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  • 1.
    Abtahi, Farhad
    et al.
    Kungliga Tekniska Högskolan.
    Anund, Anna (red.)
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL.
    Fors, Carina
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL.
    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, 149-152 p.Conference 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.

  • 2.
    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, 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.

  • 3.
    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.

  • 4.
    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, 22-30 p.Article 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.

  • 5.
    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, 20-32 p.Article 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.

  • 6.
    Andersson, Jan
    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.
    Renner, Linda
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Andersson Hultgren, Jonas
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Hjort, Mattias
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Sandin, Jesper
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Almqvist, Sverker
    Swedish National Road and Transport Research Institute.
    Trafiksäkerhetspåverkan vid omkörning av 30-metersfordon2011Report (Other academic)
    Abstract [en]

    The Swedish Road Administration considers permitting longer and heavier trucks on Swedish roads, provided that they do not affect traffic safety. The purpose of the study was to investigate the effect of truck length, particularly accident risk associated with overtaking. Interviewed drivers of 30 meter trucks had not experienced the problems predicted by drivers of ordinary trucks concerning narrow roundabouts and intersections, but mentioned the importance of a supportive truck company, working environment and truck equipment. A simulator study investigated car drivers overtaking trucks 30 m and 18.75 m long on a 2+1 road where two lanes merges to one. The headway time gap was 0.2 sec. (sign.) shorter after overtaking the 30 meter truck in situations where the back was in the same relative position as of the 18.75 meter truck. A field study analysed video-recorded overtakings of a 30 meter and a 24 meter timber truck on a 2+1 road and a two-lane road. No significant differences were found between headway time gaps when overtaking the two trucks, regardless of road type. The latter result should be interpreted with great caution because of unevenly distributed data collected during specific conditions. The conclusions are that longer trucks may have a small negative effect on overtaking situations, and that further field studies are required.

  • 7.
    Andersson, Jan
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Sandin, Jesper
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Renner, Linda
    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.
    Strand, Niklas
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Hjort, Mattias
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Hultgren, J
    Almqvist, S
    Traffic safety effects when overtaking 30 meter trucks2012In: Advances in Human Factors and Ergonomics 2012- 14 Volume Set: Proceedings of the 4th AHFE Conference 21-25 July 2012 / [ed] Gavriel Salvendy, Waldemar Karwowski, Taylor & Francis, 2012Conference paper (Refereed)
    Abstract [en]

    The purpose of this paper is to investigate if the introduction of extra-long and heavy trucks has an effect on traffic safety on Swedish roads, especially in relation to overtaking maneuvers. Traffic safety effects will be measured in terms of road user behavior concerning accelerations and time slots. First, focus group interviews with heavy truck drivers. Truck drivers that do not drive extra-long trucks believe that the introduction of extra-long trucks will create a number of traffic safety problems especially in terms of conflicts with ordinary road users. The drivers of extra-long trucks do not experience the problems that ordinary truck drivers predict. The problems they experience can be taken care of with more planning (thinking ahead). They also believe that the traffic sign on the back of the extra-long vehicle has a positive effect. The truck company, working environment and truck equipment are other important aspects mentioned by the drivers of the extra-long vehicles.

    The simulator study investigates overtaking situations on a 2+1-lane highway, with extra-long trucks (30.4 m) and ordinary trucks (18.75 m). The results reveal that the distance from the rear/front of the truck to the point where only one lane exists affects car drivers’ decision to overtake, independently of truck length. If the truck is in the relatively same position, the timeslot for a safe overtaking maneuver before next one-lane section was reduced significantly for extra-long trucks compared to ordinary trucks. The conclusion is that there exist small tendencies which point in the direction of enhanced traffic safety problems with the introduction of extra-long trucks. The results should, however, be interpreted with caution as the number of data points was few and collected in specific situations and in specific conditions. It was neither considered how the introduction of longer and heavier trucks, given a constant amount of goods, reduces the number of heavy trucks on the road network.

  • 8.
    Anund, Anna
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL. Linköpings Universitet.
    Fors, Carina
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL.
    Ahlström, Christer
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL.
    The severity of driver fatigue in terms of line crossing: a pilot study comparing day- and night time driving in simulator2017In: European Transport Research Review, ISSN 1867-0717, E-ISSN 1866-8887, Vol. 9, no 2, 31Article in journal (Refereed)
    Abstract [en]

    Introduction: The overall aim of this study is to compare day-time driving with night-time driving looking at line crossings during self-reported sleepiness and long blinks. The hypothesis is that high levels of self-reported sleepiness (KSS 9) and long blink duration (>0.15 s) will be less associated with critical events during the day-time compared to night-time.

    Method: The study is based on data from a driving simulator experiment with 16 participants driving 150 km on a typical Swedish motorway scenario twice: once during daytime and once during night time. In total data from 6 segments of 4 km each equally distributed along the drive was averaged and included in the analysis. A Mixed Model Anova was used to test the effects on KSS, Blink Duration and Line Crossings with factors for Session (Day/Night) and Road segment (1–6), and participant as random. In addition, a logistic regression was used to identify when there is a risk for line crossings. Finally, the proportion of line crossings in relation to high KSS values and long blink durations was tested with Fisher’s exact test.

    Results: The results show no differences in the percentage of Line Crossings to the left during high levels of Karolinska Sleepiness Scale during daytime (33%) compare to night-time (40%). However, there was a significant difference between day and night time line crossings while the driver had long duration blinks (4% during daytime and 35% during night-time). Despite these results the most promising predictor of line crossings in each segment of 4 km/h was KSS with an Odds Ratio of 5.4 with a reference value at Karolinska Sleepiness Scale level 5.

    Conclusion: In conclusion, the results do not support the hypothesis that high levels of KSS will result in more frequent line crossings at night time compared to day time. However, the result supports the hypothesis that long blink durations are associated with more line crossings when they appear during night time than during daytime. © 2017, The Author(s).

  • 9.
    Anund, Anna
    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.
    Eriksson, Jennie
    Occas AB.
    Utvärderingsmodell för ITS-baserade system vid hållplats: kunskapsöversikt och förslag på forskningsbehov2015Report (Other academic)
    Abstract [sv]

    Det finns nya produkter av typen varningssystem som syftar till att öka säkerhet och trygghet för oskyddade trafikanter. De har ofta tagits fram med särskilt fokus på barn. Produktutvecklarna har utvärderat sina produkter med positiva resultat och intresset hos Trafikverket och kommuner är stort för flera av dessa produkter. En typ av system är utmärkning vid hållplatser där blinkande ljus aktiveras när det finns oskyddade trafikanter i närheten, ett så kallat ITS-baserat varningssystem. Det finns idag ett antal platser i landet där sådana anläggningar är i bruk som ”försök” och det har skett utvärderingar av valda system vid hållplats som visat att systemen sannolikt är effektiva när det gäller att reducera hastigheten hos förbipasserande. Det finns dock en avsaknad av ett samlat utvärderingsupplägg. Avsaknaden av systematisk utvärdering har bidragit till bristen på formella beslut för att integrera denna typ av produkt i Vägar och Gators Utformning, VGU eller i Trafiklagstiftningen. I Trafikverkets region Stockholm har man utifrån resenärernas behov och i samarbete med kommunerna kring glesbygdsproblematik, särskilt intresse i att dessa produkter blir möjliga att använda. En förutsättning för detta är en systematisk utvärdering med avseende på om ett specifikt system fyller den funktion som det var avsett att fylla.

  • 10.
    Anund, Anna
    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.
    Hallvig, David
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Åkerstedt, Torbjörn
    Stress Research Institute, Stockholm.
    Kecklund, Göran
    Stress Research Institute, Stockholm.
    Observer Rated Sleepiness and Real Road Driving: An Explorative Study2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 5, e64782- p.Article in journal (Refereed)
    Abstract [en]

    The aim of the present study was to explore if observer rated sleepiness (ORS) is a feasible method for quantification of driver sleepiness in field studies. Two measures of ORS were used:

    1. one for behavioural signs based on facial expression, body gestures and body movements labelled B-ORS, and
    2. one based on driving performance e.g. if swerving and other indicators of impaired driving occurs, labelled D-ORS

    A limited number of observers sitting in the back of an experimental vehicle on a motorway about 2 hours repeatedly 3 times per day (before lunch, after lunch, at night) observed 24 participant's sleepiness level with help of the two observer scales. At the same time the participant reported subjective sleepiness (KSS), EOG was recorded (for calculation of blink duration) and several driving measure were taken and synchronized with the reporting.

    Based on mixed model Anova and correlation analysis the result showed that observer ratings of sleepiness based on drivers' impaired performance and behavioural signs are sensitive to extend the general pattern of time awake, circadian phase and time of driving. The detailed analysis of the subjective sleepiness and ORS showed weak correspondence on an individual level. Only 16% of the changes in KSS were predicted by the observer. The correlation between the observer ratings based on performance (D-ORS) and behavioural signs (B-ORS) are high (r =. 588), and the B-ORS shows a moderately strong association (r =. 360) with blink duration. Both ORS measures show an association (r>0.45) with KSS, whereas the association with driving performance is weak.

    The results show that the ORS-method detects the expected general variations in sleepy driving in field studies, however, sudden changes in driver sleepiness on a detailed level as 5 minutes is usually not detected; this holds true both when taking into account driving behaviour or driver behavioural signs.

  • 11.
    Anund, Anna
    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, Trafikanttillstånd, TIL.
    Ihlström, Jonas
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Bus drivers working hours and the relationship to driver fatigue2016Conference paper (Refereed)
    Abstract [en]

    Bus drivers often have irregular working hours like split shifts and their work involve high levels of stress. These factors can lead to severe sleepiness and dangerous driving. The purpose of this study is to highlight how split shifts affect sleepiness and performance during afternoon drive. The study is an experiment on real road with an equipped bus driven by professional bus drivers. The study design is a within subject design and the 18 professional bus drivers (9 males and 9 females) drove twice during afternoon; once after a day with bus driving in the morning and once after a day when they had been off duty the whole day. The hypotheses was that split shifts contribute to sleepiness during afternoon, which together can result in increased safety risks. The overall results support this hypotheses. In total five out of 18 drivers reached levels of severe sleepiness (Karolinska Sleepiness Scale ≥ 8) with an average increase in KSS of 1,94 driving in the afternoon the day that preceded with bus driving in the morning compared to the day off duty in the morning, an increase corresponding to the levels of shift workers comparing start and end of a night shift. The Psychomotor Vigilance Task showed significant increased Response Time with split shift (afternoon: 0.337s; split shift 0.347s), so did also the EEG based KDS mean/max. Blink duration also increased, even though the difference was not significant. One driver fell asleep during the drive. In addition, 12 of the 18 bus drivers reported that they in their daily work had to fight to stay awake while driving the bus at least 2-4 times per month.  Even though the study showed significant induvial differences, it is clear that the bus drivers had to fight to stay awake and countermeasures are needed in order to guarantee safe driving under split shift schedules.

  • 12.
    Anund, Anna
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL.
    Fors, Carina
    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.
    Kecklund, Göran
    Stockholms Universitet.
    An on-road study of sleepiness in split shifts among city bus drivers2016In: Accident Analysis and Prevention, ISSN 0001-4575, E-ISSN 1879-2057Article in journal (Refereed)
    Abstract [en]

    Bus drivers often work irregular hours or split shifts and their work involves high levels of stress. These factors can lead to severe sleepiness and dangerous driving. This study examined how split shift working affects sleepiness and performance during afternoon driving. An experiment was conducted on a real road with a specially equipped regular bus driven by professional bus drivers.

    The study had a within-subject design and involved 18 professional bus drivers (9 males and 9 females) who drove on two afternoons; one on a day in which they had driven early in the morning (split shift situation) and one on a day when they had been off duty until the test (afternoon shift situation). The hypothesis tested was that split shifts contribute to sleepiness during afternoon, which can increase the safety risks. The overall results supported this hypothesis. In total, five of the 18 drivers reached levels of severe sleepiness (Karolinska Sleepiness Scale ≥8) with an average increase in KSS of 1.94 when driving in the afternoon after working a morning shift compared with being off duty in the morning. This increase corresponded to differences observed between shift workers starting and ending a night shift. The Psychomotor Vigilance Task showed significantly increased response time with split shift working (afternoon: 0.337. s; split shift 0.347. s), as did the EEG-based Karolinska Drowsiness Score mean/max. Blink duration also increased, although the difference was not significant. One driver fell asleep during the drive. In addition, 12 of the 18 bus drivers reported that in their daily work they have to fight to stay awake while driving at least 2-4 times per month. While there were strong individual differences, the study clearly showed that shift-working bus drivers struggle to stay awake and thus countermeasures are needed in order to guarantee safe driving with split shift schedules.

  • 13.
    Anund, Anna
    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.
    Kecklund, Göran
    Stockholm University.
    Leeuwen, Wessel van
    Stockholm University.
    Åkerstedt, Torbjörn
    Stockholm University.
    Countermeasures for fatigue in transportation: a review of existing methods for drivers on road, rail, sea and in aviation2015Report (Other academic)
    Abstract [en]

    The overall aim with this study was to gather knowledge about countermeasures for driver fatigue (including sleepiness) in road, rail, sea and air transportation. The knowledge has been used as an input for evaluating advantages and disadvantages with different countermeasures and to estimate their potential to be used regardless mode of transportation. The method used was a literature review and a workshop with experts from all transportation modes. At the workshop the effectiveness of countermeasures for a single mode, but also regardless mode were discussed and a ranking was done. The report discuss the potential of fighting fatigue among drivers for specific mode of transport but also from a more generic point of view, considering scheduling, model prediction of fatigue risk, legislation, a just culture, technical solutions, infrastructure, education, self-administered alertness interventions and fatigue risk management (FRM). The overall judgement was that a just culture, education, possibility to nap and schedules taking the humans limitations into consideration as the most effective countermeasures to fight fatigue, regardless mode of transportation.

  • 14.
    Anund, Anna
    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, Human-vehicle-transport system interaction.
    Fors, Carina
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL.
    Kecklund, Göran
    Stockholms Universitet.
    Filtness, Ashleigh
    Queensland University of Technology (QUT).
    Factors associated with self-reported driver sleepiness and incidents in city bus drivers2016In: Industrial Health, ISSN 0019-8366, E-ISSN 1880-8026, Vol. 54, no 4, 337-346 p.Article in journal (Refereed)
    Abstract [en]

    Driver fatigue has received increased attention during recent years and is now considered to be a major contributor to approximately 15-30% of all crashes. However, little is known about fatigue in city bus drivers. It is hypothesized that city bus drivers suffer from sleepiness, which is due to a combination of working conditions, lack of health and reduced sleep quantity and quality.

    The overall aim with the current study is to investigate if severe driver sleepiness, as indicated by subjective reports of having to fight sleep while driving, is a problem for city based bus drivers in Sweden and if so, to identify the determinants related to working conditions, health and sleep which contribute towards this. The results indicate that driver sleepiness is a problem for city bus drivers, with 19% having to fight to stay awake while driving the bus 2-3 times each week or more and nearly half experiencing this at least 2-4 times per month. In conclusion, severe sleepiness, as indicated by having to fight sleep during driving, was common among the city bus drivers. Severe sleepiness correlated with fatigue related safety risks, such as near crashes.

  • 15.
    Anund, Anna
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kecklund, Göran
    Stockholms universitet, Karolinska Institutet.
    Fors, Carina
    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.
    Ingre, Michael
    Stockholms universitet.
    Radun, Igor
    University of Helsinki.
    Söderström, Beatrice
    Swedish National Road and Transport Research Institute, Infrastructure, Crash safety.
    Bussförares arbetstider kopplat till trötthet2014Report (Other academic)
    Abstract [en]

    Bus drivers often have irregular working hours and their work involve high levels of stress. These factors can lead to severe fatigue and the purpose of this study is to highlight how the working hours affect sleep, stress, fatigue and driving performance. The project includes four studies: questionnaire, sleep diaries and actigraphy, analyze of rosters and an experiment on real road with bus drivers. The hypotheses were that early morning shift, split shifts, long working hours and short hours of rest between shifts contribute to sleepiness, stress, fatigue and impaired driving performance, which together can result in increased safety. The overall results support these hypotheses. Generally, sleepiness and fatigue while driving are perceived as problems because drivers connect those factors with impaired driving performance, which increases the risk of incidents and accidents. In total 45 percent of all drivers had trouble at least twice a month to stay awake while driving and 19 percent had over the past decade been involved in an incident due fatigue. The experiment with split shift driving support these findings. The report concludes with a list of suggestions.

  • 16.
    Anund, Anna
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Lahti, Eva
    Volvo Car Cooperation.
    Fors, Carina
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Genell, Anders
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    The effect of low-frequency road noise on driver sleepiness and performance2015In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 4, e0123835Article in journal (Refereed)
    Abstract [en]

    The aim of this moving base driving simulator study with 19 drivers participating in a random order day and night time, was to evaluate the effect of low-frequency road noise on driver sleepiness and performance, including both long-term and short-term effects.

    It is a well-known fact today that driver sleepiness is a contributory factor in crashes. Factors considered as sleepiness contributor are mostly related to time of the day, hours being awake and hours slept. Factors contributing to active and passive fatigue are mostly focusing on the level of cognitive load. Less is known what role external factors, e.g. type of road, sound/noise, vibrations etc., have on the ability to stay awake both under conditions of sleepiness and under active or passive fatigue.

    The results support to some extent the hypothesis that road-induced interior vehicle sound affects driving performance and driver sleepiness. Increased low-frequency noise helps to reduce speed during both day- and night time driving, but also contributes to increase the number of lane crossings during night time.

  • 17.
    Filtness, Ashleigh J
    et al.
    Queensland University of Technology.
    Anund, Anna
    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.
    Ahlström, Christer
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Åkerstedt, Torbjörn
    Stockholms Universitet.
    Kecklund, Göran
    Stockholms Universitet.
    Sleep-related eye symptoms and their potential for identifying driver sleepiness2014In: Journal of Sleep Research, ISSN 0962-1105, E-ISSN 1365-2869, Vol. 23, no 5, 568-75 p.Article in journal (Refereed)
    Abstract [en]

    The majority of individuals appear to have insight into their own sleepiness, but there is some evidence that this does not hold true for all, for example treated patients with obstructive sleep apnea. Identification of sleep-related symptoms may help drivers determine their sleepiness, eye symptoms in particular show promise. Sixteen participants completed four motorway drives on two separate occasions. Drives were completed during daytime and night-time in both a driving simulator and on the real road.

    Ten eye symptoms were rated at the end of each drive, and compared with driving performance and subjective and objective sleep metrics recorded during driving. 'Eye strain', 'difficulty focusing', 'heavy eyelids' and 'difficulty keeping the eyes open' were identified as the four key sleep-related eye symptoms. Drives resulting in these eye symptoms were more likely to have high subjective sleepiness and more line crossings than drives where similar eye discomfort was not reported. Furthermore, drivers having unintentional line crossings were likely to have 'heavy eyelids' and 'difficulty keeping the eyes open'. Results suggest that drivers struggling to identify sleepiness could be assisted with the advice 'stop driving if you feel sleepy and/or have heavy eyelids or difficulty keeping your eyes open'.

  • 18.
    Fors, Carina
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Samband mellan synbarhet och vägbelysningens färg: en litteraturstudie om mätmetoder och synbarhetsexperiment2010Report (Other academic)
    Abstract [en]

    Available methods for measuring and describing street lighting parameters are based on how the human eye perceives light in daylight conditions. In night-time traffic where the light levels are low - in the so called mesopic range - the current methods can be misleading. Better measurement methods can give better and more uniform light conditions, but also energy savings. This report summarizes literature on new mesopic measurement methods and models that better than today's methods predict visual performance in different types of street lighting at low light levels. Furthermore, studies on the relationship between visual performance and the colour spectrum of the light are reviewed.

  • 19.
    Fors, Carina
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL.
    Ahlström, Christer
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL.
    Anund, Anna
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL.
    A comparison of driver sleepiness in the simulator and on the real road2016In: Journal of Transportation Safety and Security, ISSN 1943-9962, 1-16 p.Article in journal (Refereed)
    Abstract [en]

    For safety reasons as well as for experimental control, driver sleepiness experiments are often run in simulators. The aim of this study is to compare the development of driver sleepiness in an advanced driving simulator experiment with real road driving. Sixteen drivers participated in the experiment, which included daytime and night-time driving on a real motorway and in an advanced driving simulator.

    The results showed that there were significantly higher levels of Karolinska Sleepiness Scale (KSS) ratings, longer blink durations, lower percentage of gazes directed toward the road center (PRC), and higher speed, in the simulator compared to the real road. The pattern of change with task progression was consistent between simulator driving and real road driving for all investigated variables, that is, speed, KSS, line crossings, blink duration, and PRC. However, the relative differences were higher during daytime compared to night-time driving.

    Results from a questionnaire showed that it was more boring and more demanding to stay alert in the simulator. In conclusion, the development of sleepiness over time is similar in the simulator as compared to the real road, though the absolute sleepiness level is higher in the simulator.

  • 20.
    Fors, Carina
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Ahlström, Christer
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Anund, Anna
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Simulator validation with respect to driver sleepiness and subjective experiences: final report of the project SleepEYE II, part 12013Report (Other academic)
    Abstract [en]

    In the previous project SleepEYE, which aimed at developing tools for driver sleepiness detection, two experiments were carried out. In the first experiment, 18 drivers conducted two driving sessions on a motorway: one during daytime (alert) and one at night (sleep deprived). Sixteen of the drivers participated in the second experiment, which was similar to the first one, except that the driving sessions were conducted in an advanced moving base driving simulator. In the present study, the validity of the simulator was assessed using data that was collected in the two experiments. The validation analysis had three focuses: 1) general driver and driving behaviour related to driver sleepiness, 2) speed profile at change in posted speed limit, and 3) drivers’ subjective experience of the vehicle, the driving environment and the own driving performance. The results showed that there were significant differences in mean speed, blink duration, percentage road centre (gaze), radius of 95 per cent cone (gaze) and KSS between the simulator and the real road. No such differences were found for left and right line crossings. For all indicators except blink duration, there was no interaction effect between platform (simulator vs. real road) and time on task, which indicates that the signs of sleepiness vary in a similar way regardless of platform. In conclusion, differences between the simulator and the real road with respect to driving and driver behaviour as well as subjective experiences were found, mainly in terms of speed, level of sleepiness and subjective experience of the vehicle. However, the signs of sleepiness and the development of sleepiness over time are similar in the simulator and on the real road, although the level is higher in the simulator. Thus, there is a relative but not absolute validity with respect to driver sleepiness. Similarly, there seems to be a relative validity for speed and changes in speed.

  • 21.
    Fors, Carina
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Ahlström, Christer
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Sörner, Per
    Smart eye.
    Kovaceva, Jordanka
    Volvo cars.
    Hasselberg, Emanuel
    Smart eye.
    Krantz, Martin
    Smart eye.
    Grönvall, John-Fredrik
    Volvo cars.
    Kircher, Katja
    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.
    Camera-based sleepiness detection: final report of the project SleepEYE2011Report (Other academic)
    Abstract [en]

    Two literature reviews were conducted in order to identify indicators of driver sleepiness and distraction. Three sleepiness indicators – blink duration, blink frequency and Perclos – were implemented in the camera system.

    The aims of the study were firstly to develop and evaluate a low cost 1-camera unit for detection of driver impairment, and secondly to identify indicators of driver sleepiness and to create a sleepiness classifier for driving simulators.

    The project included two experiments. The first was a field test where 18 participants conducted one alert and one sleepy driving session on a motorway. 16 of the 18 participants also participated in the second experiment which was a simulator study similar to the field test.

    The field test data was used for evaluation of the 1-camera system, with respect to the sleepiness indicators. Blink parameters from the 1-camera system was compared to blink parameters obtained from a reference 3-camera system and from the EOG. It was found that the 1-camera system missed many blinks and that the blink duration was not in agreement with the blink duration obtained from the EOG and from the reference 3-camera system. However, the results also indicated that it should be possible to improve the blink detection algorithm since the raw data looked well in many cases where the algorithm failed to identify blinks.

    The sleepiness classifier was created using data from the simulator experiment. In the first step, the indicators identified in the literature review were implemented and evaluated. The indicators also included driving and context related parameters in addition to the blink related ones. The most promising indicators were then used as inputs to the classifier.

  • 22.
    Fors, Carina
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Carlson, Annelie
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Revision of criteria for selection of road lighting class: a pre-study2015Report (Other academic)
    Abstract [en]

    The aim of this project is to investigate the potential in decreasing the energy use of road lighting by a revision of the guidelines regarding the selection of lighting level. The starting point of this work has been the method for selection of lighting classes suggested in the recently published technical report CEN/TR 13201-1, which considers road lighting for drivers and for vulnerable road users. In order to investigate whether CEN/TR 13201-1 is applicable in Sweden, a literature review on guidelines and criteria for selection of road lighting classes was carried out, with the aim of identifying criteria that are scientifically grounded. The literature review was supplemented by a workshop where road lighting criteria were discussed by invited road lighting experts from the Nordic countries. The results from the study show that there is some support that the parameters traffic volume, traffic composition, separation of carriageways, ambient luminosity and navigational task are relevant for the selection of road lighting class, but also that there is a lack of knowledge of road users’ needs and experiences of road lighting. The report gives recommendations for further work on a revision of the guidelines for road lighting, and suggestions for further research studies.

  • 23.
    Fors, Carina
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Hallvig, David
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Hasselberg, Emanuel
    Smart Eye.
    Kovaceva, Jordanka
    Volvo Cars.
    Sörner, Per
    Smart Eye.
    Krantz, Martin
    Smart Eye.
    Grönvall, John-Fredrik
    Volvo Cars.
    Anund, Anna
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Investigation of driver sleepiness in FOT data: final report of the project SleepEYE II, part 22013Report (Other academic)
    Abstract [en]

    Driver sleepiness contributes to a great number of motor vehicle accidents every year. In order to reduce the number of sleepiness related accidents, more knowledge on e.g. prevalence, countermeasures and driver behaviour is needed. Data from field operational tests (FOT) has a potential to provide such knowledge with high ecological validity. The objective of the project was to propose and evaluate methods for identification of driver sleepiness in FOT data. More specifically, the aim was to identify objective indicators of sleepiness – based on driving behaviour, eye blink behaviour and models of circadian rhythm – and to evaluate a subjective video scoring method for estimating driver sleepiness levels. Data from two separate projects were used: 1) the ViP-project SleepEYE, in which a controlled field test was conducted, and 2) euroFOT, which was a large scale FOT. In a first step the data quality of blink-based indicators obtained from a camera system was evaluated. It was concluded that the data quality had to be improved and thus, a new detection algorithm was devised and implemented. The new detection algorithm had an acceptable detection rate (approximately 50 %) when applied to data from the SleepEYE field test, but for euroFOT data the number of identified blinks was very low (< 5 blinks/min) in about half of the trips. There is thus a need for further improvements of the blink detection algorithm. An in-depth study on indicators of driver sleepiness was carried out using data collected in the SleepEYE experiment, with the purpose of employing the best indicators to study driver sleepiness in the euroFOT database. The most promising indicators were found to be mean blink duration and number of line crossings. A sleepiness classifier was suggested based on the distribution of the data (i.e. visual inspection). When applied to SleepEYE data the classifier was found to have good specificity while the sensitivity of the classifier was not so good. From euroFOT no true data on the drivers’ sleepiness levels were available and it was therefore not possible to evaluate the performance of the classifier. However, an explorative analysis showed that only very few data points were classified as sleepy. This may be reasonable since most trips were conducted during daytime, but it is a somewhat disappointing result for the project. A study was carried out on whether it is possible to use video recordings of drivers in order to estimate the drivers’ self-rated level of sleepiness. Forty participants rated 54 one-minute video clips of an equal number of sleepy and alert drivers on a scale with three levels (alert, first signs of sleepiness, very sleepy). The results of the study showed that performing such observer rated sleepiness (ORS) estimations on drivers is extremely difficult. The videos available in FOTs are usually of rather poor quality which, clearly limits the possibility of making reliable observer rated sleepiness estimations. In conclusion, studying driver sleepiness in (existing) FOT data is difficult, for several reasons: 1) eye camera based indicators suffer from detection errors and low detection rate, 2) driving-based indicators are influenced by e.g. road curvature and traffic density, 3) models of sleepiness cannot be used since no information on hours slept and time awake is available, and 4) video scoring is not reliable, at least not given the quality of the available video recordings. In future studies on driver sleepiness in FOTs sleepiness should be addressed in the FOT design. Some information about the drivers' sleep and sleepiness (ratings, sleep diaries, etc.) must be collected during the test; otherwise it will be very difficult to get any useful results.

  • 24.
    Fors, Carina
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Hjälmdahl, Magnus
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Hjorth, Lars
    Scania.
    Accelerated testing of FCW for trucks: part 2: driving behaviour after exposure to repeated critical events2010Report (Other academic)
    Abstract [en]

    Forward collision warning (FCW) systems alert the driver of an imminent rear-end collision with the vehicle ahead. FCW systems are difficult to test and evaluate in a real driving situation and a simulator study can thus be a feasible way of assessing various aspects of FCW systems, such as effectiveness and acceptance. A driving simulator allows for repeated exposure to critical situations, however, there is a risk that repeated critical situations reduce the realism and result in a change in driving behaviour. The aim of this study was to assess driving behaviour during non-critical parts of a driving session that contained repeated critical situations. In a truck simulator 48 professional drivers participated in two driving sessions. The first session aimed at evaluating a FCW system which is reported elsewhere (classified). The second session was a 35 min long motorway drive with two critical and three less critical events. Between all events there was a car following situation. 32 of the drivers had a FCW system while the remaining 16 drivers had no FCW. Mean speed between the events, minimum distance to the vehicle in front in the car following situation, and performance on a secondary task - the arrows task - were used as measures of driving behaviour. In addition, the drivers answered a questionnaire about their driving behaviour.

  • 25.
    Fors, Carina
    et al.
    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.
    Nygårdhs, Sara
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Symboler i vägbanan: en sammanställning av gällande regelverk i Danmark, Finland, Norge, Sverige, Nederländerna, Storbritannien och Tyskland2012Report (Other academic)
    Abstract [en]

    The aim of this study has been to synthesize existing regulations and guiding principles for use of road marking symbols in the Nordic countries Denmark, Finland, Norway and Sweden, together with the Netherlands, Great Britain and Germany. Additionally, a small literature study has been carried out in order to investigate what documented knowledge the regulations are based upon. Road marking symbols are used in a similar way in the studied countries. However, documented knowledge and research on what the symbols should look like are to a great extent missing. Therefore, it should be possible to standardize the road marking symbols within the Nordic countries, which could lead to a more homogeneous impression where the road users recognize and understand the information, at the same time as the application of the symbols could be simplified.

    In summary, the following road marking symbols could be of interest to standardize within the Nordic countries, regarding use, design and dimensions:

    • Lane arrows
    • Deflection arrows
    • Give way symbols
    • STOP text
    • Speed limit symbols
    • Road numbers
  • 26.
    Fors, Carina
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Johansen, Trond Cato
    Ramböll.
    Lundkvist, Sven-Olof
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Nordic certification system for road marking materials: version 1:20152015Report (Other academic)
    Abstract [en]

    A Nordic certification system for road marking materials will be introduced in 2015. The system will be based on documented performance measurements of material samples applied on test fields on public roads. This report describes the certification system and how it will be applied in the Nordic countries. Procedures and methods that will be used for application of materials and performance measurements are specified.

  • 27.
    Fors, Carina
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Johansen, Trond Cato
    Ramböll Sverige AB.
    Lundkvist, Sven-Olof
    Nordic certification system for road marking materials: version 2:20152015Report (Other academic)
    Abstract [en]

    A Nordic certification system for road marking materials was introduced in 2015. The system is based on documented performance measurements of material samples applied on test fields on public roads. The report describes the certification system and how it will be applied in the Nordic countries. Procedures and methods used for application of materials and performance measurements are specified.

  • 28.
    Fors, Carina
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL.
    Johansen, Trond Cato
    Ramböll.
    Lundkvist, Sven-Olof
    Nordic certification system for road marking materials: version 3:20162016Report (Other academic)
    Abstract [en]

    The report describes the certification system for road marking materials and how it is applied in the Nordic countries. Procedures and methods that are used for application of materials and performance measurements are specified. The Nordic certification system for road marking materials was introduced in 2015. The system is based on documented performance measurements of material samples applied on test fields on public roads. From 2016, the certification system includes both flat (type I) and structured/profiled (type II) markings. The certification system is based on the European standards EN 1824 Road marking materials – Road trials, EN 1436 Road marking materials – Road marking performance for road users, and EN 12802 Road marking materials – Laboratory methods for identification. Material tests are carried out at two test sites: one in Sweden and one in Denmark. The tests fields are situated on public roads and the tested materials are thus exposed to real traffic conditions and to weather conditions representative for the Nordic countries. The materials are followed up by performance measurements during one or two years. The certification includes requirements on coefficient of retroreflected luminance RL under dry and wet conditions, luminance coefficient under diffuse illumination Qd, friction and colour coordinates. The number of wheel passages are measured at the test sites annually. The certification system includes material identification, which allows for future material sampling and analysis.

  • 29.
    Fors, Carina
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL.
    Johansen, Trond Cato
    Ramböll.
    Lundkvist, Sven-Olof
    Nygårdhs, Sara
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL.
    Nordic certification system for road marking materials: version 4:20172017Report (Other academic)
    Abstract [en]

    Nordic certification system for road marking materials was introduced in 2015. The system is based on documented performance measurements of material samples applied on test fields on public roads. From 2016, the certification system includes both flat (type I) and structured/profiled (type II) markings. Since 2017 the certification system also includes friction materials (a material with enhanced friction).

    Material tests are carried out at two test sites: one in Norway and one in Denmark. The tests fields are situated on public roads and the tested materials are thus exposed to real traffic conditions and to weather conditions representative for the Nordic countries. The materials are followed up by performance measurements during one or two years. The certification includes requirements on coefficient of retroreflected luminance RL under dry and wet conditions, luminance coefficient under diffuse illumination Qd, friction and colour coordinates. The number of wheel passages is measured at the test sites annually. The certification system includes material identification, which allows for future material sampling and analysis.

    The certification system is based on the European standards EN 1824 Road marking materials – Road trials, EN 1436 Road marking materials – Road marking performance for road users, and EN 12802 Road marking materials – Laboratory methods for identification.

    The report describes the certification system and how it is applied in the Nordic countries. Procedures and methods that are used for application of materials and performance measurements are specified.

  • 30.
    Fors, Carina
    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.
    Ahlström, Christer
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Interface design of eco-driving support systems: Truck drivers’ preferences and behavioural compliance2015In: Transportation Research Part C: Emerging Technologies, ISSN 0968-090X, E-ISSN 1879-2359, Vol. 58, 706-720 p.Article in journal (Refereed)
    Abstract [en]

    The aim of the study was to investigate the perceived usefulness of various types of in-vehicle feedback and advice on fuel efficient driving. Twenty-four professional truck drivers participated in a driving simulator study. Two eco-driving support systems were included in the experiment: one that provided continuous information and one that provided intermittent information. After the simulator session, the participants were interviewed about their experiences of the various constituents of the systems. In general, the participants had a positive attitude towards eco-driving support systems and behavioural data indicated that they tended to comply with the advice given. However, different drivers had very different preferences with respect to what type of information they found useful. The majority of the participants preferred simple and clear information. The eco-driving constituents that were rated as most useful were advice on gas pedal pressure, speed guidance, feedback on manoeuvres, fuel consumption information and simple statistics. It is concluded that customisable user interfaces are recommended for eco-driving support systems for trucks.

  • 31.
    Fors, Carina
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Lundkvist, Sven-Olof
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Heldragen kantlinje på tvåfältsväg: hastighet och synbarhet2014Report (Other academic)
    Abstract [en]

    The aim was to investigate whether travel speed on two lane roads is influenced by the type of edge line. Another aim was to investigate whether there is a difference in durability for different line types. The study was carried out on a rural road segment. In year one, the entire road segment had a continuous edge line. In year two and three, half the segment had a continuous edge line, while the other half had a broken edge line. Travel speed of free flow passenger cars was measured each year, both in daylight and at night. The function of the edge lines was measured in terms of retroreflection and luminance coefficient. The results showed that the type of edge line did not have an influence on travel speed, neither in daylight nor at night. The preview time was significantly higher for the continuous than for the broken edge line. No difference in durability between the two line types could be observed during the two years the study was carried out. From a traffic safety and comfort perspective, the results point toward the use of continuous edge lines on two lane roads, at least on hilly and curving roads.

  • 32.
    Fors, Carina
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL.
    Lundkvist, Sven-Olof
    Swedish National Road and Transport Research Institute.
    Mätning av friktion på vägmarkering: jämförelse av olika metoder samt utveckling av modell för mobil mätning2016Report (Other academic)
    Abstract [en]

    For road markings, there is a performance requirement regarding friction, which is given in units obtained with handheld instruments. Such instruments are not suitable for assessment of friction on longer stretches of road, since it would be too time consuming and expensive. In order to be able to monitor a large road network and to assess whether the performance requirements are fulfilled, mobile measurement methods are needed, i.e. methods based on instruments mounted on vehicles. Besides, the friction that occurs between the tyres of a vehicle and the road surface is speed dependent. Handheld instruments reflect the friction that occurs in low speeds, while from a traffic safety perspective, friction in higher speeds is most relevant.

    The present report describes the results from two studies about methods for mobile assessment or estimation of road marking friction. In the first study, three different mobile methods, Road Friction Tester (RFT), Traction Watcher One (TWO) and Road Marking Tester (RMT), were compared to the handheld method Portable Friction Tester (PFT). In the second study, a prediction model for friction in higher speeds was developed, based on measurements of the coefficient of retroreflected luminance and the texture of the road marking.

    The first study showed that the different methods give different results, which is expected since the physical quantity coefficient of friction does not have a unique definition but is dependent on the properties of the instrument. In lower speeds, there were significant relationships between PFT and RFT, and between PFT and TWO (correlation coefficient 0,89 and 0,86, respectively). The relationships between PFT and RMT were somewhat weaker, although significant (correlation coefficients 0,65–0,71). In higher speeds, there was a significant relationship between RFT and TWO (correlation coefficient 0,80). The relationships between RMT and RFT, and between RMT and TWO, were weaker but significant (correlation coefficients 0,86–0,89). TWO gave lower friction values than the other methods. Measurement speed had an influence on the results obtained with RFT and TWO.

    In the second study, TWO was used as a reference when developing a prediction model for friction in higher speeds. The results showed that friction to some extent can be predicted from the coefficient of retroreflected luminance and the texture of the marking, but that the relationship is not strong enough for the model to be applicable. A limitation of the study is that there is no standardized method for measurement of road marking friction in higher speeds available. The reference method used, TWO, is developed for friction assessment of road surfaces and not for road markings, which implies that the ability of the instrument to assess road marking friction is somewhat uncertain.

  • 33.
    Fors, Carina
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Lundkvist, Sven-Olof
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Night-time traffic in urban areas: a literature review on road user aspects2009Report (Other academic)
    Abstract [sv]

    The aim of this literature study is to review recent research on night-time traffic from a road user perspective. The report discusses road users' behaviour, needs and problems in relation to other road users as well as to traffic environment. The study includes 128 references from 1998-2008 and it mainly concerns urban areas. The report begins with a chapter about accident statistics, followed by a theoretical background that includes lighting terminology, Swedish regulations on road equipment, and the human eye and night vision. The main part of the report has its focus on five road user groups - drivers, pedestrians, bicyclists, older people and visually impaired people - and their needs, difficulties, performances and behaviour in night-time traffic. The literature gives relatively much information about drivers' situation in night-time traffic, but there is a lack of knowledge in some areas such as drivers' interaction with parts of the driving environment. Also, there is partly a lack of knowledge on pedestrians and older road users. Regarding bicyclists and visually impaired people, there is only very limited literature available.

  • 34.
    Fors, Carina
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL.
    Lundkvist, Sven-Olof
    Englundh, Stig
    Mobil mätning av vägbelysning2017Report (Other academic)
    Abstract [en]

    For most types of road equipment there are regulations that set the performance requirements. For example, a road marking must have a minimum retroreflectivity for it to have sufficient visibility. Regarding road lighting there are multiple performance requirements in the Swedish Transport Administration's requirements for road and street design (VGU), including requirements for allowed glare, demands on shielding, illuminance and road surface luminance. On most roads and streets, the luminance requirement is the most important parameter, not least because this is important for the possibility of detecting pedestrians.

    For a requirement in the regulations to be meaningful, it is important that it is possible to check if the requirements are met. However, luminance measurements are complicated and susceptible to interference from ambient light sources.

    The purpose of this study was to develop a prototype of an instrument which enables fast mobile measurements of road surface luminance without the risk of interference from other traffic.

    Completed tests with the instrument have shown that the measurement of road surface luminance on longer sections can be performed, without light interference from other traffic. The measurements are also relatively rapid and requires a minimum of manual data processing. The measurement system additionally has good accuracy which makes it suitable for condition assessment of road lighting.

  • 35.
    Fors, Carina
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Nygårdhs, Sara
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Trafikanters upplevda behov och problem i mörkertrafik i tätort: en fokusgruppsstudie med cyklister, äldre bilförare och äldre fotgängare2010Report (Other academic)
    Abstract [en]

    The aim of this study was to improve knowledge on road users' experiences, problems and needs in night-time traffic in urban areas. Based on a previous literature study, the following road user groups were selected for a focus group study: bicyclists, older drivers and older pedestrians. All three focus groups thought that the problems in night-time traffic in urban areas mainly are related to pedestrians and bicyclists. They seldom have proper lighting and/or retroreflective markings and are thus difficult to detect, not only for drivers but also for other pedestrians and bicyclists. Furthermore, traffic rules for pedestrians and bicyclists are experienced as unclear and inconsistent, which causes irritation and may increase the risk of accidents. Both the bicyclist group and the group with older pedestrians asked for better road markings that clearly show where to walk and where to cycle, since they themselves sometimes find it difficult to know where to walk/cycle and also because they think other pedestrians and bicyclists walk or cycle on the wrong part of the road.

  • 36.
    Fors, Carina
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL.
    Yahya, Mohammad-Reza
    Swedish National Road and Transport Research Institute, Infrastructure, Measurement technology and engineering workshop.
    Lundkvist, Sven-Olof
    Intermittenta, heldragna och profilerade vägmarkeringars funktion över tid2016Report (Other academic)
    Abstract [en]

    Paved public roads usually have longitudinal road markings, which can be of different types. Two-lane roads should have a 10 or 15 cm wide broken edge line, but a continuous edge line can be used in order to enhance visibility. If the annual average daily traffic (AADT) is ≥ 2000 the edge lines must be wet-night visible, which is attained by creating a so-called profiled marking.

    The aim of the project was to investigate whether there is a difference in durability between a broken and a continuous edge line, and to investigate whether there is a difference in performance and durability between different types of profiled markings. In the first part of the project, broken and continuous edge lines were applied on a public two-lane road. The performance of the markings was followed up by annual measurements of retroreflectivity RL and luminance coefficient Qd for four years. In the second part of the project, a test field with six different types of markings - one without and five with profile – were applied on a public road.

    Follow-up measurements of retroreflectivity RL on dry as well as on wet markings, and luminance coefficient Qd in dry conditions were carried out after one and two years. No difference in durability between broken and continuous edge lines was shown. Regarding profiled markings, a road marking with an embossed pattern had the best performance with respect to all three performance parameters. Profiled markings with diagonal squares (“stairs”) had better performance than markings with transversal lines.

  • 37.
    Fors, Carina
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Yahya, Mohammad-Reza
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Lundkvist, Sven-Olof
    Swedish National Road and Transport Research Institute.
    Tillståndsmätning av vägmarkeringars funktion 20142015Report (Other academic)
    Abstract [en]

    Measurements of road marking performance have been carried out from 21 May to 6 November 2014 on a sample of Swedish roads. The aim of the performance assessment is primarily to investigate to what extent the road markings fulfil the Swedish regulations. Besides, the assessment aims at comparing the road marking performance in different counties and regions, and to analyse the development over time, as performance assessments have been carried out to various extent since 2000. The results of the measurements in 2014 show that 39 per cent of the road marking objects fulfilled the requirements regarding dry road marking retroreflection. The corresponding figure for wet road markings was 21 per cent. With respect to dry road markings, Region Norr (North) and Region Väst (West) had the largest percentage of road marking objects that fulfilled the requirement, with 52 per cent each. Region Stockholm had the lowest percentage of road markings objects that fulfilled the requirements – only 12 per cent. Regarding wet road markings, the percentage of approved objects were 50 per cent in Region Norr (North) and in the range of 7–30 per cent in the other regions. A comparison over the years 2011–2014 shows a downward trend. The percentage of road marking length that fulfills the requirements for dry road markings has decreased from 70 per cent in 2011 to 60 per cent in 2014. The corresponding figures for the percentage of approved road marking objects are 52 per cent and 39 per cent, respectively. In four out of the six regions, the percentage of approved road marking objects has decreased from 2013 to 2014. In summary, the fulfilment of the requirements is in general low and there has been a downward trend since 2011. Furthermore, there is a substantial difference in results between the regions, where Region Norr (North), Region Väst (West) and Region Syd (South) have better results than the other regions. Region Stockholm has markedly worse results than the other regions. A total of 303 objects, each including two edge lines and one centre or lane line, i.e. three road marking objects, have been monitored using mobile equipment. The objects have been randomly selected, however in such a way that at least 14 objects per county have been included in the sample.

  • 38.
    Fors, Carina
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Yahya, Mohammad-Reza
    Swedish National Road and Transport Research Institute, Infrastructure, Measurement technology and engineering workshop.
    Lundkvist, Sven-Olof
    Swedish National Road and Transport Research Institute.
    Tillståndsmätningar av vägmarkeringar i Norden: en jämförelse mellan vägmarkeringars funktion i Norge, Sverige och Finland2015Report (Other academic)
    Abstract [en]

    The overall aim of the present study was to compile and compare road marking performance in Norway, Sweden and Finland, in order to disseminate knowledge. More specifically, the study aimed at investigating whether there are any differences in road marking performance between the countries, and whether there are any differences in road marking performance depending on traffic volume and road width. The results showed that road marking performance tended to be somewhat better in Norway and Sweden than in Finland. The average of the retroreflexion for dry edge markings were in Norway 179, in Sweden 177 and in Finland 142. Corresponding results for centre lines were in Norway 137 (yellow markings), in Sweden 164 (white marking) and in Finland 102 (white marking) and 107 (yellow marking), respectively. For wet edge markings, the retroreflexion was 45 in Norway and 31 in Sweden. In Finland, no data on wet markings was available. Furthermore, the results showed that the retroreflexion of the edge markings was independent of average annual daily traffic (AADT) and roadway width. Centre markings on roads with AADT<2000 had lower retroreflexion than centre markings on roads with larger traffic volume. A sample of 98–167 objects were selected from each country, where each object consisted of a 2–10 kilometre long stretch of road. All objects were two-lane roads, which were divided into five classes based on AADT and roadway width. For each object, the retroreflexion of both edge lines and the centre line was measured.

  • 39.
    Hallvig, David
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction. Chalmers Tekniska Högskola.
    Anund, Anna
    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.
    Kecklund, Göran
    Stockholms Universitet.
    Karlsson, Johan G.
    Autoliv Development AB.
    Wande, Mattias
    Chalmers Tekniska Högskola.
    Åkerstedt, Torbjörn
    Stockholms Univeristet, Karolinska institutet.
    Sleepy driving on the real road and in the simulator: A comparison2013In: Accident Analysis and Prevention, ISSN 0001-4575, E-ISSN 1879-2057, Vol. 50, 44-50 p.Article in journal (Refereed)
    Abstract [en]

    This study compared real driving with driving in a high fidelity, moving base, driving simulator with respect to driving performance, sleep related physiology (using electroencephalography and electrooculography) and subjective sleepiness during night and day driving for 10 participants.

    Sleepiness has been identified as one of the most important factors contributing to road crashes. However, almost all work on the detailed changes in behavior and physiology leading up to sleep related crashes has been carried out in driving simulators. It is not clear, however, to what extent simulator results can be generalized to real driving.

    The real road was emulated in the simulator. The results show that the simulator was associated with higher levels of subjective and physiological sleepiness than real driving. However, both for real and simulated driving, the response to night driving appears to be rather similar for subjective sleepiness and sleep physiology. Lateral variability was more responsive to night driving in the simulator, while real driving at night involved a movement to the left in the lane and a reduction of speed, both of which effects were absent in the simulator. It was concluded that the relative validity of simulators is acceptable for many variables, but that in absolute terms simulators cause higher sleepiness levels than real driving. Thus, generalizations from simulators to real driving must be made with great caution.

  • 40.
    Hallvig, David
    et al.
    Stockholms Universitet.
    Anund, Anna
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction. Linköpings Universitet.
    Fors, Carina
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kecklund, Göran
    Stockholms Universitet, Radboud University Nijmegen.
    Åkerstedt, Torbjörn
    Stockholms Universitet, Karolinska Institutet.
    Real driving at night: Predicting lane departures from physiological and subjective sleepiness2014In: Biological Psychology, ISSN 0301-0511, E-ISSN 1873-6246, Vol. 101, no 1, 18-23 p.Article in journal (Refereed)
    Abstract [en]

    Only limited information is available on how driving performance relates to physiological and subjective sleepiness on real roads. This relation was the focus of the present study. 33 volunteers drove for 90. min on a rural road during the afternoon and night in an instrumented car, while electroencephalography and electrooculography and lane departures were recorded continuously and subjective ratings of sleepiness were made every 5. min (Karolinska Sleepiness Scale - KSS). Data was analyzed using Bayesian multilevel modeling. Unintentional LDs increased during night driving, as did KSS and long blink durations(LBD). Lateral position moved to the left LDs were predicted by self-reported sleepiness and LBDs across time and were significantly higher in individuals with high sleepiness. Removal of intentional LDs, enhanced the KSS/LD relation. It was concluded that LDs, KSS, and LBDs are strongly increased during night driving and that KSS predicts LDs.

  • 41.
    Hjälmdahl, Magnus
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport.
    Vadeby, Anna
    Swedish National Road and Transport Research Institute, Traffic and road users, Traffic safety, society and road-user.
    Forsman, Åsa
    Swedish National Road and Transport Research Institute, Traffic and road users, Traffic safety, society and road-user.
    Fors, Carina
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Ceder, Gunnel
    National Board for Forensic Medicine, Linköping.
    Woxler, Per
    Östergötlands Läns Landsting, Psykiatriska kliniken.
    Kronstrand, Robert
    Linköpings universitet, Avdelningen för läkemedelsforskning.
    Effects of d-amphetamine on simulated driving performance before and after sleep deprivation2012In: Psychopharmacology, ISSN 0033-3158, E-ISSN 1432-2072, Vol. 222, no 3, 401-411 p.Article in journal (Refereed)
    Abstract [en]

    Stimulant drugs are commonly abused and also used to promote wakefulness, yet their effects on driving performance during sleep deprivation have not been thoroughly researched in experimental studies. The aims were to assess the effects on fundamental driving parameters during simulated driving of two doses of d-amphetamine and further to assess the interaction between d-amphetamine and sleep deprivation. A double-blind, placebo-controlled experiment including 18 healthy male volunteers was conducted. The participants felt more alert when taking a dose of d-amphetamine than when taking placebo, and the effect was stronger for the higher dose. However, the data did not show any evidence that taking d-amphetamine prevented the subjects from becoming successively sleepier during the night. A significant main effect of the dose was found for three out of the five primary indicators where the lower dose led to improved driving. These indicators were crossing-car reaction time, and coherence and delay from a car-following event. Regarding sleep deprivation, a main effect was found for four of the primary indicators and three of the secondary indicators. The results showed overall impaired driving with respect to standard deviation of lateral position and delay in reaction time when the sleep-deprived conditions were compared to the alert condition. We found no interactions between dose and sleep deprivation for any of the performance indicators. Our results suggest that administration of d-amphetamine does not compensate for impairment of driving due to fatigue. The positive effects of 10 mg were not further improved or even sustained when increasing the dose to 40 mg.

  • 42.
    Hof, Tineke
    et al.
    TNO, The Netherlands.
    Wilschut, Ellen S
    TNO, The Netherlands.
    Schwartz, Johanna
    Stress research institute, Sweden.
    Ingres, Mikael
    Stress research institute, Sweden.
    Fors, Carina
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Rodling Wahlström, Marie
    Uneå Universitet.
    Philip, Pierre
    SANPSY, France.
    Taillard, Jacques
    SANPSY, France.
    Davenne, Damien
    SANPSY, France.
    Gauthier, Antoine
    SANPSY, France.
    Lericollais, Romain
    SANPSY, France.
    Phillips, Ross Oven
    Institute of Transport Economics (TØI), Norway.
    Sagberg, Fridulv
    Institute of Transport Economics (TØI), Norway.
    Caljouw, Carien J.
    TNO, The Netherlands.
    Valk, Pierre J.L.
    TNO, The Netherlands.
    Multilevel Intervention Mapping with sleepiness in focus2011Report (Other academic)
    Abstract [en]

    Driver fatigue is an important risk factor in traffic safety and an issue for both private and professional drivers. This report provides an analysis of risk factors related to fatigue-related road accidents, and describes intervention goals at multiple levels in order to reduce sleepy driving among drivers. Private drivers who are on their way to or from their holiday were assigned as the specific target group.

  • 43.
    Johansen, Trond Cato
    et al.
    Ramböll.
    Fors, Carina
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL.
    Nygårdhs, Sara
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL.
    Lundkvist, Sven-Olof
    Nordic certification of road marking materials in Denmark 2015–20162016Report (Other academic)
    Abstract [en]

    A Nordic certification system for road marking materials was introduced in 2015. In the first stage, the certification system applies to Denmark, Norway and Sweden. In these countries, a documented product approval will be required in order to use a road marking material on roads managed by the national road authorities. Product approval will be based on monitored and documented performance measurements of material samples applied on test fields on public roads.

    Today, the certification system includes two test sites: one in Sweden and one in Denmark. However, the present report only deals with the certification in Denmark; the results from the Swedish test site will be presented in another report. The first round of material application took place in 2015, while follow-measurements were carried out around one year later, in 2016. At this point in time, the wheel passage classes P0, P1, P2 and P3 were reached at the Danish test site. In other words, the report presents which materials were certified for the mentioned P classes in 2016.

  • 44.
    Johansen, Trond Cato
    et al.
    Ramböll.
    Fors, Carina
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL.
    Nygårdhs, Sara
    Swedish National Road and Transport Research Institute, Traffic and road users, Trafikanttillstånd, TIL.
    Lundkvist, Sven-Olof
    Nordic certification of road marking materials in Sweden 2015−20162016Report (Other academic)
    Abstract [en]

    A Nordic certification system for road marking materials was introduced in 2015. In the first stage, the certification system applies to the countries of Denmark, Norway and Sweden. In these countries, a documented product approval will be required in order to use a road marking material on roads managed by the national road authorities. Product approval will be based on monitored and documented performance measurements of material samples applied on test fields on public roads.

    Today, the certification system includes two test sites: one in Sweden and one in Denmark. However, the present report only deals with the certification in Sweden. The first round of material application took place in 2015, while follow-up measurements were carried out around one year later, in 2016. At this point in time, the wheel passage classes P0, P1, P2, P3 and P4 were reached at the Swedish test site. In other words, the report presents which materials were certified for the mentioned P-classes in 2016.

  • 45.
    Kecklund, Göran
    et al.
    Stockholms Universitet.
    Radun, Igor
    Stockholms Universitet.
    Ingre, Michael
    Stockholms Universitet.
    Fors, Carina
    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.
    Anund, Anna
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Bus drivers' working hours and their effects on sleep and fatigue2014In: Journal of Sleep Research, ISSN 0962-1105, E-ISSN 1365-2869, Vol. 23, 286-287 p.Article in journal (Refereed)
  • 46.
    Kettwich, Carmen
    et al.
    Karlsruhe Institute of Technology, Light Technology Institute (LTI) .
    Fors, Carina
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Driver gaze behaviour at cycle crossings in daylight and at night2011Report (Other academic)
    Abstract [en]

    The aim of the present study was to evaluate a method for assessment of drivers’ gaze behaviour and to study gaze and driving behaviour at cycle crossings after right turns. Twenty-one participants were equipped with a head-mounted eye tracking system and were instructed to drive along a predetermined test route in an urban area, in daylight and at night. Five cycle crossings after right turn were passed. At the last cycle crossing during the second driving session, a cyclist was approaching the crossing. After each driving session, the participants filled in a questionnaire. Gaze behaviour just before and at the cycle crossing was analyzed. The participants tended to look towards the cycle path more in daylight than at night. When a cyclist was approaching the crossing, the participants looked at her earlier in daylight than at night. Using a head-mounted eye tracking system worked well for analysis of gaze behaviour towards well-defined objects. The system worked well in daylight as well as at night. A disadvantage is that the system reduces the drivers’ ability to turn their head.

  • 47.
    Kircher, Katja
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Ahlström, Christer
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    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.
    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.
    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.
    Countermeasures against dangerous use of communication devices while driving –: a toolbox2012Report (Other academic)
    Abstract [en]

    This report outlines possible means to reduce the dangerous usage of mobile phones and other communication devices while driving. An important aspect of this commission was to demonstrate alternatives to legislation. The suggested countermeasures cover several areas. One is technical solutions, including countermeasures directed towards the infrastructure, the vehicle and the communication device. Another area includes education and information and describes different ways to increase knowledge and understanding. Furthermore, there are different possibilities for how society can influence the behaviour of individuals, both via bans, recommendations and incentives. The usage of communication devices while driving has both advantages and disadvantages. How to deal with device usage is a complex problem, and it is unlikely that one single countermeasure can provide a complete solution. One countermeasure may even depend on the implementation of others. The exact effect of most countermeasures is hard to predict, and possible side effects may occur. It is therefore necessary to be pragmatic, meaning that countermeasures whose advantages outweigh their disadvantages should be implemented. Also, different countermeasures can reinforce each other which may attenuate negative side effects. It is our opinion that a combination of different countermeasures – which educate and inform the driver while at the same time support him or her in a safe usage of communication devices – is preferable to a law against communication device usage while driving. Continuous follow-ups are necessary to ensure the outcome of implemented countermeasures.

  • 48.
    Kircher, Katja
    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.
    Ahlström, Christer
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Continuous versus intermittent presentation of visual eco-driving advice2014In: Transportation Research Part F: Traffic Psychology and Behaviour, ISSN 1369-8478, E-ISSN 1873-5517, Vol. 24, 27-38 p.Article in journal (Refereed)
    Abstract [en]

    Automatic eco-driving advice has the potential to improve fuel economy and reduce emissions. However, providing eco-driving information to the driver will inevitably draw attention away from the driving task. The objective of this research is to investigate the effects of intermittent versus continuous visual eco-driving information on glance behaviour in an attempt to find the best approach to display eco-driving information from a traffic safety perspective.

    Twenty-eight truck drivers drove on a village road, a rural road and a motorway section in an advanced moving base truck simulator. A number of situations with relevance for eco-driving, such as traffic lights, crests, changes in posted speed limits, and a motorway entrance, were investigated. The level of difficulty of the traffic situations varied. Four conditions were tested: baseline without eco-driving information, intermittent feedback, continuous feedback and self-selected feedback (personalised settings selected by the driver).

    As expected, the drivers looked at the eco-driving system when it was active, and more so when the traffic situation was less demanding. Importantly, drivers waited longer with their first glance at the display when the traffic situation was more complex. In conclusion, intermittent information is recommended over continuous information as it leads to shorter dwell times, and as it is easier for the system designer to control when the periods of increased glance frequency occur, by presenting the information in strategically advantageous locations that are not demanding for the driver.

  • 49.
    Kircher, Katja
    et al.
    Swedish National Road and Transport Research Institute.
    Fors, Carina
    Swedish National Road and Transport Research Institute.
    Berg, Ylva
    Fokus på halka: fokusgruppsresultat om attityder kring framtida halkinformationssystem2008Report (Other academic)
    Abstract [sv]

    SRIS (Slippery Road Information System) is a Swedish project that will be accomplished during 2006-2008. The project aims to develop a system to evaluate winter road conditions in real-time. Information about the road condition is received both from the road weather information stations that are located along the roads and from ordinary vehicles running on the roads. The road friction is estimated from the vehicle's existing sensors and the information is sent to a central unit that merges all information and calculates a low friction index, which is presented on a web page. Further development of the system could make it possible to send information about low friction to drivers, when they are driving. Information about slipperiness could potentially also be useful for the winter maintenance workforce. In order to investigate professional drivers' and winter maintenance workers' attitudes towards slippery road information systems, two focus groups were conducted. Five winter maintenance workers participated in the first focus group, while the second group consisted of eight professional drivers of heavy vehicles.

  • 50.
    Kircher, Katja
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Gregersen, Nils Petter
    Swedish National Road and Transport Research Institute, Society, environment and transport, Mobility, actors and planning processes.
    Ahlström, Christer
    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.
    Hjälmdahl, Magnus
    Swedish National Road and Transport Research Institute, Society, environment and transport.
    Jansson, Jonas
    Swedish National Road and Transport Research Institute, Traffic and road users.
    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.
    Åtgärder mot trafikfarlig användning av kommunikationsutrustning under körning: en verktygslåda2012Report (Other academic)
    Abstract [en]

    This report outlines possible means to reduce the dangerous usage of mobile phones and other communication devices while driving, while at the same time preserve the positive effects. The suggested countermeasures cover several areas and are intended to function as alternatives to banning device usage. One is technical solutions, including countermeasures directed towards the infrastructure, the vehicle and the communication device. Another area includes education and information and describes different ways to increase knowledge and understanding. Furthermore, there are different possibilities for how society can influence the behaviour of individuals, both via bans, recommendations and incentives. We want to point out that the usage of communication devices while driving has both advantages and disadvantages. How to deal with device usage is a complex problem, and it is unlikely that one single countermeasure can provide a complete solution. One countermeasure may even depend on the implementation of others. The exact effect of most countermeasures is hard to predict, and possible side effects may occur. It is therefore necessary to be pragmatic, meaning that countermeasures whose advantages outweigh their disadvantages should be implemented. Also, different countermeasures can reinforce each other which may attenuate negative side effects.

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