonization and to reduce environmental impacts.

  • 36.
    Grumert, Ellen
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Tapani, Andreas
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics. Linköpings universitet, Kommunikations- och transportsystem.
    Microscopic traffic simulation for evaluation of a cooperative variable speed limit system2013In: 1st SUMO User Conference 2013. Proceedings, Berichte aus dem DLR-Institut für Verkehrssystemtechnik, Band 21, Berlin: Deutsches Zentrum für Luft- und Raumfahrt e.V. Institut für Verkehrssystemtechnik, Berlin-Adlershof , 2013, p. 147-164Conference paper (Refereed)
    Abstract [en]

    Variable Speed Limit Systems (VSLS) where gantries are showing speed limits based on, for example, traffic volume or other road or traffic conditions exists on motorways in many countries. The aim of the VSLS is usually to improve traffic efficiency. Lately, cooperative intelligent transport systems allowing for communication between vehicles and/or vehicles and the infrastructure has received increasing interest. A cooperative VSLS, utilizing communication between vehicles and the infrastructure, could possibly result in further improved traffic efficiency and decreased exhaust emissions and fuel consumption. In this paper, a cooperative VSLS is evaluated by the use of a microscopic traffic simulator. The cooperative VSLS is described together with a discussion on how the modeling of the cooperative VSLS and the assumptions made regarding vehicles behavior will impact the final results of the evaluation. Results from the simulations are presented with in terms of traffic efficiency and exhaust emissions.

  • 37.
    Grumert, Ellen
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Tapani, Andreas
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Traffic State Estimation Using Connected Vehicles and Stationary Detectors2018In: Journal of Advanced Transportation, ISSN 0197-6729, E-ISSN 2042-3195, article id UNSP 4106086Article in journal (Refereed)
    Abstract [en]

    Real-time traffic state estimation is of importance for efficient traffic management. This is especially the case for traffic management systems that require fast detection of changes in the traffic conditions in order to apply an effective control measure. In this paper, we propose a method for estimating the traffic state and speed and density, by using connected vehicles combined with stationary detectors. The aim is to allow fast and accurate estimation of changes in the traffic conditions. The proposed method does only require information about the speed and the position of connected vehicles and can make use of sparsely located stationary detectors to limit the dependence on the infrastructure equipment. An evaluation of the proposed method is carried out by microscopic traffic simulation. The traffic state estimated using the proposed method is compared to the true simulated traffic state. Further, the density estimates are compared to density estimates from one detector-based method, one combined method, and one connected-vehicle-based method. The results of the study show that the proposed method is a promising alternative for estimating the traffic state in traffic management applications.

  • 38.
    Grumert, Ellen
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Tapani, Andreas
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Using connected vehicles in a variable speed limit system2017In: Transportation Research Procedia, Elsevier B.V. , 2017, p. 85-92Conference paper (Refereed)
    Abstract [en]

    Variable speed limit systems are used to improve the traffic conditions on specific road stretches. This is done by adjusting the speed limits according to current traffic situations. A variable speed limit system usually consist of stationary detectors to estimate the traffic state and variable message signs at predefined locations for the application of new speed limits. Advances in vehicle technology have made it possible to use connected vehicles to improve existing variable speed limit systems. Connected vehicles can continuously transmit information about speed and location. This can be used to get more detailed information about the traffic state. By including information from connected vehicles in a variable speed limit system there is a potential to identify bottlenecks also in between stationary detectors. Further, it is possible to use direct control of the connected vehicles to adjust vehicle speeds towards the new traffic situation. In this study, we propose such a variable speed limit system based on connected vehicles. The aim is to allow for application of variable speed limits in connection with non-recurrent bottlenecks. The proposed system is evaluated with respect to traffic efficiency using microscopic traffic simulation. An incident is simulated as an example of a non-recurrent bottleneck. The traffic performance when the proposed VSL system is applied is compared to the performance without the system. The results indicate that the VSL system manage to improve traffic efficiency in a majority of the simulated cases.

  • 39.
    Grumert, Ellen
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Tapani, Andreas
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Ma, Xiaoliang
    KTH.
    Characteristics of variable speed limit systems2018In: European Transport Research Review, ISSN 1867-0717, E-ISSN 1866-8887, Vol. 10, no 2, article id 21Article in journal (Refereed)
    Abstract [en]

    The control algorithm used for deciding on the speed limit in variable speed limit systems is crucial for the performance of the systems. The algorithm is designed to fulfil the purpose of the variable speed limit system, which can be one or several of the following aspects: increasing safety, increasing efficiency and decreasing environmental impacts. Today, many of the control algorithms used in practice are based on fixed thresholds in speed and/or flow. Therefore, they are not necessarily reflecting the current traffic conditions. Control algorithms with a greater level of complexity can be found in the literature. In this paper, four existing control algorithms are investigated to conclude on important characteristics affecting the performance of the variable speed limit system. The purpose of the variable speed limit system and, consequently, the design of the control algorithm differ. Requirements of the investigated control algorithms are that they should be easy to interpret and the execution time should be short. The algorithms are evaluated through microscopic traffic simulation. Performance indicators related to traffic safety, traffic efficiency and environmental impacts are presented. The results show that the characteristics of the variable speed limit system and the design of the control algorithm will have effect on the resulting traffic performance, given that the drivers comply with the variable speed limits. Moreover, the time needed to trigger the system, the duration and the size of speed limit reductions, and the location of the congestion are factors of importance for the performance of variable speed limit systems.

  • 40.
    Grumert, Ellen
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics. Linköpings universitet, Kommunikations- och transportsystem.
    Tapani, Andreas
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics. Linköpings universitet, Kommunikations- och transportsystem.
    Ma, Xiaoliang
    Kungliga Tekniska Högskolan (KTH), Stockholm.
    Effects of a Cooperative Variable Speed Limit System on Traffic Performance and Exhaust Emissions2013In: TRB 92nd Annual Meeting Compendium of Papers, 2013Conference paper (Refereed)
    Abstract [en]

    Variable Speed Limit Systems (VSLS) where variable message signs show speed limits based on traffic or road conditions exist on motorways in many countries. The purpose of the VSLS is to decrease the number of accidents while increasing efficiency of traffic system. Cooperative systems are a type of intelligent transport system that has received increasing interest lately. The central part of a cooperative system is communication between vehicles and/or vehicles and the infrastructure. In this paper, a cooperative systems extension of a VSLS is proposed and evaluated by means of microscopic traffic simulation. In the proposed cooperative VSLS, communication between the vehicles and the infrastructure is made available via a roadside unit communicating the speed limits to vehicles upstream on the road. Both aggregate and micro-scale emission models are used to estimate emission from vehicle states in traffic flow. The results of the study show that the cooperative VSLS has a potential to contribute to flow harmonization and to reduce environmental impacts. The emission estimates in the study are dependent on the emission models being applied.

  • 41.
    Gustafsson, Susanne
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Traffic safety, society and road-user.
    Jägerbrand, Annika
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Grumert, Ellen
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Hastighetsdämpande åtgärder: en litteraturstudie med fokus på nya trafikmiljöåtgärder och ITS-orienterade lösningar2011Report (Other academic)
    Abstract [en]

    A literature survey has been conducted regarding international traffic calming measures that could have a potential use in Sweden and other Nordic countries. Focus has been on measures in new traffic environments and ITS (Intelligent Transport System) based solutions. Information has been obtained through searches in literature databases and on different homepages, as well as from contacts in networks. Initially, we describe common traffic calming measures used today in Swedish traffic environments. For example, different forms of vertical and horizontal measures, and different types of surfaces, road markings and paintings. In the case of existing ITS solutions, we mention speed reminder signs, variable message signs and Motorway Control System (MCS).

    New kinds of physical measures that have most potential for use are e.g. modifications of speed bumps and the construction of small curves that enforce lower speed. Such curvatures can be used at entrances to communities or before roundabouts.

    Different concepts of "shared space" (e.g. walking speed zones) are something that could be used more extensively, even at intersections and other locations in urban areas. In such cases, all traditional road equipment is removed and a synergy between different user groups is created, leading to lower speeds.

    Different types of road markings and paintings can be used to visually narrow the road, but also in order to create an optical illusion that makes one feel as if the speed is high. However, such measures are not fully effective during winter conditions. Applications in 3D can also be used to create the illusion of obstacles in the roadway and result in reduced speeds. It is important to consider the overall picture and to combine various measures in a correct way. This report gives some examples on how to implement speed reduction measures in communities with thoroughfares. Furthermore, we give example on how strategic approaches and policy design may help to efficiently implement different kinds of traffic calming measures.

    ITS-solutions, where a two-way communication between vehicles and between vehicles and the infrastructure is used, have gained momentum in Europe and internationally. Three possible systems that have not yet been introduced on the market are described. Most of the cooperative systems are still in a research and development phase. The potential of the systems is considered to be large, and this is also reflected in the extensive research and development investments in the area. Furthermore, ITS as a whole, i.e. cooperative systems as well as other ITS solutions is believed to have a great potential.

  • 42.
    Gyergyay, Bernard
    et al.
    Rupprecht Consult Forschung & Beratung GmbH.
    Gomari, Syrus
    Rupprecht Consult Forschung & Beratung GmbH.
    Olstam, Johan
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Johansson, Fredrik
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Friedrich, Markus
    University of Stuttgart.
    Sonnleitner, Jörg
    University of Stuttgart.
    Rupprecht, Siegfried
    Rupprecht Consult Forschung & Beratung GmbH.
    Backhaus, Wolfgang
    Rupprecht Consult Forschung & Beratung GmbH.
    Automation-ready framework for urban transport planning2018In: Proceedings of 7th Transport Research Arena TRA 2018, April 16-19, 2018, Vienna, Austria, 2018Conference paper (Refereed)
    Abstract [en]

    The mission of the H2020 CoEXist project is to enable mobility stakeholders to get “Automation-ready” – which CoEXist currently defines as conducting transport and infrastructure planning for connected and automated vehicles (CAVs) in the same comprehensive manner as for existing modes such as conventional vehicles, public transport, pedestrians, and cyclists, while ensuring continued support for existing modes on the same network. This definition will be fine-tuned through stakeholder engagement processes. The H2020 CoEXist project started in May 2017 and will run until April 2020. This paper introduces this project and covers its progress until January 2018, with a focus on the methodology of the “Automation-ready framework” that provides a planning framework for urban road authorities to prepare for the introduction of CAVs on the road network. The framework includes elements about strategic urban mobility planning for CAVs and a clear guide for urban transport planners with a list of concrete actions that cities can do now to plan for CAVs on their road network

  • 43.
    Hainz, Svenja
    et al.
    Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR).
    Vannier, Elodie
    SNCF .
    Meyer zu Hoerste, Michael
    Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR).
    Kristoffersson, Ida
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Passenger Demand in a Technical World2018Conference paper (Refereed)
  • 44.
    Hammarström, Ulf
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Enviroment and traffic analysis.
    Eriksson, Jenny
    Swedish National Road and Transport Research Institute, Traffic and road users, Traffic safety, society and road-user.
    Karlsson, Rune
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Yahya, Mohammad Reza
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Rolling resistance model, fuel consumption model and the traffic energy saving potential from changed road surface conditions2012Report (Other academic)
    Abstract [en]

    In order to evaluate traffic energy changes due to the improvement of road surface standard one need to describe:

    • • rolling resistance at different road surface conditions
    • • all other driving resistance
    • • fuel consumption (Fc) as a function of driving resistance.

    Based mainly on empirical data from coastdown measurements in Sweden a general rolling resistance model – with roughness (iri), macrotexture (mpd), temperature and speed as explanatory variables – was developed and calibrated for a car; a heavy truck and a heavy truck with trailer.

    This rolling resistance model has been incorporated into a driving resistance based Fc model with a high degree of explanation. The Fc function also includes variables for horizontal curvature (ADC) and the road gradient (RF). If mpd per road link is reduced by up to 0.5 mm, the total Fc in the road network will be reduced by 1.1%. By reducing iri per link by 0.5 m/km, speed will increase in parallel to reduced rolling resistance and there will be approximately no resulting effect on Fc. If rut depth is decreased in parallel to iri there will be a further increase in speed. For individual road links there might be an energy saving potential if the proportion of heavy vehicles is big enough.

  • 45.
    Hammarström, Ulf
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Enviroment and traffic analysis.
    Haider, Manfred
    Austrian Institute of Technology (AIT).
    Conter, Marco
    Austrian Institute of Technology (AIT).
    Goubert, Luc
    Belgian Road Research Centre (BRRC).
    Bergiers, Anneleen
    Belgian Road Research Centre (BRRC).
    Glaeser, Klaus-Peter
    Federal Highway Research Institute (BASt).
    Schwalbe, Gernot
    Federal Highway Research Institute (BASt).
    Zöller, Marek
    Federal Highway Research Institute (BASt).
    Boujard, Olivier
    IFSTTAR.
    Karlsson, Rune
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Ejsmont, Jerzy A.
    Technical University of Gdansk (TUG).
    Wang, T
    University of California, Pavement Research Center, UC Davis and Berkeley, Davis, California.
    Harvey, J.T.
    University of California, Pavement Research Center, UC Davis and Berkeley, Davis, California.
    Rolling resistance: basic information and state-of-the-art on measurement methods. Final version2011Report (Other academic)
    Abstract [en]

    MIRIAM has established a sub-project (SP), designated SP 1, to deal with measurement methods for rolling resistance and related issues. This subject forms the most fundamental basis for the MIRIAM ambition to consider rolling resistance in pavement management or other types of infrastructure systems. Without robust measurement methods and equipment that can use them there will be no reliable data as input to such systems and the end result will be most uncertain, if useful at all.

    In order to develop and study measurement methods, there must be a basic understanding of the influencing parameters as well as what energy losses that should be included in the concept of rolling resistance. These issues are, therefore, important parts of the work in SP 1.

    This report is intended to provide basic knowledge about the part of the tyre and road interaction which relates to rolling resistance; for example, the mechanisms that create rolling resistance, and the influence on rolling resistance of various tyre and road parameters. The intention is also to suggest a definition of rolling resistance for the purposes of this project, as well as to provide some detailed state-of-the-art knowledge about the measurement methods and equipment that are useful for collecting rolling resistance data.

  • 46.
    Hammarström, Ulf
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Enviroment and traffic analysis.
    Karlsson, Rune
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Sörensen, Harry
    Swedish National Road and Transport Research Institute, Infrastructure, Measurement technology and engineering workshop.
    Yahya, Mohammad Reza
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Coastdown measurement with 60-tonne truck and trailer: estimation of transmission, rolling and air resistance2012Report (Other academic)
    Abstract [en]

    By use of coastdown measurements, driving resistance parameters have been estimated for a truck with trailer (60t) and a box vehicle body. At a vehicle speed of 20 m/s, average meteorological wind conditions and a load factor of 50% the following distribution of the driving resistance components has been obtained:

    • transmission resistance (churning losses), 5%
    • rolling resistance (test route surface conditions), 41%
    • air resistance, 54%.

    There are also measurements for the truck without a trailer. Rolling resistance is dependent on road surface conditions, in particular roughness (iri) and macro texture (mpd). The total rolling resistance consists of three parts: a basic, an iri and a mpd part. The road surface effect amounts to approximately 40% of the total rolling resistance. The iri effect seems to be the dominating part of the surface effects on the contrary to light vehicles.

    Driving resistance parameters have been estimated by means of regression analysis. A major problem is how to avoid high correlations between explanatory variables. One objective of the experiment design has been to minimize such dependencies. This study might also be of interest for methodological reasons and in particular for including:

    • the introduction of high accuracy road gradients as well as other road surface properties
    • the estimation of vehicle mass from coastdown to coastdown
    • the equipment (based on Doppler technique) used in order to measure the coastdown driving pattern
    • the method used in order to separate parts of the driving resistance
  • 47.
    Hammarström, Ulf
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Enviroment and traffic analysis.
    Yahya, Mohammad Reza
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    An analysis of the Swedish HGV fleet with driving resistance in focus: vehicle parameters as a basis for HBEFA emission factor estimation2013Report (Other academic)
    Abstract [en]

    In order to estimate energy use and exhaust emissions from road traffic, on a regional or a national level, one needs representative emission factors. Emission factors are estimated based on vehicle driving resistance. Driving resistance is estimated based on representative driving patterns and vehicle parameters. In the HBEFA program, used for estimation of road traffic exhaust emissions, the vehicle fleet is divided into vehicle categories. One such category is Heavy Goods Vehicles (HGV). The HGV category is divided into vehicle segments after maximum vehicle weight (GVW). One further division is into vehicle combinations, a rigid truck (RT) or a truck with trailer (TT). Vehicle segments are divided into Euro classes approximately corresponding to year model intervals. For each segment and Euro class there is a set of emission factors. Then there is need for vehicle parameters per vehicle segment and Euro class. HGV emission factors on the Euro class level are treated as independent of calculation year. Emission factors for HGV vehicles in HBEFA are calculated by means of the PHEM computer program. The PHEM simulations are based on driving resistance estimation. In order to estimate vehicle parameters, data available in the Swedish national vehicle register (1997, 2004 and 2009) and in transport surveys (1997 and 2003) has been compiled. Survey data including mileage is necessary in order to estimate vehicle parameters for average road conditions. The split into RT and TT segments demands access to mileage data describing the use of trailer. The total number of HGV in the Swedish vehicle fleet is approximately the same 2010 as 1990. Despite this there are most important changes within the HGV fleet in this time period, such as the proportion of trucks with GVW>26t has increased from 6 to 36 per cent. In this group there are some segments with very large changes of proportion. In parallel to an important change in the segment distribution one could expect a change in distribution also inside individual segments and Euro classes by time influencing the average vehicle parameters and finally the emission factors.

  • 48.
    Haraldsson, Mattias
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics Stockholm.
    Jonsson, Lina
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics Stockholm.
    Karlsson, Robert
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Vierth, Inge
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics Stockholm.
    Yahya, Mohammad Reza
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Ögren, Mikael
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Samhällsekonomisk analys av rundvirkestransporter med 90-tonslastbilar: delprojekt inom Sammodalitetsprojektet2012Report (Other academic)
    Abstract [en]

    The purpose of this report is to make a cost benefit analysis, showing how costs for truck transports of round wood would change if vehicles with a total weight of 90 tonnes were used instead of the 60-tonne vehicles that are currently in use. The analysis has two parts. First, costs per vehicle kilometre are presented for both vehicle sizes. This gives a good general view but does not take into account the various conditions with regard to road type, etcetera, that affect costs. Neither does it take into account that the amount of vehicle kilometres associated with round wood transports changes if larger vehicles are allowed. Therefore a scenario analysis is also performed. The basis for this analysis is simulations using the Swedish transport and logistics system Samgods. Flow estimates from Samgods are combined with road attribute data from the national road database (NVDB) to compute the total transport cost, including externalities. In these computations road type and other situation specific factors are taken into account. The scenario analysis is summarized by the total annual cost for road transports of round wood in Sweden. Due to the simulations the amount of vehicle kilometres are reduced by 21 percent if 60-tonne vehicles are replace by 90-tonne vehicles, given that the capacity of bridges is left without regard. In socioeconomic terms this equals cost reduction of 4 per cent of 163 million Swedish crowns annually. It should be kept in mind, though, that costs for improving bridge capacity, which is required for this scenario to be realized, are not included in the analysis. When 90-tonne vehicles are not allowed to pass bridges with limited bearing capacity, larger vehicles do not generally improve efficiency. There are however some important round wood transport routes where larger vehicles are possible to use without any measures to improve bridges.

  • 49.
    Hegeman, Geertje
    et al.
    DHV BV Mobility Department.
    Tapani, Andreas
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics. Linköpings universitet, Kommunikations- och transportsystem.
    Hoogendoorn, Serge
    Delft University of Technology.
    Overtaking assistant assessment using traffic simulation2009In: Transportation Research Part C: Emerging Technologies, ISSN 0968-090X, E-ISSN 1879-2359, Vol. 17, no 6, p. 617-630Article in journal (Refereed)
    Abstract [en]

    This contribution presents the results of a microscopic traffic simulation study of the potential effects of an overtaking assistant for two-lane rural roads. The overtaking assistant is developed to support drivers in judging whether or not an overtaking opportunity can be accepted based on the distance to the next oncoming vehicle. Drivers have been found to consider this to be a difficult part of an overtaking manoeuvre. The assistants effects on traffic efficiency, driver comfort and road safety have been investigated using traffic simulation. The results indicate that this type of overtaking assistant can provide safety benefits in terms of increased average time-to-collision to the next oncoming vehicle during overtaking manoeuvres. This safety benefit can be achieved without negative consequences for traffic efficiency and driver comfort. A driver assistance system that supports the distance judging part of overtaking manoeuvres can therefore contribute to improved traffic conditions on the two-lane rural roads of the future.

  • 50.
    Henriksson, Malin
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Mobility, actors and planning processes.
    Berg, Jessica
    Swedish National Road and Transport Research Institute, Society, environment and transport, Mobility, actors and planning processes.
    Karlsson, Jenny
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Rogerson, Sara
    SSPA.
    Winslott Hiselius, Lena
    LTH.
    Köpa mat online?: effekter av ökad e-handel för person- och godstransporter i ett växande e-handelssamhälle2018Report (Other academic)
    Abstract [en]

    In recent years, e-commerce of food has increased substantially. Today, calculations of e-commerce’s energy efficiency potential build on estimates and assumptions rather than knowledge of the industry and its customers. This study generates in-depth knowledge of what it means from a transport perspective that companies instead of individuals are responsible for transporting food to the home. The main purpose of this project is to analyze effects as a result of increased online food shopping and to identify factors that enable realization of potential energy savings potential. This is done from a regional perspective and in a Swedish context. The purpose has been achieved through a review of the prerequisites for energy-efficient distribution solutions for e-commerce offers, and through interviews with existing and potential e-commerce customers’ preferences, experiences and behaviors.

    The results indicate that e-commerce has a significant theoretical potential. However, this require that effective routes replace purchase trips with private cars. Today, due to continued frequent car trips to food stores, e-commerce does not replace purchase trips sufficiently enough. In order for the potential to be achieved, there is a need for an expanded customer base and urban planning that prioritizes walking, biking and public transport, and that raises city logistics as a strategic issue and finally that locates food stores close to people’s homes.

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