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  • Eriksson, Olle
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Sörensen, Gunilla
    Swedish National Road and Transport Research Institute, Traffic and road users, Traffic Safety and Traffic System.
    Motorcykelflöden sommarhalvåren 2006 – 2017: teknisk rapport, version 1.02018Report (Other academic)
    Abstract [sv]

    Trafikverket ser ett ökat behov av uppgifter om trafikflöden och fordonshastigheter för motorcyklar, speciellt med avseende på tillförlitliga data inom trafiksäkerhetsområdet. Vid olycksanalys är det till exempel svårt att finna exponeringsdata för motorcykliste. För mc-flöden finns en särskild metod framtagen, se PM ”Beräkningar av mc-flöden på Trafikverkets ÅDT-avsnitt” (Eriksson, 2013).

    Skattningar av trafikflöden tas fram på basis av ett 12-årigt mätprogram för årsmedel-dygnstrafik (ÅDT). Sedan år 2006 skattas även mc-flöde under sommarhalvåret med hjälp av data från mätprogrammet. Skattningar av mc-flöden på de statliga vägarna år 2006–2012 utfördes enligt metoden beskriven i Eriksson (2013). Motsvarande skattningar gjordes även för år 2013–2014 med denna metod, enligt uppgift från Trafikverket. Metoden användes också för skattningar år 2015, men då genomfördes dessutom ytterligare rimlighetskontroller och korrigeringar av data, vilket är beskrivet i teknisk rapport ”Trafikflöden för motorcyklar 2015” (Sörensen och Eriksson, 2016). Metoden vidareutvecklades för skattningarna år 2016, se Sörensen, Henriksson och Yahya (2017).

    Resultaten av mc-flödesskattningarna har rapporterats till Trafikverket i tabellform uppdelade per mätår och vägkategori. Trafikverket har publicerat resultaten i kartor på sin websida.

  • Jacobson, Bengt J H
    et al.
    Chalmers.
    Sundström, Peter
    Kharrazi, Sogol
    Swedish National Road and Transport Research Institute, Traffic and road users, Driver and vehicle.
    Fröjd, Niklas
    Islam, Manjurul
    Chalmers.
    An Open Assessment Tool for Performance Based Standards of Long Combination Vehicles2017Report (Other academic)
    Abstract [en]

    The project “Performance Based Standards for High Capacity Transports in Sweden” (Performance Based Standards for High Capacity Transports in Sweden, 2013-2017) have generated a first version of an open PBS assessment tool, OpenPBS. The tool uses models and computations to calculate Performance Based Standards (PBS) measures for combination vehicles. The tool targets Long Combination Vehicles (LCVs, typically 25-35 m) but it can also calculate PBSes for shorter combinations and solo units. This report describes the tool. The report explains the concepts selected for the tool. Future developments are proposed.

  • 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.
    Bottleneck mitigation through a variable speed limit system using connected vehicles2018In: Transportmetrica A: Transport Science, ISSN 2324-9935Article in journal (Refereed)
    Abstract [en]

    Variable speed limit (VSL) systems are used to improve the traffic conditions by adjusting the speed limits based on the current traffic situation. Advances in vehicle technology have made it possible to use connected vehicles in VSL systems. Connected vehicles can continuously transmit information about their speed and location, which can be used to estimate the current traffic conditions at arbitrary locations. In this study, we propose a VSL system based on connected vehicles. The aim is to also allow application of VSLs for non-recurrent bottleneck mitigation at arbitrary locations, unlike today's systems which require densely placed detectors or are limited to beforehand known bottleneck locations. The proposed system is evaluated by microscopic traffic simulation. The results indicate that the VSL system manage to improve traffic efficiency in a simulated incident scenario.

  • Niska, Anna
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Blomqvist, Göran
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Hjort, Mattias
    Swedish National Road and Transport Research Institute, Traffic and road users, Driver and vehicle.
    Cykelvägars friktion: mätningar i fält i jämförelse med cykeldäcks friktion på olika underlag i VTI:s däckprovningsanläggning2018Report (Other academic)
    Abstract [en]

    Skidding is a common cause for cyclists getting seriously injured in traffic. Neither requirements nor prescribed friction measurement methods for cycleways have been based on the performance of bicycles. There is therefore a need for increased knowledge regarding the friction characteristics of bicycle tyres and the traction between a bicycle tyre and the road surface under different conditions. In this project we have compiled measurements with VTI's portable friction tester, PFT, on cycleways with a variety of road conditions. To relate the PFT friction values to the friction of bicycle tyres, we have also made comparative measurements with bicycle tyres in VTI's stationary tyre testing facility. These show a very good match between the PFT friction values and the maximum lateral friction available for a bicycle tyre. This means that the PFT friction values recorded on cycleways can also be said to represent the friction that a bicycle tyre would perform on the same surface. Our friction measurements on cycleways show that the skid resistance is affected by the road condition, the road surface material, as well as road markings and manhole-covers. Ice and snow cause a significantly lower friction level than at bare conditions. Differences in road conditions mean that different types of cycling infrastructure and different winter maintenance methods result in different friction levels. This means that there may be large variations in friction along one and the same cycle route. The surprise effect and thus the accident risk can then be great. Not only snow, ice and grit, but also leaves, clay and other dirt on the surface might lead to a reduced skid resistance. For the safety of cyclists, it is important to inform about where a slippery condition can occur and to adjust anti-icing actions, road design and construction according to that knowledge.