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  • 1.
    Abadir Guirgis, Georg
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Lärarperspektiv på riskutbildningen för motorcyklister2011Report (Other academic)
    Abstract [en]

    Over the last decade it has become increasingly popular to ride a motorcycle in Sweden. A mandatory risk education for competence A and A1 was introduced from the 1st of November 2009. Since the education is new, few evaluations have been conducted so far.

    This study evaluates the risk education for motorcyclists based on the perspective of driving instructors. The goal was to compile the instructors' comments and experiences with respect to the new risk training. An additional objective was to examine the driving instructors' perceived effects of the education on their students' driving behavior. Six semi-structured interviews with driving instructors and an observational study of the education at various driving schools were conducted. In addition, a participant observation study was performed during a further education of 15 driving instructors. The results show that the instructors experience a great need for the new risk training and that the implementation of the training itself has been good. Students have been referring to the risk training, which according to the instructors indicate that the students have embraced the essence of the training. As a result, the students drive more carefully now and think twice in certain situations according to the instructors. This was considered a desirable result.

  • 2.
    Abadir Guirgis, Georg
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Peters, Björn
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Simulatorbaserad utbildning i ERTMS: utvärdering av utbildning och träning för lokförare i VTI:s tågsimulator2015Report (Other academic)
    Abstract [en]

    The purpose of this study was to evaluate the VTI train simulator with regard to simulator-based training and education in the ERTMS (European Rail Traffic Management System) system for train drivers, compared to the ERSA simulator. The purpose was also to study two different ways of combining theoretical education with practical training in a simulator. In the future, the major railway routes in Sweden will be equipped with ERTMS. This will require considerable training for Sweden’s approximately 3,500 train drivers in future need of ERTMS education. It is unrealistic to think that these should be trained on real tracks. Therefore, there is a need for a more realistic ERTMS simulator compared to the European Rail Software Applications (ERSA) simulator that Trafikverket provides. The study was conducted as a between group design with two measurements. Three different groups were compared under different conditions. Theoretical education in ERTMS combined with training in the ERSA simulator (group 0), theoretical education in ERTMS ending with training in the VTI-simulator (group 1) and theoretical education in ERTMS partly alternated with training in the VTI-simulator (group 2).

  • 3.
    Abadir Guirgis, Georg
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Peters, Björn
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Lidström, Mats
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Lokförarutbildning i Sverige: simulatoranvändning och ERTMS2014Report (Other academic)
    Abstract [en]

    This report, which provides an overview of the compulsory basic training for train drivers in Sweden, highlights the occurrence of simulator-based training in education, along with the training efforts being made with regards to the future introduction of ERTMS/ETCS. The report also shows the possibilities and limitations of increased use of simulators in driver training and describes the most important governing documents for train drivers and train driver training. Furthermore, the Swedish Transport Agency curriculum for train driver licenses is presented along with the institutions engaged in basic education, training and examination of train driver’s. Also, the Swedish Transport Administration’s E-learning tool for ERTMS, the ERSA-simulator and company specific ERTMS education at SJ and Green Cargo are described. Moreover, Swedish train companies’ and educators’ current use and future needs of simulators for train driver training were examined. Examples from other domains where simulators are used in a training context are also presented.

  • 4.
    Abtahi, Farhad
    et al.
    Kungliga Tekniska Högskolan.
    Anund, Anna
    Swedish National Road and Transport Research Institute, Traffic and road users, Human Factors in the Transport System.
    Fors, Carina
    Swedish National Road and Transport Research Institute, Traffic and road users, Human Factors in the Transport System.
    Seoane, Fernando
    Kungliga Tekniska Högskolan.
    Lindecrantz, Kaj
    Kungliga Tekniska Högskolan.
    Association of drivers’ sleepiness with heart rate variability: A pilot study with drivers on real roads2018In: IFMBE Proceedings, Springer Verlag , 2018, Vol. 65, p. 149-152Conference paper (Refereed)
    Abstract [en]

    Vehicle crashes lead to huge economic and social consequences, and one non-negligible cause of accident is driver sleepiness. Driver sleepiness analysis based on the monitoring of vehicle acceleration, steering and deviation from the road or physiological and behavioral monitoring of the driver, e.g., monitoring of yawning, head pose, eye blinks and eye closures, electroencephalogram, electrooculogram, electromyogram and electrocardiogram (ECG), have been used as a part of sleepiness alert systems.

    Heart rate variability (HRV) is a potential method for monitoring of driver sleepiness. Despite previous positive reports from the use of HRV for sleepiness detection, results are often inconsistent between studies. In this work, we have re-evaluated the feasibility of using HRV for detecting drivers’ sleepiness during real road driving. A database consists of ECG measurements from 10 drivers, driving during morning, afternoon and night sessions on real road were used. Drivers have reported their average sleepiness level by using the Karolinska sleepiness scale once every five minutes. Statistical analysis was performed to evaluate the potential of HRV indexes to distinguish between alert, first signs of sleepiness and severe sleepiness states. The results suggest that individual subjects show different reactions to sleepiness, which produces an individual change in HRV indicators. The results motivate future work for more personalized approaches in sleepiness detection.

  • 5.
    Adell, Emeli
    et al.
    Trivector Traffic.
    Nilsson, Annika
    Trivector Traffic.
    Kircher, Katja
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Cyclists' use of mobile IT in Sweden: usage and self-reported behavioural compensation2014In: 3rd International Cycling Safety Conference (ICSC2014), 18-19 November, Gothenburg, Sweden: proceedings, Gothenburg, Sweden, 2014Conference paper (Refereed)
    Abstract [en]

    The increasing use of mobile phones while cycling has raised safety concerns. In this paper two studies of mobile phone use by cyclists are presented.

    The first study was designed to characterize mobile phone use by cyclists in Sweden, while the second studied how mobile phone use affected cyclist behaviour and compensation strategies. Mobile phone use was observed in about 20 percent of all urban bicycle trips. The usage varied with cyclist age with the highest usage among young cyclists. Of those using phones, 90% of the cyclists observed used head-phones.

    In parallel, standardized, interviews 15% of cyclists under 15 years old stated that they always used mobile phones while cycling. Listening to music in headphones was the most fre-quent self-reported activity. To converse using hand-held phones was also rather common, and was the only mobile phone usage reported by women above 50 years old.

    In the second study twenty-two young cyclists (age 16-25 years) completed a route in real traffic five times while listening to music, receiving and making calls, receiving and sending text messages, searching for information on the internet and while cycling normally without using the phone. The route and the types of tasks were controlled, but the cyclists could choose rather freely when, where and how to carry out the tasks. When the cyclist returned to the starting point, a short interview was conducted. During the interviews cyclists reported their experiences and the compensation strategies they used while cycling.

  • 6.
    Adell, Emeli
    et al.
    Trivector Sweden.
    Nilsson, Lena
    Swedish National Road and Transport Research Institute, Traffic and road users.
    Várhelyi, András
    Lund University.
    How Is Acceptance Measured?: Overview of Measurement Issues, Methods and Tools2014In: Driver Acceptance of New Technology: Theory, Measurement and Optimisation / [ed] Michael A. Regan, Tim Horberry and Alan Stevens, Farnham, Surrey, England: Ashgate, 2014, p. 74-88Chapter in book (Refereed)
    Abstract [en]

    This chapter describes how acceptance has been measured and identifies various measurement categories. The relationship between these measurement methods and the different definitions of acceptance appearing in the literature is described and the lack of correspondence between definition and measurement is highlighted. The chapter illustrates the different outcomes of acceptance measurements depending on choice of assessment method and gives some guidance that could be used depending on the purpose of the assessment.

  • 7.
    Adell, Emeli
    et al.
    Trivector Sweden.
    Várhelyi, András
    Lund University.
    Nilsson, Lena
    Swedish National Road and Transport Research Institute, Traffic and road users.
    Modelling Acceptance of Driver Assistance Systems: Application of the Unified Theory of Acceptance and Use of Technology2014In: Driver Acceptance of new technology: Theory, Measurement and Optimisation / [ed] Michael A. Regan, Tim Horberry and Alan Stevens, Farnham, Surrey, England: Ashgate, 2014, p. 23-34Chapter in book (Refereed)
    Abstract [en]

    This chapter provides a brief overview of acceptance models used within the area of information technology.  One particular model, the Unified Theory of Acceptance and Use of Technology (UTAUT), is then discussed, and a study is reported in which the model was used to assess driver acceptance of a particular driver assistance system. The key findings of that study are reported, and suggestions are made for refining UTAUT to make it more suitable for assessing acceptance of driver assistance systems.

     

  • 8.
    Adell, Emeli
    et al.
    Trivector Sweden.
    Várhelyi, András
    Lunds Universitet.
    Nilsson, Lena
    Swedish National Road and Transport Research Institute, Traffic and road users.
    The Definition of Acceptance and Acceptability2014In: Driver Acceptance of New Technology: Theory, Measurement and Optimisation / [ed] Michael A. Regan, Tim Horberry and Alan Stevens, Farnham, Surrey, England: Ashgate, 2014, p. 11-21Chapter in book (Refereed)
    Abstract [en]

    Despite the recognised importance of the concept of acceptance, how and why new technologies are actually accepted by drivers is not well understood. While many studies claim to have measured acceptance, few have explicitly defined what it is. This chapter points out the importance of defining acceptance and categorises definitions that have been used according to their “essence”. Distinctions between different types of acceptance as well as between acceptance and acceptability are also described. A proposal for a common definition of acceptance is then presented and discussed.

  • 9. Adesiyun, Adewole
    et al.
    Bezuglyi, Artem
    Bidnenko, Natalya
    Laszlo, Gaspar
    Golovko, Sergyi
    Kraszewski, Cezary
    Krayushkina, Kateryna
    Kushnir, Olexander
    Kuttah, Dina K
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Niska, Anna
    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, society and road-user.
    Szpikowski, Miroslaw
    Andrezj, Urbanik
    Voloshyna, Iryna
    Vozniuk, Andrii
    Vyrozhemsky, Valeriy
    Short-term Research Visits2014Report (Other (popular science, discussion, etc.))
  • 10.
    Adolph, Thorsten
    et al.
    Federal Highway Research Institute.
    Eggers, Andre
    Federal Highway Research Institute.
    Thomson, Robert William
    Swedish National Road and Transport Research Institute, Traffic and road users, Traffic safety, society and road-user.
    Mizuno, Koji
    Nagoya University.
    Comparison of the dummy response in two different restraint system crash tests2014In: 2014 IRCOBI Conference Proceedings - International Research Council on the Biomechanics of Injury, 2014, p. 545-561Conference paper (Refereed)
    Abstract [en]

    In the European Project FIMCAR, a proposal for a frontal impact test configuration was developed which included an additional full width deformable barrier (FWDB) test. Motivation for the deformable element was partly to measure structural forces as well as to produce a severe crash pulse different from that in the offset test. The objective of this study was to analyse the safety performance of vehicles:

    • in the full width rigid barrier test (FWRB) and
    • in the full width deformable barrier test (FWDB)

    In total, 12 vehicles were crashed in both configurations. Comparison of these tests to real world accident data was used to identify the crash barrier most representative of real world crashes. For all vehicles, the airbag visible times were later in the FWDB configuration. This was attributed to the attenuation of the initial acceleration peak, observed in FWRB tests, by the addition of the deformable element. These findings were in alignment with airbag triggering times seen in real world crash data. Also, the dummy loadings were slightly worse in FWDB compared to FWRB tests, which is possibly linked to the airbag firing and a more realistic loading of the vehicle crash structures in the FWDB configuration. Evaluations of the lower extremities have shown a general increasing of the tibia index with the crash pulse severity.

  • 11.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Andersson, Jan
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Anund, Anna
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Börjesson, Emma
    Scania.
    Johansson, Hanna
    Scania.
    Johnsson, Johanna
    Scania.
    Detecting sleepiness by Optalert: final report2010Report (Other academic)
    Abstract [en]

    Many crashes with heavy vehicle can be attributed to driver sleepiness or driving impairment due to sleepiness, and it is important to find methods to predict those situations and counteract this problem. The Optalert fatigue management system claims to be able to detect sleepiness. The aims of this study are to (a) evaluate if Optalert can detect sleepiness equally well as other sleepiness indicators and (b) if the data patterns obtained by Optalert correlates with these other sleepiness indicators. Twelve sleep deprived truck drivers drove for about 90 minutes in an advanced moving base truck simulator. The experimental setup, including the sleep deprivation, was designed so that the drivers should become increasingly sleepier during the trial and the intention was that they should fall asleep during the experiment.

    Four different indicators of sleepiness or driving impairment due to sleepiness were used to monitor the state of the drivers; the Karolinska Sleepiness Scale (KSS), the variability in lateral position (SDLP), the blink duration and the Optalert system. The results show that all four sleepiness indicators increased with time on task. An analysis of variance revealed that the changes were significant for KSS, blink duration and the Optalert system, and a correlation analysis showed that Optalert correlated significantly with blink duration and SDLP. However, even though these correlations were significant, they were all rather low with a maximum correlation coefficient of 0.24.

    In conclusion, the Optalert system is promising and the sleepiness rating provided by the system works at least equally well as the other three sleepiness indicators. There are some practical limitations to the system; there is no reliable threshold which can be used to determine when a driver is getting too sleepy to drive (this is also the case for other available sleepiness indicators), the driver needs to be attached to the vehicle via the spectacle frames and a wire, and the quality of the eye movement recordings often deteriorated when the driver started driving the truck. Moreover, during the experiment the technical reliability was sometimes low.

  • 12.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human Factors in the Transport System.
    Anund, Anna
    Swedish National Road and Transport Research Institute, Traffic and road users, Human Factors in the Transport System.
    Fors, Carina
    Swedish National Road and Transport Research Institute, Traffic and road users, Human Factors in the Transport System.
    Åkerstedt, Torbjörn
    Karolinska Institutet.
    Effects of the road environment on the development of driver sleepiness in young male drivers2018In: Accident Analysis and Prevention, ISSN 0001-4575, E-ISSN 1879-2057, Vol. 112, p. 127-134Article in journal (Refereed)
    Abstract [en]

    Latent driver sleepiness may in some cases be masked by for example social interaction, stress and physical activity. This short-term modulation of sleepiness may also result from environmental factors, such as when driving in stimulating environments. The aim of this study is to compare two road environments and investigate how they affect driver sleepiness. Thirty young male drivers participated in a driving simulator experiment where they drove two scenarios: a rural environment with winding roads and low traffic density, and a suburban road with higher traffic density and a more built-up roadside environment. The driving task was essentially the same in both scenarios, i.e. to stay on the road, without much interaction with other road users. A 2 x 2 design, with the conditions rural versus suburban, and daytime (full sleep) versus night-time (sleep deprived), was used. The results show that there were only minor effects of the road environment on subjective and physiological indicators of sleepiness. In contrast, there was an increase in subjective sleepiness, longer blink durations and increased EEG alpha content, both due to time on task and to night-time driving. The two road environments differed both in terms of the demand on driver action and of visual load, and the results indicate that action demand is the more important of the two factors. The notion that driver fatigue should be countered in a more stimulating visual environment such as in the city is thus more likely due to increased task demand rather than to a richer visual scenery. This should be investigated in further studies.

  • 13.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human Factors in the Transport System.
    Anund, Anna
    Swedish National Road and Transport Research Institute, Traffic and road users, Human Factors in the Transport System.
    Fors, Carina
    Swedish National Road and Transport Research Institute, Traffic and road users, Human Factors in the Transport System.
    Åkerstedt, Torbjörn
    Stockholms Universitet.
    The effect of daylight versus darkness on driver sleepiness: A driving simulator study2017In: Journal of Sleep Research, ISSN 0962-1105, E-ISSN 1365-2869Article in journal (Refereed)
    Abstract [en]

    Driver sleepiness studies are often carried out with alert drivers during daytime and sleep-deprived drivers during night-time. This design results in a mixture of different factors (e.g. circadian effects, homeostatic effects, light conditions) that may confound the results. The aim of this study was to investigate the effect of light conditions on driver sleepiness. Thirty young male drivers (23.6 ± 1.7 years old) participated in a driving simulator experiment where they drove on a rural road. A 2 × 2 design was used with the conditions daylight versus darkness, and daytime (full sleep) versus night-time (sleep deprived). The results show that light condition had an independent effect on the sleepiness variables. The subjective sleepiness measured by Karolinska Sleepiness Scale was higher, lateral position more left-oriented, speed lower, electroencephalogram alpha and theta higher, and blink durations were longer during darkness. The number of line crossings did not change significantly with light condition. The day/night condition had profound effects on most sleepiness indicators while controlling for light condition. The number of line crossings was higher during night driving, Karolinska Sleepiness Scale was higher, blink durations were longer and speed was lower. There were no significant interactions, indicating that light conditions have an additive effect on sleepiness. In conclusion, Karolinska Sleepiness Scale and blink durations increase primarily with sleep deprivation, but also as an effect of darkness. Line crossings are mainly driven by the need for sleep and the reduced alertness at the circadian nadir. Lane position is, however, more determined by light conditions than by sleepiness.

  • 14.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Bolling, Anne
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Sörensen, Gunilla
    Swedish National Road and Transport Research Institute, Traffic and road users, Traffic safety, society and road-user.
    Eriksson, Olle
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Andersson, Anders
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Validating speed and road surface realism in VTI driving simulator III2012Report (Other academic)
    Abstract [en]

    New simulator models concerning vibration, noise and graphics have been designed and implemented in the VTI Simulator III. The objective of this study is to validate this simulator in terms of road surface realism. Twenty-four drivers participated in the study and drove the same route both in the simulator and on real roads. Three road sections ranging from very smooth to rather uneven were incorporated in the design. The comparison included the objective driving parameter speed as well as subjective parameters from questionnaires and rating scales (evenness, quietness and comfort level). A road section with five speed limit changes was of particular interest in the analyses. No statistically significant difference could be found between the simulator and the car, neither in the parameter speed (in sections with no speed limit changes) nor in the ratings evenness and quietness. Despite similar speed profiles surrounding the speed limit signs, there was a statistically significant difference between the speed in the car and in the simulator, with more rapid accelerations and decelerations in the simulator. The comfort rating was shown to be higher in the car compared to the simulator, but in both cases the general trend showed higher comfort on smoother roads. These results indicate absolute validity for the ratings evenness and quietness, and for the measure speed, and relative validity for comfort and speed surrounding speed limit signs.

  • 15.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Dukic, Tania
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Comparison of eye tracking systems with one and three cameras2011In: ACM International Conference Proceeding Series, 2011Conference paper (Refereed)
    Abstract [en]

    When using eye movements to determine the state of a car driver it is important that the eye tracker is robust, unobtrusive, inexpensive and fully automatic. The objectives of this study are to compare the performance of a one-camera system with a three-camera system and to investigate if the accuracy and availability of the one-camera system is sufficient to monitor driver state. Data from 53 subjects were evaluated and the results indicate that there is not much difference between a single-camera system and a multi-camera system as long as the driver is looking straight ahead. However, with more peripheral gaze directions, the larger coverage that is provided by the additional cameras works in favour of the multi-camera system. © ACM 2010.

  • 16.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Dukic, Tania
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Ivarsson, Erik
    SmartEye.
    Kircher, Albert
    Swedish National Road and Transport Research Institute.
    Rydbeck, Bosse
    SmartEye.
    Viström, Matias
    Saab Automobile.
    Performance of a one-camera and a three-camera system2010Report (Other academic)
    Abstract [en]

    Driving and operating a vehicle is to a great extent a visual task. In driver behaviour studies it is therefore important to be able to measure where the driver is looking. Today this can be done unobtrusively and remotely in real-time with camera based eye tracking. The most common remote eye tracking systems use multiple cameras in order to give satisfactory results. However, promising results using only one camera has recently emerged on the market. The main objective of this study is to compare eye tracking systems with one and three cameras, respectively, during various measurement conditions.

    A total of 53 participants were enrolled in the study. Data from the two eye trackers were acquired and analysed in terms of availability, accuracy and precision. The results indicate that both availability and accuracy are affected by many different factors. The most important factors are the number of cameras that is used and the angular distance from straight ahead. In the central region (straight ahead) both one-camera and three-camera systems have a high degree of accuracy and availability, but with increasing distance from the central region, the results deteriorate. This effect falls harder upon the one-camera system. Interestingly, there were no significant effects when wearing glasses in either availability or accuracy. There was however an interaction effect between distance and glasses.

    Advantages with a one-camera system are that it is cheaper, easier to operate and easier to install in a vehicle. A multi-camera system will, on the other hand, provide higher availability and accuracy for areas that are far from the road centre. A one-camera system is thus mostly suitable for in-vehicle applications such as systems that warn drivers for sleepiness or distraction while multi-camera solutions are preferable for research purposes.

  • 17.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Fors, Carina
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Anund, Anna
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Hallvig, David
    Stockholms Universitet.
    Video-based observer rated sleepiness versus self-reported subjective sleepiness in real road driving2015In: European Transport Research Review, ISSN 1867-0717, E-ISSN 1866-8887, Vol. 7, no 4, article id 38Article in journal (Refereed)
    Abstract [en]

    Observer-rated sleepiness (ORS) based on video recordings of the driver’s face is often used when analysing naturalistic driving data. The aim of this study is to investigate if ORS ratings agree with subjective self-reported sleepiness (SRS).

    Forty raters assessed 54 video-clips showing drivers with varying levels of sleepiness. The video-clips were recorded during a field experiment focusing on driver sleepiness using the same cameras that are typically used in large-scale field studies. The weak results prompted a second test. Ten human factors researchers made pairwise comparisons of videos showing the same four participants in an alert versus a very sleepy condition. The task was simply to select the video-clip where the driver was sleepy.

    The overall average percentage of video segments where ORS and SRS matched was 41 % in Test 1. ORS 0 (alert) and ORS 2 (very sleepy) were easier to score than ORS 1 and it was slightly harder to rate night-time drives. Inter-rater agreement was low, with average Pearson’s r correlations of 0.19 and Krippendorff’s alpha of 0.15. In Test 2, the average Pearson’s r correlations was 0.35 and Krippendorff’s alpha was 0.62. The correspondence between ORS and SRS showed an agreement of 35 %.

    The results indicate that ORS ratings based on real road video recordings correspond poorly with SRS and have low inter-rater agreement. Further research is necessary in order to further evaluate the usefulness of ORS as a measure of sleepiness.

  • 18.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Fors, Carina
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Forward, Sonja
    Swedish National Road and Transport Research Institute, Society, environment and transport, Mobility, actors and planning processes.
    Gregersen, Nils Petter
    Swedish National Road and Transport Research Institute, Society, environment and transport, Mobility, actors and planning processes.
    Hjälmdahl, Magnus
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Jansson, Jonas
    Swedish National Road and Transport Research Institute, Traffic and road users.
    Kircher, Katja
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Lindberg, Gunnar
    Swedish National Road and Transport Research Institute, Society, environment and transport, Transport economics Stockholm.
    Nilsson, Lena
    Swedish National Road and Transport Research Institute, Traffic and road users.
    Patten, Christopher
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Dangerous use of mobile phones and other communication devices while driving: A toolbox of counter-measures2013In: Proceedings of the 16th International Conference Road Safety on Four Continents: Beijing, China. 15-17 May 2013, Linköping: Statens väg- och transportforskningsinstitut, 2013Conference paper (Other academic)
    Abstract [en]

    The use of mobile phone and similar devices while driving has been a topic of discussion and research for several years. It is now an established fact that driving performance is deteriorated due to distraction but no clear conclusions can yet be drawn concerning influence on crash rates. Better studies on this relationship is needed. Most countries in Europe and many countries elsewhere have introduced different types of bans for handheld devices. Sweden has, however, no such bans. VTI was commissioned by the Swedish Government to outline possible means to reduce the dangerous usage of mobile phones and other communication devices while driving as alternatives to banning. This task was a result of a previous VTI-state-of-the-art review of research on mobile phone and other communication device usage while driving. One of the findings in the review was that bans on handheld phones did not appear to reduce the number of crashes.

    Eighteen different countermeasures in three main areas were suggested. (1) Technical solutions such as countermeasures directed towards the infrastructure, the vehicle and the communication device. (2) Education and information, describing different ways to increase knowledge and understanding among stakeholders and different driver categories. (3) Different possibilities for how society, industry and organisations can influence the behaviour of individuals, via policies, rules, recommendations and incentives. Our conclusion is that a combination of different countermeasures is needed – where education and information to the drivers are combined with support and incentives for a safe usage of different communication devices.

  • 19.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL.
    Ihlström, Jonas
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL.
    Kircher, Katja
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL.
    Förares användning av kommunikationsutrustning under färd: Del 1: Enkätstudie. Del 2: Användning enligt objektiv mätning2017Report (Other academic)
    Abstract [sv]

    Av resultaten från denna enkät är något av det mest tydliga att saker som funnits i en bil en längre tid, exempelvis att ställa in radio, använda navigationsutrustning och prata i telefon, görs i betydligt högre utsträckning än nyare saker som att skicka meddelanden, surfa på internet eller spela spel. Överlag tycks det vara låg acceptans för de nyare företeelserna och en stor andel av urvalet tycker att det är felaktigt eller olämpligt att hålla på med dessa aktiviteter. Att prata i telefon med handsfree tycks uppfattas av många som säkrare och mer lämpligt än att inte använda det. Detta avspeglas även i inställning till införandet av förbud, där en relativt stor andel accepterar att det ska vara lagligt att använda handsfreefunktioner men att annan användning av kommunikationsutrustning borde förbjudas.

    I den andra delen genomfördes en mätning av mobilanvändning under färd genom installerande tav en mobilapp. Den genomförda undersökningen är den första av sitt slag åtminstone i Sverige, så att den, trots vissa brister och begränsningar, kan leverera information som hittills har varit okänt. I detta del diskuteras resultaten, även i förhållande till enkätsvaren, följt av en reflektion över metoden och möjliga förbättringar, som är önskvärda inför en fortsättningsstudie.

  • 20.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL.
    Jansson, Sabina
    Linköpings Universitet.
    Anund, Anna
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL.
    Local changes in the wake electroencephalogram precedes lane departures2017In: Journal of Sleep Research, ISSN 0962-1105, E-ISSN 1365-2869Article in journal (Refereed)
    Abstract [en]

    The objective of this exploratory study is to investigate if lane departures are associated with local sleep, measured via source-localized electroencephalography (EEG) theta power in the 5-9 Hz frequency range. Thirty participants drove in an advanced driving simulator, resulting in 135 lane departures at high levels of self-reported sleepiness. These lane departures were compared to matching non-departures at the same sleepiness level within the same individual. There was no correspondence between lane departures and global theta activity. However, at the local level an increased risk for lane departures was associated with increased theta content in brain regions related to motor function.

  • 21.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human Factors in the Transport System.
    Kircher, Katja
    Swedish National Road and Transport Research Institute, Traffic and road users, Human Factors in the Transport System. Linköpings Universitet.
    A Generalized Method to Extract Visual Time-Sharing Sequences From Naturalistic Driving Data2017In: IEEE transactions on intelligent transportation systems (Print), ISSN 1524-9050, E-ISSN 1558-0016, Vol. 18, no 11, p. 2929-2938Article in journal (Refereed)
    Abstract [en]

    Indicators based on visual time-sharing have been used to investigate drivers' visual behaviour during additional task execution. However, visual time-sharing analyses have been restricted to additional tasks with well-defined temporal start and end points and a dedicated visual target area. We introduce a method to automatically extract visual time-sharing sequences directly from eye tracking data. This facilitates investigations of systems, providing continuous information without well-defined start and end points. Furthermore, it becomes possible to investigate time-sharing behavior with other types of glance targets such as the mirrors. Time-sharing sequences are here extracted based on between-glance durations. If glances to a particular target are separated by less than a time-based threshold value, we assume that they belong to the same information intake event. Our results indicate that a 4-s threshold is appropriate. Examples derived from 12 drivers (about 100 hours of eye tracking data), collected in an on-road investigation of an in-vehicle information system, are provided to illustrate sequence-based analyses. This includes the possibility to investigate human-machine interface designs based on the number of glances in the extracted sequences, and to increase the legibility of transition matrices by deriving them from time-sharing sequences instead of single glances. More object-oriented glance behavior analyses, based on additional sensor and information fusion, are identified as the next future step. This would enable automated extraction of time-sharing sequences not only for targets fixed in the vehicle's coordinate system, but also for environmental and traffic targets that move independently of the driver's vehicle.

  • 22.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL.
    Kircher, Katja
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL. Linköping University.
    Changes in glance behaviour when using a visual eco-driving system: A field study2017In: Applied Ergonomics, ISSN 0003-6870, E-ISSN 1872-9126, Vol. 58, p. 414-423Article in journal (Refereed)
    Abstract [en]

    While in-vehicle eco-driving support systems have the potential to reduce greenhouse gas emissions and save fuel, they may also distract drivers, especially if the system makes use of a visual interface. The objective of this study is to investigate the visual behaviour of drivers interacting with such a system, implemented on a five-inch screen mounted above the middle console. Ten drivers participated in a real-world, on-road driving study where they drove a route nine times (2 pre-baseline drives, 5 treatment drives, 2 post-baseline drives). The route was 96 km long and consisted of rural roads, urban roads and a dual-lane motorway.

    The results show that drivers look at the system for 5–8% of the time, depending on road type, with a glance duration of about 0.6 s, and with 0.05% long glances (>2s) per kilometre. These figures are comparable to what was found for glances to the speedometer in this study. Glance behaviour away from the windscreen is slightly increased in treatment as compared to pre- and post-baseline, mirror glances decreased in treatment and post-baseline compared to pre-baseline, and speedometer glances increased compared to pre-baseline. The eco-driving support system provided continuous information interspersed with additional advice pop-ups (announced by a beep) and feedback pop-ups (no auditory cue). About 20% of sound initiated advice pop-ups were disregarded, and the remaining cases were usually looked at within the first two seconds. About 40% of the feedback pop-ups were disregarded. The amount of glances to the system immediately before the onset of a pop-up was clearly higher for feedback than for advice.

  • 23.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kircher, Katja
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Review of real-time visual driver distraction detection algorithms2011In: ACM International Conference Proceeding Series, 2011Conference paper (Refereed)
    Abstract [en]

    Many incidents and crashes can be attributed to driver distraction, and it is essential to learn how to detectdistraction in order to develop efficient countermeasures. A number of distraction detection algorithms have been developed over the years, and the objective of this paper is to summarize available approaches and to describe these algorithms in a unified framework. The review is limited to real-time algorithms that are intended to detect visual distraction.

  • 24.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kircher, Katja
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Fors, Carina
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Dukic, Tania
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Patten, Christopher
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Anund, Anna
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Measuring driver impairments: Sleepiness, distraction, and workload2012In: IEEE Pulse, ISSN 2154-2287, Vol. 3, no 2, p. 22-30Article in journal (Refereed)
    Abstract [en]

    Snow was falling heavily when Sarah was driving on a slippery road to her cousin’s country cottage. It was dark outside, and the visibility was poor. She had planned to arrive before sunset, but the rental service had made a mistake, and it took hours before she got her rental car at the airport. It was past midnight now, and after a long day of traveling, Sarah was starting to get sleepy.

    Fortunately, there were only 15 km to go, but her eyelids were starting to feel heavy. To stay awake, she put her favorite CD on, turned up the volume, and started to sing along. This seemed to help a little -good- only 10 km to go. This was when Sarah’s phone started ringing, and she awkwardly tried to find the mute button for the car stereo while answering the phone. As she looked up again, she barely caught a glimpse of the red brake lights of the car in front of her as she smashed into it.

  • 25.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kircher, Katja
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kircher, Albert
    Linköpings Universitet.
    A gaze-based driver distraction warning system and its effect on visual behaviour2013In: IEEE transactions on intelligent transportation systems (Print), ISSN 1524-9050, E-ISSN 1558-0016, Vol. 14, no 2, p. 965-973Article in journal (Refereed)
    Abstract [en]

    Driver distraction is a contributing factor to many crashes; therefore, a real-time distraction warning system should have the potential to mitigate or circumvent many of these crashes. The objective of this paper is to investigate the usefulness of a real-time distraction detection algorithm called AttenD. The evaluation is based on data from an extended field study comprising seven drivers who drove on an average of 4351 ± 2181 km in a naturalistic setting.

    Visual behavior was investigated both on a global scale and on a local scale in the surroundings of each warning. An increase in the percentage of glances at the rear-view mirror and a decrease in the amount of glances at the center console were found. The results also show that visual time sharing decreased in duration from 9.94 to 9.20 s due to the warnings, that the time from fully attentive to warning decreased from 3.20 to 3.03 s, and that the time from warning to full attentiveness decreased from 6.02 to 5.46 s. The limited number of participants does not allow any generalizable conclusions, but a trend toward improved visual behavior could be observed. This is a promising start for further improvements of the algorithm and the warning strategy.

  • 26.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kircher, Katja
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kircher, Albert
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Considerations when calculating percent road centre from eye movement data in driver distraction monitoring2009In: Proceedings of the Fifth International Driving Symposium on Human Factors in Driver Assessment, Training and Vehicle Design, 2009, p. 132-139Conference paper (Refereed)
    Abstract [en]

    Percent road center (PRC) is a performance indicator which is sensitive to driver distraction. The original definition of PRC is based on fixation data extracted from eye movement recordings, but it has also been suggested that PRC can be determined directly from the gaze data without segmenting it into saccades and fixations. The primary aim of this paper is to investigate if this is the case.

    Naturalistic driving data from a small scale field operational test comprising seven vehicles was used in the evaluation. It was found that PRC time traces based on gaze data and fixation data, respectively, were highly similar (correlation coefficient=0.95, average wavelet semblance=0.84) except for an absolute amplitude difference of about 8%. This indicates that the two approaches can be used interchangeably and that the processing step of segmenting gaze data into saccades and fixations can be left out.

    In addition to this finding, design issues related to the calculation of PRC are investigated. Especially, the impact of gaze cases pointing towards the intersection of the road centre area and the centre rear mirror were investigated. Results lead to conclude that gazes and fixations on the centre rear mirror should be removed from the PRC calculations, as they may negatively influence the correctness of the performance indicator.

  • 27.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kircher, Katja
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Rydström, Annie
    Volvo Car Corperation.
    Nåbo, Arne
    SAAB Automobile.
    Almgren, Susanne
    SAAB Automobile.
    Ricknäs, Daniel
    Scania.
    Effects of visual, cognitive and haptic tasks on driving performance indicators2012In: Advances in Human Aspects of Road and Rail Transportation / [ed] Neville A . Stanton, San Francisco, USA: CRC Press , 2012, p. 673-682Conference paper (Refereed)
    Abstract [en]

    A driving simulator study was conducted by using the same setup in two driving simulators, one with a moving base and one with a fixed base. The aim of the study was to investigate a selection of commonly used performance indicators (PIs) for their sensitivity to secondary tasks loading on different modalities and levels of difficulty, and to evaluate their robustness across simulator platforms. The results showed that, across platforms, the longitudinal PIs behaved similarly whereas the lateral control and eye movement based performance indicators differed. For modality, there were considerable effects on lateral, longitudinal as well as eye movement PIs. However, there were only limited differences between the baseline and the cognitive and haptic tasks. For difficulty, clear effects on PIs related to lateral control and eye movements were shown. Additionally, it should be noted that there were large individual differences for several of the PIs. In conclusion, many of the most commonly used PIs are susceptible to individual differences, and, especially the PIs for lateral control, to the platform and environment where they are acquired, which is why generalizations should be made with caution.

  • 28.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kircher, Katja
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Thorslund, Birgitta
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Adell, Emeli
    Trivector Traffic.
    Bicyclists’ visual strategies when conducting self-paced vs. system-paced smartphone tasks in traffic2015In: Transportation Research Part F: Traffic Psychology and Behaviour, ISSN 1369-8478, E-ISSN 1873-5517, Vol. 41, p. 204-216Article in journal (Refereed)
    Abstract [en]

    Visual distraction among cyclists interacting with their mobile phones is a growing concern. Yet, very little research has actually investigated how cyclists apply visual strategies and adapt task execution depending on the traffic situation. The aim of this study is to investigate visual behaviour of cyclists when conducting self-paced (initiated by the cyclist) vs. system-paced (initiated by somebody else) smartphone tasks in traffic. Twenty-two cyclists completed a track in real traffic while listening to music, receiving and making calls, receiving and sending text messages, and searching for information on the internet. The route and the types of tasks were controlled, but the cyclists could choose rather freely when and where along the route to carry out the tasks, thus providing semi-naturalistic data on compensatory behaviour. The results show that the baseline and music conditions were similar in terms of visual behaviour. When interacting with the phone, it was found that glances towards the phone mostly came at the expense of glances towards traffic irrelevant gaze targets and also led to shortened glance durations to traffic relevant gaze targets, while maintaining the number of glances. This indicates that visual “spare capacity” is used for the execution of the telephone tasks. The task type influenced the overall task duration and the overall glance intensity towards the phone, but not the mean nor maximum duration of individual glances. Task pacing was the factor that influenced visual behaviour the most, with longer mean and maximum glance durations for self-paced tasks. In conclusion, the cyclists used visual strategies to integrate the handling of mobile phones into their cycling behaviour. Glances directed towards the phone did not lead to traffic relevant gaze targets being missed. In system-paced scenarios, the cyclists checked the traffic more frequently and intensively than in self-paced tasks. This leads to the assumption that cyclists prepare for self-initiated tasks by for example choosing a suitable location. Future research should investigate whether these strategies also exists amongst drivers and other road user groups.

  • 29.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Nyström, Marcus
    Lunds Universitet.
    Holmqvist, Kenneth
    Lunds Universitet.
    Fors, Carina
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Sandberg, David
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Anund, Anna
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kecklund, Göran
    Stockholms Universitet.
    Ņkerstedt, Torbjörn
    Stockholms Universitet.
    Fit-for-duty test for estimation of drivers’ sleepiness level: Eye movements improve the sleep/wake predictor2013In: Transportation Research Part C: Emerging Technologies, ISSN 0968-090X, E-ISSN 1879-2359, Vol. 26, p. 20-32Article in journal (Refereed)
    Abstract [en]

    Driver sleepiness contributes to a considerable proportion of road accidents, and a fit-for-duty test able to measure a driver’s sleepiness level might improve traffic safety. The aim of this study was to develop a fit-for-duty test based on eye movement measurements and on the sleep/wake predictor model (SWP, which predicts the sleepiness level) and evaluate the ability to predict severe sleepiness during real road driving. Twenty-four drivers participated in an experimental study which took place partly in the laboratory, where the fit-for-duty data were acquired, and partly on the road, where the drivers sleepiness was assessed. A series of four measurements were conducted over a 24-h period during different stages of sleepiness. Two separate analyses were performed; a variance analysis and a feature selection followed by classification analysis. In the first analysis it was found that the SWP and several eye movement features involving anti-saccades, pro-saccades, smooth pursuit, pupillometry and fixation stability varied significantly with different stages of sleep deprivation. In the second analysis, a feature set was determined based on floating forward selection. The correlation coefficient between a linear combination of the acquired features and subjective sleepiness (Karolinska sleepiness scale, KSS) was found to be R=. 0.73 and the correct classification rate of drivers who reached high levels of sleepiness (KSS ≥ 8) in the subsequent driving session was 82.4% (sensitivity = 80.0%, specificity = 84.2% and AUC = 0.86). Future improvements of a fit-for-duty test should focus on how to account for individual differences and situational/contextual factors in the test, and whether it is possible to maintain high sensitive/specificity with a shorter test that can be used in a real-life environment, e.g. on professional drivers. © 2012 Elsevier Ltd.

  • 30.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Victor, Trent
    Chalmers University of Technology.
    Wege, Claudia
    Steinmetz, Erik
    SP Technical Research Institute Sweden.
    Processing of eye/head-tracking data in large-scale naturalistic driving data sets2012In: IEEE transactions on intelligent transportation systems (Print), ISSN 1524-9050, E-ISSN 1558-0016, Vol. 13, no 2, p. 553-564Article in journal (Refereed)
    Abstract [en]

    Driver distraction and driver inattention are frequently recognized as leading causes of crashes and incidents. Despite this fact, there are few methods available for the automatic detection of driver distraction. Eye tracking has come forward as the most promising detection technology, but the technique suffers from quality issues when used in the field over an extended period of time. Eye-tracking data acquired in the field clearly differs from what is acquired in a laboratory setting or a driving simulator, and algorithms that have been developed in these settings are often unable to operate on noisy field data. The aim of this paper is to develop algorithms for quality handling and signal enhancement of naturalistic eye- and head-tracking data within the setting of visual driver distraction. In particular, practical issues are highlighted. Developed algorithms are evaluated on large-scale field operational test data acquired in the Sweden-Michigan Field Operational Test (SeMiFOT) project, including data from 44 unique drivers and more than 10000 trips from 13 eye-tracker-equipped vehicles. Results indicate that, by applying advanced data-processing methods, sensitivity and specificity of eyes-off-road glance detection can be increased by about 10%. In conclusion, postenhancement and quality handling is critical when analyzing large databases with naturalistic eye-tracking data. The presented algorithms provide the first holistic approach to accomplish this task. © 2011 IEEE.

  • 31. Aigner-Breuss, Eva
    et al.
    Pilgerstorfer, Monika
    Anund, Anna
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Dukic, Tania
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Chalkia, Eleni
    Ferrarini, Chiara
    Montanari, Roberto
    Wacowska, Justyna
    Jankowska, Dagmara
    Diederichs, Frederik
    Pauzie, Annie
    Comparison and analysis of user and stakeholder needs across different countries2010Report (Other academic)
    Abstract [en]

    The current deliverable aims at presenting the results of the analysis of stakeholder needs, in order to have support for selecting the most relevant use cases. For the identification of user requirements of all stakeholders relevant to school transportation different methods were used:

    - Focus groups with representatives of one user or stakeholder group

    - Workshops with different stakeholders

    - 2 questionnaire surveys (Questionaire A: Road Experts, Questionaire B: children, parents and bus drivers)

    Problems and needs in the following areas were subject of discussions, interviews and questionnaires:

    - Behaviour of road users counteracting with school buses

    - Behaviour of pupils on the school bus and while entering and exiting the same

    - Design of bus stops

    - Protection of pupils on the school bus

    - Condition of school buses

    - Education of school bus drivers

    - Education of pupils concerning school transportation

    - Information flow

    - Route to/from school

    - Special needs of children with disabilities

    Results show that the organisation of school transport varies between countries and even within a country. Stakeholders underline the importance of consistent regulations and clear responsibilities as a basis for a safe way to school by bus.

  • 32. Albertsson, Pontus
    et al.
    Linder, Astrid
    Swedish National Road and Transport Research Institute, Traffic and road users, Traffic safety, society and road-user.
    Evaluation of extrication techniques. - Is there any other quality measurement then time?2007Conference paper (Refereed)
  • 33.
    Albinsson, Anton
    et al.
    Chalmers Tekniska Högskola.
    Bruzelius, Fredrik
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation. Chalmers Tekniska Högskola.
    Jacobson, Bengt
    Chalmers Tekniska Högskola.
    Jonasson, Mats
    Volvo Cars Cooperation.
    Tire Force Estimation Based on the Recursive Least Square Method Utilizing Wheel Torque Measurement2014Conference paper (Refereed)
    Abstract [en]

    This study investigates a new tire force estimator based on the recursive least square (RLS) method. Tire force estimation with known driving wheel torque is studied and compared to the case with torque estimation from the internal combustion engine. This is motivated by a future scenario with electric propulsion, which reasonably gives improved wheel torque estimations. Sensitivity to vehicle parameters and challenges with individual lateral tire force estimation are also investigated. The results, experimental and simulation data, show good performance and potential for tire force estimation using the RLS method.

  • 34.
    Albinsson, Anton
    et al.
    Chalmers Tekniska Högskola.
    Bruzelius, Fredrik
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation. Chalmers Tekniska Högskola.
    Pettersson, Pierre
    BorgWarner TorqTransfer Systems,.
    Jonasson, Mats
    Kungliga Tekniska Högskolan.
    Jacobson, Bengt
    Chalmers Tekniska Högskola.
    Estimation of the inertial parameters of vehicles with electric propulsion2015In: Proceedings of the Institution of mechanical engineers. Part D, journal of automobile engineering, ISSN 0954-4070, E-ISSN 2041-2991, p. 1-18, article id 0954-4070Article in journal (Refereed)
    Abstract [en]

    More accurate information about the basic vehicle parameters can improve the dynamic control functions of a vehicle. Methods for online estimation of the mass, the rolling resistance, the aerodynamic drag coefficient, the yaw inertia and the longitudinal position of the centre of gravity of an electric hybrid vehicle is therefore proposed. The estimators use the standard vehicle sensor set and the estimate of the electric motor torque. No additional sensors are hence required and no assumptions are made regarding the tyre or the vehicle characteristics. Consequently, all information about the vehicle is available to the estimator.

    The estimators are evaluated using both simulations and experiments. Estimations of the mass, the rolling resistance and the aerodynamic drag coefficient are based on a recursive least-squares method with multiple forgetting factors. The mass estimate converged to within 3% of the measured vehicle mass for the test cases with sufficient excitation that were evaluated. Two methods to estimate the longitudinal position of the centre of gravity and the yaw inertia are also proposed. The first method is based on the equations of motion and was found to be sensitive to the measurement and parameter errors. The second method is based on the estimated mass and seat-belt indicators.

    This estimator is more robust and reduces the estimation error in comparison with that obtained by assuming static parameters. The results show that the proposed method improves the estimations of the inertial parameters. Hence, it enables online non-linear tyre force estimators and tyre-model-based tyre–road friction estimators to be used in production vehicles.

  • 35. Alten, Karoline
    et al.
    Deix, Stefan
    Peelen, Willy
    Wessels, Jos
    Courage, Wim
    Ravnikar Turk, Mojca
    Skaric Palic, Sandra
    Acalin, Nina
    Lundkvist, Sven-Olof
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Asset service condition assessment methodology (ASCAM Project)2012In: EPAM 2012, Malmö, Sweden, 5–7 September: 4th European pavement and asset management conference, Linköping: Statens väg- och transportforskningsinstitut, 2012, , p. 12Conference paper (Other academic)
    Abstract [en]

    Allocating financial resources among different sub-assets of a country’s road infrastructure is a challenge that is highly dependent on the strategic priorities and organisational structure of the infrastructure operator. While some agencies in Europe deal with pavements, bridges, tunnels or road furniture completely independently, others find that they have one mutual budget that needs to be shared out among the different assets in a way that represents their respective need for maintenance. The criteria upon which such allocations are based may be political, empirical, or based on stakeholder/user interests. The goal of the project ASCAM – Asset Service Condition Assessment Methodology – was to develop a framework for cross-asset management that can be used to objectively assign a budget to certain assets. While previous research projects have already compiled lists of various key performance indicators, ASCAM aimed to find mutual indices such as an “end user service level” that could be used to judge all sub-assets on equal terms and thus compare their condition on the same scale.

    By looking at asset management in the ASCAM partner countries and other European road agencies, the best-practice in individual asset management was extracted to develop the framework and perform a proof-of-concept for the project. While other projects such as PROCROSS within the same ERA-NET call also worked on cross-asset management – but from a top-down approach – ASCAM’s bottom-up approach looked at the more technical aspects of evaluating infrastructure condition and making a budgetary assignment based on the current and predicted state of the assets.

  • 36.
    Amantini, Aladino (ed)
    et al.
    Kite.
    Hjälmdahl, Magnus
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Lai, Frank
    ITS, University of Leeds.
    Enjalbert, Simon
    UNIVAL.
    Shinar, David
    BGU.
    Hasewinkel, Håkan
    Chalmers.
    Kircher, Albert
    Chalmers.
    Lützhöft, Margareta
    Chalmers.
    Kecklund, Lena
    MTOP.
    Initial plan of dissemination and use of results2009Report (Other academic)
    Abstract [en]

    This document contains the initial plan for using and disseminating knowledge and foreground developed within the ITERATE Project.

    The Deliverable contains five main Chapters and an Appendix.

    The first Chapter describes the purpose of the document, its structure, and introduces the other sections. Chapter 2 and 3 define the dissemination strategy of the ITERATE project and provide a classification of dissemination activities. For each type of dissemination action, the corresponding implementation approach is proposed. Then, for each type of dissemination activity, the actions already performed and those planned are described in some details. The dissemination materials already produced by the project and their usage are briefly described. Materials and products already completed, as well as planned, are described, even though a dedicated Deliverable is foreseen in the future that will contain copies of the actual products provided for dissemination purposes. The Exploitation plan is discussed in the last Chapter of the Deliverable. The two different natures and typology of partners , i.e., academic and industrial/consultancy, are considered. In particular, for each partner, a market and competition analysis is performed and the objectives and guidelines for subsequent exploitation of the results is preliminarily discussed. Finally, the appendix contains, for completeness, the Dissemination and Exploitation Questionnaire utilised to collect information among partners.

  • 37.
    Andersson, Anders
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Körsimulering och visualisering, SIM.
    Andersson Hultgren, Jonas
    Swedish National Road and Transport Research Institute, Traffic and road users, Körsimulering och visualisering, SIM.
    Leandertz, Rickard
    HiQ.
    Johansson, Martin
    Pitch Technologies.
    Betnér, Steve
    Pitch Technologies.
    Jakobson, Ola
    Volvo Car Corporation.
    Rolff, Fredrik
    Volvo Car Corporation.
    SimArch 2: Implementation and demonstration of the SimArch architecture2017Report (Other academic)
    Abstract [en]

    Complexity in modern vehicles consists of an increasingly large multitude of components that operate together. While functional verification of individual components is important, it is also important to test systems of interacting components within a driving environment, both from a functional perspective and from a driver perspective. One proven way for testing is vehicle simulators and in this work the main goals have been to increase flexibility and scalability by introducing a distributed driving simulator platform. 

    A distributed simulation architecture was designed and implemented, based on user needs defined in a previous project, which divides a driving simulator environment into four major entities with well-defined interfaces. These entities are Session Control, Environment Simulator, Driving Simulator and Vehicle simulator. High Level Architecture (HLA) Evolved, an IEEE standard, was chosen as the standard for communication. HLA Evolved is based on a publish-subscribe architecture, and is commonly used for distributed simulations. The entities and the communication topology are described in detail in the report.

    The evaluation of the distributed simulation architecture focused on flexibility and scalability, and on timing performance. Results show that the implemented distributed simulation architecture compared to the non-modified architecture increased flexibility and scalability, as several distributed setups were tested successfully. However, it also has an inherent communication latency due to packaging and sending of data between entities, which was estimated to be one millisecond. This is an effect which needs to be considered for a distributed simulation. Especially if the communication between the Driving Simulator and the Vehicle Simulator is sensitive to such delays. During evaluations of the distributed simulation architecture, the Driving Simulator and the Vehicle Simulator were always located at one site in a low latency configuration.

  • 38.
    Andersson, Anders
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Andersson Hultgren, Jonas
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Leandertz, Rickard
    HiQ.
    Johansson, Martin
    Pitch Technologies.
    Eriksson, Steve
    Pitch Technologies.
    Jakobson, Ola
    Volvo Car Corporation.
    A Driving Simulation Platform using Distributed Vehicle Simulators and HLA2015In: Proceedings of the DSC 2015 Europe: Driving Simulation Conference & Exhibition, 2015, p. 123-130Conference paper (Refereed)
    Abstract [en]

    Modern vehicles are complex systems consisting of an increasing large multitude of components that operate together. While functional verification on individual components is important, it is also important to test components within a driving environment, both from a functional perspective and from a driver perspective. One proven way for testing is vehicle simulators and in this work the main goals have been to increase flexibility and scalability by introducing a distributed driving simulator platform.

    As an example, consider a workflow where a developer can go from a desktop simulation to an intermediate driving simulator to a high fidelity driving simulator with Hardware-In-the-Loop systems close to a finished vehicle in an easy way. To accomplish this, a distributed simulation architecture was designed and implemented that divides a driving simulator environment into four major entities with well-defined interfaces, using HLA as the method of communication. This platform was evaluated on two aspects, flexibility/scalability and timing performance. Results show that increased flexibility and scalability was achieved when using a distributed simulation platform. It is also shown that latency was only slightly increased when using HLA.

  • 39.
    Andersson, Anders
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Buffoni, Lena
    IDA, Linköping University.
    Powertrain Model Assesment for Different Driving Tasks through Requirement Verification2016In: Proceedings of the 9th EUROSIM Congress on Modelling and Simulation, 2016Conference paper (Refereed)
    Abstract [en]

    For assessing whether a system model is a good candidate for a particular simulation scenario or choosing the best system model between multiple design alternatives it is important to be able to evaluate the suitability of the system model. In this paper we present a methodology based on finite state machine requirements verifying system behavior in a Modelica environment where the intended system model usage is within a moving base driving simulator. A use case illustrate the methodology with a Modelica powertrain system model using replaceable components and measured data from a Golf V. The achieved results show the importance of context of requirements and how users are assisted in finding system model issues.

  • 40.
    Andersson, Anders
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Fritzson, Peter
    Linköping University.
    Models for Distributed Real-Time Simulation in a Vehicle Co-Simulator Setup2013In: Proceedings of the 5th International Workshop on Equation-Based Object-Oriented Modeling Languages and Tools / [ed] Henrik Nilsson, Linköping: Linköping University Electronic Press, 2013, p. 131-139Conference paper (Refereed)
    Abstract [en]

    A car model in Modelica has been developed to be used in a new setup for distributed real-time simulation where a moving base car simulator is connected with a real car in a chassis dynamometer via a 500m fiber optic communication link. The new co-simulator set-up can be used in a number of configurations where hardware in the loop can be interchanged with software in the loop. The models presented in this paper are the basic blocks chosen for modeling the system in the context of a distributed real-time simulation, estimating parameters for the powertrain model, the choice of numeric solver, and the interaction with the solver for real-time properties.

  • 41.
    Andersson, Anders
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Genell, Anders
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    SIREN: sound generation for vehicle simulation2013Report (Other academic)
    Abstract [en]

    The ViP Simulator Sound Renderer (SIREN) software has been created as a means to facilitate generation and playback of audio signals in driving simulators. Siren is a modular, scalable program with a plug-in based infrastructure. The included plug-ins offer sound file playback, sound stream playback and spatialization possibilities. Required additional functionality can be added by creating custom plug-ins. Siren by default relies on the OpenAL library for spatialization and on Csound for sound stream generation. Other spatialization and generation software can be used by replacing the corresponding API modules. Siren is implemented in the new Simulator IV as well as in Simulator III at VTI and will also be implemented in Simulator II in the immediate future. Experimental implementations have been tested in the VTI Foerst simulator running solely under the Microsoft Windows operating system. Volvo Trucks has a trial version implemented in their simulator and has made some local customization. The current sound models implemented through Siren in the VTI simulators consist of real-time synthesis of sound based on measurements performed in real vehicles (car and truck) on the Volvo test track. The resulting sound has been validated through corresponding measurements performed inside the simulator cabins as well as through informal listening by experienced drivers.

  • 42.
    Andersson, Anders
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Jansson, Jonas
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    A Moving Base Simulator Investigation of Effects of a Yaw Stability System Caused by a Side Impact2011In: Journal of Computing and Information Science in Engineering, ISSN 1530-9827, E-ISSN 1944-7078, Vol. 11, no 4, article id 044501Article in journal (Refereed)
    Abstract [en]

    The main objective of this study was to investigate how an electronic stability control (ESC) system may aid the driver in a critical sideswipe accident. Another objective was to investigate the possibility of having a realistic simulation of a sideswipe accident in a large moving base simulator. The experiment can be divided into two parts. In part one, the driver is unaware of the sudden side impact and in part two, the side impact was repeated six times.

    The experiment was driven by 18 persons. With the ESC system active no driver lost control, while with the system inactive there were five drivers that lost control in part one. In part two, the ESC system showed to stabilize the vehicle faster, and the improvement in stabilization time was between 40% and 62%. It was also seen that 2% loss of control occurred with an ESC system active and 45% without.

  • 43.
    Andersson, Anders
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Kharrazi, Sogol
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    A Framework for Credibility Assessment of a Powertrain Model in Driving Simulator Studies2016In: Proceedings of the 36th FISITA World Automotive Congress, 2016Conference paper (Refereed)
    Abstract [en]

    When performing a driving simulator study, validity of the vehicle model for the intended driving task is of key importance; otherwise, the reliability of the study results might be jeopardized. In this paper a framework for real-time credibility assessment of the simulated longitudinal dynamics by a powertrain model in a moving base driving simulator is presented. The framework consists of the physical system model and a quality model which run in parallel in real time. The developed framework has been evaluated by offline simulations, as well as in real-time in a moving base driving simulator. The evaluation results showed that the developed framework can accurately capture the validity of the powertrain model in different driving conditions and provide the credibility level of the simulation results to the simulator operator in real-time.

  • 44.
    Andersson, Anders
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Kharrazi, Sogol
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Lind, Simon
    Myklebust, Andreas
    Linköpings Universitet.
    Parameterization procedure of a powertrain model for a driving simulator2016In: Advances in Transportation Studies, ISSN 1824-5463, Vol. 1, p. 99-112Article in journal (Refereed)
    Abstract [en]

    The automotive industry is facing a major challenge to reduce environmental impacts. As a consequence, the increasing diversity of powertrain configurations put a demand on testing and evaluation procedures. One of the key tools for this purpose is simulators. In this paper a powertrain model and a procedure for parameterizing it, using chassis dynamometers and a developed pedal robot are presented. The parameterizing procedure uses the on-board diagnostics of the car and does not require any additional invasive sensors.

    Thus, the developed powertrain model and parameterization procedure provide a rapid non- invasive way of modelling powertrains of test cars. The parameterizing procedure has been used to model a front wheel drive Golf V with a 1.4L multi-fuel engine and a manual gearbox. The achieved results show a good match between simulation results and test data. The powertrain model has also been tested in real-time in a driving simulator.

  • 45.
    Andersson, Anders
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Kharrazi, Sogol
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Lind, Simon
    Myklebust, Andreas
    Parameterization Procedure of a Powertrain Model for a Driving Simulator2015In: Proceedings  of the 2015 Road Safety & Simulation International Conference, 2015Conference paper (Refereed)
    Abstract [en]

    The automotive industry is facing a major challenge to reduce environmental impacts. As a consequence, the increasing diversity of powertrain configurations put a demand on testing and evaluation procedures. One of the key tools for this purpose is simulations.

    In this paper a powertrain model and a procedure for parameterizing it, using chassis dynamometers and a developed pedal robot are presented. The parameterizing procedure uses the on-board diagnostics of the car and does not require any additional invasive sensors. Thus, the developed powertrain model and parameterization procedure provide a rapid non-invasive way of modelling powertrains of test cars. The parameterizing procedure has been used to model a front wheel drive Golf V with a 1.4L multi-fuel engine and a manual gearbox. The achieved results show a good match between simulation results and test data. The powertrain model has also been tested in real-time in a driving simulator.

  • 46.
    Andersson, Anders
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Driving Simulation and Visualization.
    Lidström, Mats
    Peters, Björn
    Swedish National Road and Transport Research Institute, Traffic and road users, Driver and vehicle.
    Rosberg, Tomas
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Thorslund, Birgitta
    Swedish National Road and Transport Research Institute, Traffic and road users, Driver and vehicle.
    Framtagning av loktågsmodell för VTI:s tågsimulator2017Report (Other academic)
    Abstract [en]

    Allowing higher speeds for freight trains would provide opportunities for a higher prioritization in the traffic flow by rail traffic management, which in itself is a capacity gain and should generate better flows and higher capacity on the Swedish rail network, especially on the major railways. Simulators are an effective and safe way to investigate the effects of changes in both driver behavior and capacity.

    The purpose of this project was to create capacity-enhancing opportunities and actions by developing a freight train simulator and investigating its possible application areas. The aim of the project was to provide a freight train simulator, consisting of a locomotive and a number of wagons, which can be used in studies to increase capacity through, for example, optimized speed, and thus changing braking profiles, for long trains. The project has delivered knowledge of new test methods, a freight train simulator and a software platform for further testing.

    The project was conducted in three successive stages. In the first phase, a pilot study was carried out with drivers, operators and problem owners, who gave the researchers an understanding of the driving environment. In addition, some of the data needed for the development of the freight train simulator was collected. In the second phase, a freight train (software and hardware) model was developed. Stage three was a validation study together with drivers.

    A Traxx model driver console was purchased from a German manufacturer. The vehicle model was developed from a single unit, Regina type (motorcar train), into a combination of several units. The train in the simulator consists of one or more locomotives and a number of wagons with a total length of up to 750 meters. A locomotive of Traxx model is used. For each device, locomotive and wagon, data is required: length, weight, load, brake, roll and air resistance. In addition, information about noise, driving, braking (re-electrical braking and conventional pneumatic brake) (P-brake), cab equipment and more are added. Currently, the track between Falköping - Jönköping - Forserum is modelled and will be used for ATC trains. The model is configurable using combinations of a locomotive (Traxx) and, currently, four different types of wagons. These can be linked in different combinations.

    Some applications that were discussed at the start of the project were, on the one side, those that could naturally be linked to longer and heavier trains, and, on the other, the ideas that arose because of the equipment purchased. At the Transport Administration winter meeting, a workshop was conducted where further uses were discussed. Among these are applications within education, energy efficient driving or design. Education and certain types of studies could be performed with the existing locomotive model, while others require either validation of parameters or some further development of the model.

    The project has provided knowledge of new test methods, this research report and a product in the form of a freight train simulator and software platform for further testing. The project has also delivered a national resource of simulator software. The software provides for cost-effective testing activities in the freight train domain. A freight train simulator has been developed, which will be valuable as a demonstration tool as well as a platform for training,

  • 47.
    Andersson, Anders
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Nyberg, Peter
    Linköpings universitet.
    Sehammar, Håkan
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Öberg, Per
    Linköpings universitet.
    Vehicle Powertrain Test Bench Co-Simulation with a Moving Base Simulator Using a Pedal Robot2013In: SAE International Journal of Passenger Cars - Electronic and Electrical Systems, ISSN 1946-4614, Vol. 6, no 1, p. 169-179Article in journal (Refereed)
    Abstract [en]

    To evaluate driver perception of a vehicle powertrain a moving base simulator is a well-established technique. We are connecting the moving base simulator Sim III, at the Swedish National Road and Transport Research Institute with a newly built chassis dynamometer at Vehicular Systems, Linköping University.

    The purpose of the effort is to enhance fidelity of moving base simulators by letting drivers experience an actual powertrain. At the same time technicians are given a new tool for evaluating powertrain solutions in a controlled environment.

    As a first step the vehicle model from the chassis dynamometer system has been implemented in Sim III. Interfacing software was developed and an optical fiber covering the physical distance of 500 m between the facilities is used to connect the systems. Further, a pedal robot has been developed that uses two linear actuators pressing the accelerator and brake pedals. The pedal robot uses feedback loops on accelerator position or brake cylinder pressure and is controlled via an UDP interface.

    Results from running the complete setup showed expected functionality and we are successful in performing a driving mission based on real road topography data. Vehicle acceleration and general driving feel was perceived as realistic by the test subjects while braking still needs improvements. The pedal robot construction enables use of a large set of cars available on the market and except for mounting the brake pressure sensor the time to switch vehicle is approximately 30 minutes.

  • 48.
    Andersson Hultgren, Jonas
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Blissing, Björn
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Jansson, Jonas
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Effects of motion parallax in driving simulators2012In: Proceedings of the Driving Simulation Conference Europe 2012, 2012Conference paper (Refereed)
    Abstract [en]

    Motion parallax due to the driver’s head movement have been implemented and tested in VTI Driving Simulator III. An advanced camera-based system was used to track the head movements of the driver. The output from the tracking system was fed to the simulation software, which used low-pass filtering and a forward prediction algorithm to calculate an offset. The offset was then used by the graphics software to display the correct image to the driver.

    The effects of driving with motion parallax in the simulator were also observed by an initial study. During the experiment, the subjects caught up with several slower vehicles which forced the driver to make an overtaking maneuver. Oncoming traffic forced the subject to search for a suitable gap for overtaking. The study also included a speed perception test. The results from the study showed no difference in lateral positioning when running behind a slower vehicle nor in speed perception with and without motion parallax.

  • 49.
    Andersson, Jan
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Eriksson, Gabriella
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Abadir Guirgis, Georg
    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.
    Ihlström, Jonas
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Sommarström, Erik
    Swedish National Road and Transport Research Institute.
    Thorslund, Birgitta
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Läsbarhet av vägskyltar i form av LED-skylt: färgkombination och fontstorlekens betydelse för läsbarheten2015Report (Other academic)
    Abstract [en]

    The readability of road signs was studied and in particular the LED format. The purpose of this study was to study the effect of color combination, font size and light conditions on readability. 101 students participated in the study, where 32 were men and 69 were women. Their age ranged from 18–66 years. The choice of subjects were driven by the study's purpose, i.e. for this study it was not of interest to study the differences between gender, age or eyesight. A statistical analysis was carried out to study how readability distances varied as a result of the combination of colors, font size and light conditions. Furthermore, illuminance was measured when the data collection occasions was conducted. Distances were examined both in daylight and in darkness. The results of the study show that the color combination of the LED-sign affects its readability. Signs with white text on blue, brown or green background could be read correctly at a greater distance than the signs with black text on white or orange background. The font size is also important for the readability and every increase in font size produces a significant difference in the distance that the sign can be read. The sign with the largest font size (300 mm) was read correctly from the longest distance. The signs were read even at greater distances in daylight than in darkness. The readability of the sign with the smallest font size 200 mm does not change significantly during the daylight compared to darkness conditions. These conclusive results demonstrate that all the variables studied are important for readability. It should be added that participants stood still during the trial when they scanned/read the signs and had free sight to the LED-sign.

  • 50.
    Andersson, Jan
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users.
    Peters, Björn
    Swedish National Road and Transport Research Institute, Traffic and road users, Körsimulering och visualisering, SIM.
    Simulatorbaserad testmetod: bedömning av körförmåga hos individer med synfältsbortfall2016Report (Other academic)
    Abstract [en]

    This project is a method project in its proper sense. The aim of the project was to develop a method to assess if individuals with visual field loss can drive in a safe manner. The starting point for the project was that the method should be a simulator based method because essentially two criteria were desirable. First, it was important that several events occurred systematically and that events were possible to evaluate, i.e., that it was possible to discriminate between good and bad performances. Second, these events should be the same events for all individuals that was to be tested. The aim was to develop a method that optimizes the validity and reliability with respect to testing of each and one of unique individuals. The testing procedure of the individual level was important because the method would not be used for research purposes but primarily to determine whether a unique individual with visual field loss can drive in a safe manner. Several details that can go wrong during an ordinary experiment, when running subjects, have a minimal impact concerning the experiment because it is most often possible to complement the experimental data collection with another subject. This is not an option for this project.

    These criteria and points raised above collectively resulted in the method developed. When an individual completed the scenario developed, a test protocol was generated (after a lot of work). This protocol reveals how the individual performed during the 37 (+2) events (and related measures) based on a safety margin perspective. To support the rater with the assessment of a subject a) data from a reference group (over 100 individuals) and b) a developed test protocol (with critical thresholds for different measurements) were used. The assessment was carried out by two independent raters. If the raters agreed no further judgments were performed. If the raters disagreed a third rater assessed the subjects’ performance. The purpose of the test protocol is that those individuals who want to use the test protocol results as a basis for an exemption application, can do so. It is still the Transport Agency, which decides on an exemption cases.

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