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  • 1.
    Andersson, Håkan
    Swedish National Road and Transport Research Institute.
    Vägräcken och risker för mc-förare vid påkörning i liten vinkel2005Report (Other academic)
    Abstract [sv]

    Vägräcken är inte anpassade till motorcyklars specifika problem. Trots en omfattande mytbildning finns det dock inte något stort material som styrker farhågorna om att räcket är speciellt farligt för motorcyklisten. Det konstateras (trots allt) att det saknas kunskap, att de prov som gjorts inte tar sikte på motorcyklars specifika problem samt att det synes lämpligt att på något sätt försöka införskaffa denna kunskap. På kort sikt föreslås någon form av bedömning av räckens lämplighet på empirisk grund för att på längre sikt försöka påverka standarden EN1317 så att den tar hänsyn även till motorcyklistens behov.

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  • 2.
    Bruzelius, Fredrik
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Hjort, Mattias
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Andersson, Håkan
    Swedish National Road and Transport Research Institute, Infrastructure, Crash safety.
    Towards an Indoor Winter Tire Classification Test2012In: Proceedings of VSDIA 2012, 2012Conference paper (Refereed)
    Abstract [en]

    From a traffic safety perspective it is highly motivated to define winter tires interms of their performance in icy road conditions. The present definition of winter(snow) tires, introduced in the EU in 2012, is based on packed snow performance.The present paper investigates the feasibility of an indoor winter tire classificationtest on ice. Results presented here indicates that a test procedure in an indoorhockey rink is possible, with relatively high repeatability. However, further fieldtest is required to fully establish feasibility of the procedure.

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  • 3. Camuffo, I
    et al.
    Fürstenberg, K
    Westhoff, D
    Aparicio, A
    Zlocki, A
    Lützow, J
    Benmimoun, M
    Lesemann, M
    Iglesias, I
    Isasi, L
    Murgoitio, J
    Jacobson, J
    Eriksson, H
    Herard, J
    Leanderson, S
    Heinig, K
    Karlsson, A-S
    Jansson, Jonas
    Swedish National Road and Transport Research Institute.
    Andersson, Håkan
    Swedish National Road and Transport Research Institute.
    State of the art and eVALUE scope2008Report (Other academic)
    Abstract [en]

    eVALUE will address the real function of ICT-based safety systems and their capability to perform the function through two courses of action: defining and quantifying the function output to be achieved by the safety system and developing the testing and evaluation methods for the ICT-based safety systems. The safety systems within the eVALUE scope are classified into four clusters: longitudinal, lateral and yaw/stability. The fourth cluster remains open for upcoming systems. Based on market availability and penetration rate, the consortium decided to focus on eight preventive or mitigating safety systems: ACC, FCW and CM by braking, in the longitudinal assistance domain; BSD, LDW and LKA, in the lateral assistance domain; and finally, ABS and ESC, in the yaw/stability assistance domain. Following the description of current test and evaluation methods, sensor technologies, system function output and ECUs globally applicable to ICT based safety systems, the report covers these technologies and components for the eight selected systems in detail. As a next step to this deliverable and according to the work plan, concepts for design reviews, physical vehicle testing as well as laboratory testing will be analysed. The result will be an in-depth understanding of the possibilities to investigate and evaluate the eight active safety systems within the first phase of the project. The different concepts will then support the decision about the development of the testing and evaluation methods that are able to point out the safety benefit of those systems in the most representative way.

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  • 4.
    Hjort, Mattias
    et al.
    Swedish National Road and Transport Research Institute.
    Andersson, Håkan
    Swedish National Road and Transport Research Institute.
    Däckens betydelse för antisladdsystems funktion på isigt underlag2009Report (Other academic)
    Abstract [sv]

    In this study we have investigated how tyres with different road grip affect the stability of passenger cars equipped with Electronic Stability Control (ESC) systems during winter road conditions. The introduction of ESC in passenger cars has been very positive for traffic safety. An ESC system's function is however dependent on forces between road and tyres. Thus, it is not clear how important the tyre road grip performance is for the ESC system to function properly. Field tests on ice with six different drivers were used for assessing how well an ESC system can help the driver in a specific critical situation during slippery road conditions, namely a sudden double lane change. Four different studless winter tyres were used in the study: one studless winter tyre for Nordic conditions, and three studless winter tyres for central European conditions. The specific tyres were chosen to represent a large difference of road grip on ice and snow, and winter tyre tests in the media served as a guide for picking out the tyres.

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  • 5.
    Hjort, Mattias
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Andersson, Håkan
    Swedish National Road and Transport Research Institute, Infrastructure, Crash safety.
    Säkerhetsrisker kopplat till däck, fälg och hjul: en litteraturstudie2012Report (Other academic)
    Abstract [en]

    A literature review about the road safety effects associated with tires, rims and wheels was carried out, where the literature search was done in consultation with the VTI Library and information centre. The outcome resulted in approximately 90 different references, most of which refer to research articles in peer reviewed journals, but also some independent reports and books. A clear distinction was made with slip-related accidents related to winter conditions and different types of snow tires/tire characteristics not included in the study. Furthermore, only the type of accidents that occurs during vehicle operation was treated, which means that work accidents occurring during a service are not included in the study.

    There is not much research published on the rim effect on road safety, and a U.S. accident investigator believes that the wheels generally are extremely reliable. Of the anomalies that can occur for the wheel as a whole, loosening of the wheel is the most serious. The studies that we found dealing with wheel imbalance only apply to comfort problems and increased road wear. Different wheel alignment will affect a vehicle's handling, but we have not found any study that has related this to road safety. For tires, we found no research on how different tire sizes and brands mounted on a vehicle affect its safety. Several studies show that there is a risk involved with mounting new tires on the front axle and worn tires on the rear axle. There is a consensus that during the replacement of two tires, the new tires should always be positioned on the rear axle, regardless if the vehicle is front or rear wheel driven. A number of studies show how the tread depth affects the wet grip during braking, and how the tires with less than 3 mm tread depth lose about half of the available friction compared to new tires.

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  • 6.
    Hjort, Mattias
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Andersson, Håkan
    Swedish National Road and Transport Research Institute.
    Jansson, Jonas
    Swedish National Road and Transport Research Institute, Traffic and road users.
    Mårdh, Selina
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Sundström, Jerker
    Swedish National Road and Transport Research Institute.
    A test method for evaluating safety aspects of ESC equipped passenger cars: a prototype proposal2009Report (Other academic)
    Abstract [en]

    Active safety systems are becoming increasingly common in today's vehicles. Electronic Stability Control (ESC) systems were introduced during the end of the 1990s, and accident statistics show that they have had a huge impact on traffic safety. In the USA, a new legislation has recently been adopted which demands on every new light vehicle that is sold to be equipped with ESC, beginning 2011. New systems require new testing methods, and there is a need expressed by the New Car Assessment Program (NCAP), which at present time only evaluates the passive safety of cars, also to include tests for active safety systems. In a previous VTI work, a literature review regarding methods for the evaluation of traffic safety effects of Antilock Braking Systems (ABS) and ESC was performed. Based on the findings of that review, we have proceeded with defining a test method for evaluating safety aspects of ESC equipped passenger cars. The objective has been to suggest a (prototype) test method that can be used for a more holistic evaluation of the safety effect of ESC in cars, including the driver behaviour perspective. From discussions with leading experts on traffic safety and ESC, possible benefits of ESC systems on traffic safety were identified. In addition to increasing the yaw stability of the vehicle, the following ESC benefit effects were identified: - A warning system for slippery roads. ESC activation indication may act as a warning system to the driver about slippery road conditions. - Reduced collision speed. In a critical situation, ESC activation may reduce the collision speed, which will mitigate the outcome of the collision. - Improved vehicle roll stability. The ESC system may also stabilise the vehicle with respect to untripped rollovers. Most rollovers are however tripped rollovers, which can occur when a vehicle, with some lateral slip, strikes an object or slides off the road. These rollovers also benefit from the ESC system as it aids in keeping the vehicle on the road.

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  • 7.
    Hjort, Mattias
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Bruzelius, Fredrik
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Andersson, Håkan
    Swedish National Road and Transport Research Institute, Infrastructure, Crash safety.
    The importance of tyre grip for the ESC function on icy roads2011Conference paper (Refereed)
    Abstract [en]

    In this study we have investigated how tyres with different road grip affect the stability of passenger cars equipped with Electronic Stability Control (ESC) systems during winter road conditions. A field test with a double lane change manoeuvre on ice was performed using 6 test drivers, 4 different passenger cars and 4 different studless winter tyres. The specific tyres were chosen to represent a large difference of road grip on ice and snow. The results show that there was a large performance difference between the best and worst tyres with ESC off, and that activating ESC only resulted in a minor increase of performance.

  • 8.
    Hjort, Mattias
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Bruzelius, Fredrik
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Andersson, Håkan
    Swedish National Road and Transport Research Institute, Infrastructure, Crash safety.
    Överstyrning på is och snö med olika vinterdäck: metodutveckling och fältstudie2011Report (Other academic)
    Abstract [en]

    Traffic accidents during winter time are to a larger extent categorized by loss of vehicle control resulting in a skidding accident, compared to accidents occurring summer time. In a study by the Swedish Transport Administration, it was shown that for fatal accidents happening winter time, skidding had occurred in 64 per cent of the accidents on winter road conditions. Out of these, 82 per cent were so called over steering accidents, i.e. events where the vehicle starts to spin.

    The purpose of this study was to develop av method for testing a vehicle's stability during oversteering on slippery roadways, and to use this method to test how large the difference is between different kinds of winter tyres on ice and snow.

    A test method based on NTHSA's sine-with-dwell manoueuvre was developed. The manouevre uses a steering robot and induces heavy oversteering on slippery surfaces, such as ice and snow.

    The manouevre was then used with an ESC equipped rear-wheel driven passenger car, fitted with both new and worn winter tyres of the three different kinds that are available in Sweden, to compare the level of oversteering that is possible to obtain with a steering manouevre on different ice and snow surfaces. The results show that studded tyres are more stable than unstudded on smooth ice. Even the worn studded tyre, with only a fraction of the studs remaining, is performing well compared to the unstudded tyres, and is comparable to a new unstudded winter tyre of Nordic type and much better than the tyres of Central European type. The winter tyres of Central European type stand out as those generating most oversteering on this surface. On surfaces with higher friction level, the tyres with least grip are also those that generate least oversteering, which makes it difficult to discuss these results in terms of traffic safety.

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  • 9.
    Hjort, Mattias
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Bruzelius, Fredrik
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Andersson, Håkan
    Swedish National Road and Transport Research Institute, Infrastructure, Crash safety.
    Kharrazi, Sogol
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Towards a method for determining maximum oversteer in slippery conditions2013In: Proceedings of 23rd International Symposium on Dynamics of Vehicles on Roads and Tracks (IAVSD'13). Qingdao, China, 19-23 August, 2013., 2013Conference paper (Refereed)
    Abstract [en]

    Fatal accidents during winter time in Sweden are to a large extent due to vehicle spinning. Therefore, it is crucial to analyse and compare vehicle/tyre performance on slippery roads with respect to oversteering. In this study, a new test method for evaluation of vehicle's stability during oversteering on icy roadways is developed and evaluated using a series of tests with a rear wheel driven car, equipped with ESC, and six different tyres on ice test tracks in northern Sweden. The test method consists of an asymmetric sine-with-dwell manoeuvre and a measure forquantifying the level of oversteering based on the relation between yaw rate and lateral acceleration. The test results show good robustness of the method, and that it can successfully rate the various tyres performance on polished ice. However, to have a fair comparison, the proposed method should be modified to take into account the steering ability of the tyres and the consequent difference in the manoeuvre severity when tested with tyres with different side grip.

  • 10.
    Hjort, Mattias
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Bruzelius, Fredrik
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Andersson, Håkan
    Swedish National Road and Transport Research Institute, Infrastructure, Crash safety.
    Krafft, Maria
    Folksam.
    Ydenius, Anders
    Folksam.
    Rizzi, Matteo
    Vectura.
    Jämförelse av vinter och sommardäck på barmark sommartid: tester, riskanalys och djupstudier2015Report (Other academic)
    Abstract [en]

    In Sweden non-studded winter tyres has become increasingly popular during the winter season. Since it is allowed to use non-studded winter tyres also during summer time, a large number of drivers choose to do that. The purpose of this study has been to investigate the difference in road grip between winter- and summer tyres summer time, and to assess possible effects on traffic safety. A field test was carried out where road grip was measured on dry and wet asphalt pavement with different types of tyres. The results showed that the winter tyres (non-studded of Nordic type) led to 15–20 per cent longer braking distances compared to summer tyres. Accident risk analyses were performed for three types of accidents: rear end collision, frontal collision and collision with pedestrian. The study indicated that using winter tyres leads to an increase in accident risk for all three accident types. At low collision speeds the absolute increase in risk is small, maybe just a few percent, but the relative increase may be large, sometimes up to 100 per cent. In-depth studies of fatal accidents indicated a 3 per cent increase of risk from using winter tyres summertime, compared to summer tyres. However, this result was not statistically significant.

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  • 11.
    Thomson, Robert William
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Traffic safety, society and road-user.
    Sandin, Jesper
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Bagdadi, Omar
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Hjort, Mattias
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Augusto, Bruno
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Andersson, Håkan
    Swedish National Road and Transport Research Institute, Infrastructure, Crash safety.
    EDR Pre-Crash Data: Potential For Applications In Active Safety Testing2013In: Proceedings of the 23rd International Technical Conference on the Enhanced Safety of Vehicles, May 2013, Seoul, 2013, article id 13-0414Conference paper (Refereed)
    Abstract [en]

    Passive safety testing has been based on accident research where objective physical evidence can be compiled and analysed when establishing technical test requirements. Active safety tests pose new challenges because objective data is more difficult to obtain. Until pre-crash variables became available in Event Data Recorders (EDR), the only sources of pre-crash vehicle motions were tire marks or witness statements. Both data sources have limitations since they may not always be available and require interpretation by the analyst. The pre-crash EDR data variables provide an objective source of data to active safety test development. However, the suitability of the data has not been thoroughly investigated in the published literature.

    The review of existing data shows that the variables identified in the new EDR requirement in FMVSS 563 are useful but incomplete for a comprehensive analysis of vehicle dynamics manoeuvres prior to a crash. In particular, the absence of vehicle yaw rate reduces the positioning accuracy of the vehicle in reconstructions. The objective data in the limited cases were used to compile the frequency of pre-crash braking and steering, and when possible, the magnitude of these driver inputs. Active Safety test development will benefit with more EDR analysis but the older data that does not conform to Part 563 has limited application.

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  • 12.
    Wenäll, Jan
    et al.
    Swedish National Road and Transport Research Institute.
    Andersson, Håkan
    Swedish National Road and Transport Research Institute.
    Polisens personliga utrustning i olycka2005Report (Other academic)
    Abstract [sv]

    VTI blev kontaktade av Rikspolisstyrelsen med anledning av interna

    funderingar specifikt efter en trafikolycka där en kvinnlig polis

    förolyckats. Även om inget vid denna olycka specifikt pekat på att den

    utrustning som polisen bar på sin uniform direkt förorsakat olyckans tragiska

    utgång, väcktes tankar om att undersöka om det fanns risker med någon av all

    den utrustning som bärs på

    uniformen och om det därmed också gick att identifiera några lämpliga

    åtgärder för att förändra eller reducera riskerna. Därmed bestämdes att,

    genom att utföra två kollisionsprov, arbetsmiljön för polisen i polisbil av

    personbilstyp skulle studeras. I två stycken krockprov testades hypotesen att

    polisens personliga utrustning på uniformen kunde påverka bilbältes funktion

    vid kollision. Sammanfattningsvis kan konstateras att inget därvid framkom

    som tyder på att skyddsvästen har någon signifikant negativ inverkan på

    bilbältets funktion. Vidare konstateras att de utrustningsdetaljer som var

    för sig monteras på utrustningsbältet runt midjan inte i sig innebär

    signifikanta riskökningar, även om det givetvis inte kan uteslutas att även

    små men vassa föremål i olyckliga fall kan ge lokala men svåra skador, men

    att mera generellt kan konstateras att bältets omfång rent fysiskt driver

    bort höftdelen av bilbältet från korrekt anliggning mot den bältade personens

    höft, varvid uppenbar risk för s.k. underglidning uppstår. En normal s.k.

    bältesförsträckare förmår inte i nuläget hämta hem allt det slack som

    utrustningen inducerar

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1 - 12 of 12
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