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  • 151.
    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, p. 27-38Article 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.

  • 152.
    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.

  • 153.
    Kircher, Katja
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kircher, Albert
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Ahlström, Christer
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Results of a field study on a driver distraction warning system2009Report (Other academic)
    Abstract [sv]

    The main goal of the distraction and drowsiness field study was to evaluate a system for detecting driver distraction and drowsiness. This report focuses on the results of the study, indicating how a distraction warning system influenced glance behaviour. A vehicle was instrumented with an automatic eye tracker and other sensors. Seven participants drove the vehicle during one month each. During the first ten days a baseline was collected. Afterwards the warnings were activated, which involved that the drivers received a vibration in the seat when the algorithm determined that they had looked away from the forward roadway for a too long time. The main finding was that the drivers' gaze behaviour was not influenced much by the distraction warnings. The drivers received distraction warnings at about the same frequency during the treatment and the baseline phase. Performance indicators like "percent road centre" and others did not change from baseline to treatment phase. The average percentage of very long glances decreased slightly in the treatment phase, suggesting that the warning had an effect on the more extreme glance behaviour. There are also indications that the system helped prevent further extended glances away from the road immediately after a warning was issued.

  • 154.
    Kircher, Katja
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kircher, Albert
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Claezon, Fredrich
    Saab Automobile.
    Distraction and drowsiness - a field study: technical report2009Report (Other academic)
    Abstract [en]

    The main goal of the distraction and drowsiness field study was to evaluate a system for detecting driver distraction and drowsiness. This report focuses on the system implementation and the algorithms detecting distraction and drowsiness. A vehicle was instrumented with video cameras, an automatic eye tracker and GPS receivers. Further data were read from the CAN bus of the car. The data were logged continuously with high frequency. The log system operated autonomously. Seven participants drove the vehicle during one month each. During the first ten days a behavioural baseline was collected. Afterwards the warnings were activated, such that the drivers received distraction warnings in form of a vibration in the seat when the algorithm determined that they had looked away from the forward roadway too much. A separate algorithm judged whether the drivers were drowsy or not. Questionnaires were administered on three occasions during the course of the study. No major problems were encountered during the field operational test (FOT), but a number of smaller problems had to be solved. However, in the end of the data collection period the computer installed in the car became more and more unstable, which led to increased data loss.

  • 155.
    Kircher, Katja
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Larsson, Annika F L
    Lunds Universitet.
    Andersson Hultgren, Jonas
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Tactical driving behaviour with different levels of automation2014In: IEEE transactions on intelligent transportation systems (Print), ISSN 1524-9050, E-ISSN 1558-0016, Vol. 15, no 1, p. 158-167Article in journal (Refereed)
    Abstract [en]

    This paper investigated how different types of automation affect tactical driving behavior, depending on trust in the system. Previous research indicates that drivers wait for automation to act, delegating the monitoring of traffic situations. This would be especially true for those who have more trust in automation. Behavioral and gaze data from 30 participants driving an advanced simulator were recorded in four driving conditions, namely, manual driving, intentional car following, adaptive cruise control (ACC), and ACC with adaptive steering. Measures of trust in the systems were recorded with a questionnaire.

    Three fairly common traffic events requiring a driver response were analyzed. Trust in automation was high among the participants, and no associations between trust levels and behavior could be found. Drivers seem to make informed choices on when to let the automation handle a situation and when to switch it off manually or via the vehicle controls. If drivers did not expect the system to be able to handle the situation, they usually resumed control before the automation reached its limits. If the automation was expected to be able to deal with the situation, control was usually not resumed. In addition, situations were dealt with in a tactically different manner with automation than without. Controlling the car with automation systems is thus accepted by drivers as being a different undertaking than driving in manual mode.

  • 156.
    Kircher, Katja
    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.
    The influence of lighting, wall colour and inattention on traffic safety in tunnels: a simulator study2011Report (Other academic)
    Abstract [en]

    Even though the crash risk in tunnels is rather lower than on the open road network, crash consequences can be very severe. Therefore it is of high importance to assure high safety standard in tunnels, which includes, but is not limited to, an appropriate illumination. The aim of this study was to investigate in which way different levels of illumination and brightness of the tunnel walls influence the behaviour of attentive and inattentive drivers.

    The study was conducted in the Simulator III at VTI, which is a high-fidelity simulator with linear motion in lateral direction. A within-subjects design was employed, and 24 participants took part in the tests. Illumination was varied on three levels and tunnel wall colour and driver attention were varied on two levels each. Driving data, eye tracking data and subjective data were collected and analysed for an overtaking event and for an event-free driving situation.

    Bright walls were more important for experienced safety and comfort than high illumination level, as long as the illumination was sufficiently bright. Further, driving behaviour and gaze behaviour were heavily influenced by driver state, with distracted drivers showing more unsafe behaviour. Additionally, bright walls received slightly lower demand ratings than dark walls.

  • 157.
    Kircher, Katja
    et al.
    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.
    Ahlström, Christer
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Mobile telephones and other communication devices and their impact on traffic safety: a review of the literature2011Report (Other academic)
    Abstract [en]

    VTI was commissioned by the Swedish Government to compile relevant research on mobile phone and other communication device usage whilst driving. Thus, a sub-set of those activities that can distract a driver in traffic are treated in the compilation.

    A review of several hundred publications reveals that the topic is very complex. Even though a large number of controlled studies show that using a mobile telephone while driving has a negative impact on driving performance, this was not reflected by a strong increase in crash rates in real traffic. Both the conversation itself and manipulating a telephone have negative effects on driving performance. When writing a SMS or using a telephone in a similar manner the driver takes the eyes off the road, often several times consecutively, and at times for longer periods of time. This results in decreased control of the vehicle and an increased risk that the driver misses crucial events in traffic. During a telephone conversation the driver does tend to look at the road, but nevertheless also conversation research has found prolonged reaction times and missed traffic events. Many drivers think that it is safer to use a hands-free set than a handheld telephone, but this has not been confirmed by the available research. Most EU countries have hands-free requirements, however, many drivers do not comply with the legislation. Bans on handheld mobile phones and on texting when driving do not appear to reduce the number of crashes.

  • 158.
    Kircher, Katja
    et al.
    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.
    Ahlström, Christer
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Mobiltelefoner och andra kommunikationsenheter och deras påverkan på trafiksäkerheten: en litteraturgenomgång2011Report (Other academic)
    Abstract [sv]

    VTI har fått i uppdrag av regeringen att sammanställa relevant forskning på området användande av mobiltelefon och annan kommunikationsutrustning under körning. Sammanställningen handlar alltså om en delmängd av aktiviteter som kan distrahera en bilförare från trafiken.

    En genomgång av flera hundra publikationer visar att ämnet är mycket komplext. Trots att ett stort antal kontrollerade studier visar att mobiltelefoni påverkar körprestationen negativt så har detta inte återspeglats i samma utsträckning i antalet trafikolyckor. Både själva samtalet och hanterandet av telefonen kan påverka körförmågan negativt. Att skriva ett sms eller på liknande sätt interagera med telefonen leder till att föraren tittar bort från vägen, ofta flera gånger i rad och ibland under lång tid. Resultatet är minskad kontroll över fordonet och en ökad risk för att föraren missar viktiga händelser i trafiken. Under ett samtal tittar föraren visserligen på vägen, men även här ser man försämrade reaktionstider och en nedsatt förmåga att ta till sig information. Många förare tror att det är säkrare med handsfree jämfört med handhållen telefon; forskningen har dock inte kunnat visa att det är säkrare att använda handsfree-utrustning. De flesta EU-länder tillåter endast handsfree-telefoni, men många förare följer inte lagarna, och lagstiftningen verkar inte leda till minskat antal olyckor.

  • 159.
    Kottenhoff, Karl
    et al.
    KTH.
    Sundström, Jerker
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Samband mellan körstil och åkkomfort: förbättringspotentialen inom kollektivtrafiken. Kortversion2011Report (Other academic)
    Abstract [en]

    Ride comfort constitutes part of the total comfort experience of a journey. It is a result of the interaction between the characteristics of the infrastructure and those of the vehicle, and not least a result of the driver’s handling. Poor ride comfort generally leads to low attractiveness of the public transportation system, mainly due to travelers being less relaxed and even unableto use the traveling time for reading. The motions of the vehicle can cause some passengers todevelop motion sickness and even tripping or fall accidents occur due to difficulty to keepbalance.The project aims to improve the knowledge level for the relationship between drivers' drivingstyle and ride comfort, including motion sickness. Comparisons of the ride comfort are madebetween bus and rail services and differences between drivers are also studied. A concretegoal is to provide basis for driver training and new support systems for drivers. Differencesand similarities between "eco driving" and good ride comfort are briefly addressed.The project began with interviews of bus and subway travelers and with measurements ofvehicle motions during normal service operation. In the autumn 2009, in-field experimentswere performed with test subjects who evaluated different driving styles in terms of comfort.The results showed that heavy braking, cornering forces, longitudinal jerks and uneven speedmean a lot to passengers' valuation. The results from these experiments show that in all thesedriving styles give rise to significant decreases of the perceived comfort.Correlation and regression analysis was then used to develop indicators for quantitativeanalysis of travel with public transport. The four indicators that were produced essentiallyreveal the sensitivity for; 1) longitudinal acceleration and braking, 2) longitudinal jerks, 3)cornering forces, and 4) uneven speed, so-called "Pump driving". Further, these indicators were used to assess some hundred measurement runs with accelerometers in both buses andmetro cars in normal service.

  • 160.
    Kottenhoff, Karl
    et al.
    KTH.
    Sundström, Jerker
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Samband mellan körstil och åkkomfort: förbättringspotentialen inom kollektivtrafiken. Lång version2011Report (Other academic)
    Abstract [en]

    Ride comfort constitutes part of the total comfort experience of a journey. It is a result of the interaction between the characteristics of the infrastructure and those of the vehicle, and not least a result of the driver’s handling. Poor ride comfort generally leads to low attractiveness of the public transportation system, mainly due to travelers being less relaxed and even unable to use the traveling time for reading. The motions of the vehicle can cause some passengers to develop motion sickness and even tripping or fall accidents occur due to difficulty to keep balance. The project aims to improve the knowledge level for the relationship between drivers' driving style and ride comfort, including motion sickness. Comparisons of the ride comfort are made between bus and rail services and differences between drivers are also studied. A concrete goal is to provide basis for driver training and new support systems for drivers. Differences and similarities between "eco driving" and good ride comfort are briefly addressed.

  • 161.
    Larsson, Annika F L
    et al.
    Lunds Universitet.
    Kircher, Katja
    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.
    Learning from experience: Familiarity with ACC and responding to a cut-in situation in automated driving2014In: Transportation Research Part F: Traffic Psychology and Behaviour, ISSN 1369-8478, E-ISSN 1873-5517, Vol. 27, p. 229-237Article in journal (Refereed)
    Abstract [en]

    Response times to risky events have been seen to increase with the use of adaptive cruise control (ACC). It has been unclear whether driver experience with ACC mediates this increase. We compare driving in a cut-in event in a simulator both with and without system support, studying ACC as well as ACC with automatic steering. 31 participants were tested in a repeated-measures design, 10 novices and 21 previously experienced with ACC. There was no difference between responding to ACC with and without automatic steering for either group. As expected, we found an increase in response times when driving with system support for both ACC-experienced drivers and ACC-novices. However, this effect was significantly lower for those previously experienced with ACC. This indicates that there is an element of learning involved not only in knowing about system limitations, but also in responding to potential hazards

  • 162.
    Leon-Dominguez, Umberto
    et al.
    Ctr Brain Injury Rehabil CRECER.
    Solis-Marcos, Ignacio
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Barrio-Alvarez, Elena
    Autonomous University of Madrid.
    Leon-Carrion, Jose
    University of Sevilla.
    The impact of cognitive impairment on driving ability: The role of executive functioning2016In: Brain Injury, ISSN 0269-9052, E-ISSN 1362-301X, Vol. 30, no 5-6, p. 490-490, article id 0027Article in journal (Refereed)
  • 163.
    Levin, Lena
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Mobility, actors and planning processes.
    Dukic, Tania
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Henriksson, Per
    Swedish National Road and Transport Research Institute, Society, environment and transport, Mobility, actors and planning processes.
    Mårdh, Selina
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Sagberg, Fridulv
    TØI.
    Older car drivers in Norway and Sweden: studies of accident involvement, visual search behaviour, attention and hazard perception2009Report (Other academic)
    Abstract [en]

    Hazardous situations for older drivers and older drivers' accident involvement and visual behaviour in complex traffic situations have been studied in the reported research project. Three main methods have been used: 1) a thorough accident analysis of police reported accidents in Norway, 2) a literature study on existing research on older drivers' behaviour (i.e. cognitive aspects on car driving) and accident involvement, and 3) experimental studies comprising visual and perception tests accomplished in Norway and Sweden and a field study on the road, accomplished in Sweden. In the experimental study and in the field study it was found significantly more individual differences among the older than among the younger drivers in the samples from Norway and Sweden. From in depth analyses of fatal crashes in Norway during the years 2005-2007 it was found that tiredness was the most often suspected cause of the accident among the group aged 35-55 years (28 %) and the second most often suspected cause in the group aged 75+ (19 %). Illness could be the cause of the accident twice as often among the older drivers (28 %) as in the younger control group (14 %). Concerning suicide, the situation could be the reverse with more deliberate actions among the younger (11 %) compared to the older drivers (6 %)

  • 164.
    Levén, Anna
    et al.
    Linköpings Universitet.
    Lyxell, Björn
    Andersson, Jan
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Danielsson, Henrik
    Linköpings Universitet.
    Pictures as cues or as support to verbal cues at encoding and execution of prospective memories in individuals with intellectual disability2014In: Scandinavian Journal of Disability Research, ISSN 1501-7419, E-ISSN 1745-3011, Vol. 16, no 2, p. 141-158Article in journal (Refereed)
    Abstract [en]

    This study focused on prospective memory in persons with intellectual disability and age-matched controls. Persons with intellectual disability have limited prospective memory function. We investigated prospective memory with words and pictures as cues at encoding and retrieval. Prospective and episodic memory was estimated from Prospective Memory Game performance. Pictures at retrieval were important for prospective memory in particular in the intellectual disability group. Prospective memory performance imposed a cost to Episodic Memory (ongoing task) performance in the intellectual disability group. This group was outperformed by the control group on working memory, time reproduction, time concepts, and Raven's coloured progressive matrices. To conclude, pictures at retrieval improve prospective memory performance compared to words as cues. This can be essential for the intellectual disability group likely due to limited episodic and working memory capacity and the ability to switch attention.

  • 165.
    Linder, Astrid
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Traffic safety, society and road-user.
    Dukic, Tania
    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.
    Matstoms, Ylva
    Swedish National Road and Transport Research Institute.
    Mårdh, Selina
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Sundström, Jerker
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Vadeby, Anna
    Swedish National Road and Transport Research Institute, Traffic and road users, Traffic safety, society and road-user.
    Wiklund, Mats
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Östlund, Joakim
    Swedish National Road and Transport Research Institute.
    Methods for the evaluation of traffic safety effects of Antilock Braking System (ABS) and Electronic Stability Control (ESC): a literature review2007Report (Other academic)
    Abstract [sv]

    In today's vehicles, active safety systems are introduced addressing a large variety of safety issues such as providing optimal stability control, braking effect, preventing spin and rollover, as well as collision avoidance, to mention just a few. In this study a literature review was performed in order to establish how the traffic safety performances of active safety systems with focus on Antilock Braking System (ABS) and Electronic Stability Control (ESC) are assessed. The areas covered were statistical evaluation, testing and driver behaviour. The literature review showed that in particular statistical methods, based on odds ratios, had been used in order to evaluate the traffic safety effect. In order to evaluate the effect of ESC in physical testing there are several test methods described in this report. Estimations of driver behaviour effects have been carried out by surveys among vehicle owners. Experiments performed in field or in simulator have also been found in the literature. From EU projects a variety of measures and test methods are available for assessment of driver behavioural effects.

  • 166.
    Lundkvist, Sven-Olof
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Beurteilung des LTL-M: mobile Messung von Strassenmarkierungen2010Report (Other academic)
    Abstract [de]

    Das LTL-M, eine Ausrüstung für die mobile Messung der Rückstrahlung von Straßenmarkierungen, wurde von DELTA Light & Optics in Dänemark entwickelt. Dieses Gerät setzt ein anderes optisches Prinzip als das bisher übliche mobile Gerät ein. das Ecodyn 30. Das optische System des LTL-M könnte zu höherer Genauigkeit und besserer Wiederholbarkeit führen. Durch simultane Messungen mit den beiden mobilen Geräten und als Referenz mit dem Irlandmessgerät LTL-2000 wurden die Genauigkeit und Wiederholbarkeit des LTL-M und des Ecodyn 30 eingeschätzt. Die Messungen erfolgten im Labor an Proben von Straßenmarkierungen und in einer Feldstudie an durchgehenden und unterbrochenen Seitenlinien. Die Schlussfolgerung dieser Studie ist, dass das LTL-M mit weniger systematischen und Zufallsfehlern als das Ecodyn 30 misst. Außerdem ist die Wiederholbarkeit des LTL-M besser als die Wiederholbarkeit des Ecodyn 30.

  • 167.
    Lundkvist, Sven-Olof
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Performance assessment of road equipment: state of the art2012Report (Other academic)
    Abstract [en]

    In the future, if new mobile instruments will be developed condition assessments of road equipment might become valuable tools for deciding when and where maintenance is needed most.

    The conclusion of this survey is that condition assessment of road equipment, such as measurement of luminance and illuminance of road lighting and measurement of retroreflectivity of road signs are rare. This fact is to a large extent due to the lack of suitable instruments.

    In order to maintain the performance of road equipment, it is important to take correct action at correct time. This means that repair or renewal of the equipment in question must be carried out when the performance has reached the lowest acceptable end user service level (EUSL). The time of this occurrence should be based on a management model or a condition assessment, which involves physical measurement and/or visual inspection.

    This report shows the state of the art regarding condition assessment of road equipment. It deals with monitoring methods, maintenance measures and acceptable end user service levels in seven European countries: Belgium, Croatia, Denmark, Germany, the Netherlands, Sweden and UK. The work has been limited to the more important types of road equipment: road markings, road studs, delineator posts, fixed traffic signs, variable message signs (VMS) and road lighting.

  • 168.
    Lundkvist, Sven-Olof
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Engen, Thomas
    SINTEF, Norge.
    Rajamäki, Riikka
    VTT, Finland.
    Helmers, Gabriel
    Nygårdhs, Sara
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kantstolpars effekt på trafikantbeteendet2014Report (Other academic)
    Abstract [en]

    In order to improve the visual guidance in night-time traffic most Nordic roads are equipped with delineator posts. The configuration of these posts vary between the countries; as an example the distance between two delineator posts is 100 metres in Denmark, while it is 50 metres in Sweden. The aim of the present study was to investigate which delineator post configuration that gives the best driving behavior. Furthermore, the optimal visibility distance of the retro-reflector of the post was estimated. The results can be used for a harmonization of the Nordic regulations regarding delineator posts. The study was conducted in the VTI and SINTEF driving simulators. The study of configuration (VTI) was validated on the real road in Finland by VTT. In the VTI simulator subjects drove in the dark a loop containing seven different delineator posts configurations, while the study at SINTEF used a loop where the retro-reflectors of the posts had a night-time visibility distance of 100, 200 or 400 metres. In both simulators the speed was registered continuously. The results show that the configuration which today is used in Denmark is to prefer. This configuration gives equal or better driving behavior than other configurations, but to a lower price. The optimal visibility distance of the retro-reflectometer was estimated to 100-200 metres.

  • 169.
    Lundkvist, Sven-Olof
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Henriksson, Per
    Swedish National Road and Transport Research Institute, Society, environment and transport, Mobility, actors and planning processes.
    Yahya, Mohammad Reza
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Tillståndsmätningar av vägmarkeringars funktion år 2011: sammanfattande resultat från Sverige2012Report (Other academic)
    Abstract [en]

    VTI has performed measurements for condition assessment of road marking performance in Sweden 2011. The measurements were carried out using the mobile reflectometer Ecodyn 30 to measure dry road marking retroreflectivity. The measurements were supplemented with an estimation of wet road marking performance. From the results, the following conclusions were drawn:

    Dry road marking retroreflectivity

    - On European highways with ADT (Average Daily Traffic) more or equal to 4,000 vehicles per day, 53 per cent of the measured objects fulfilled the requirements in the Swedish regulations.

    - On other European highways and national roads the corresponding figure was 47 per cent.

    - On county roads 49 per cent of the objects were approved.

    - The performance of the road markings was best in regions Norr, Öst och Syd, with Syd as the best one (significantly better than Öst, however, the Syd result was not significantly different in comparison with Norr). In region Väst about half of the road markings were approved while the worst performance was found in the regions Mitt and Stockholm.

    Wet road marking retroreflectivity

    - On European roads with ADT more or equal to 4,000 vehicles per day, 44 per cent of the measured objects fulfilled the requirements in the Swedish regulations.

    - The performance was best in regions Väst and Syd (there were no significant differences between them). In the other regions (Norr, Mitt, Stockholm and Öst) the performance was worse.

    The reports for each region are the following:

    VTI notat 8:1-2012 – Condition assessment of road markings of Region Syd in Sweden in 2011.

    VTI notat 8:2-2012 – Condition assessment of road markings of Region Väst in Sweden in 2011.

    VTI notat 8:3-2012 – Condition assessment of road markings of Region Öst in Sweden in 2011.

    VTI notat 8:4-2012 – Condition assessment of road markings of Region Stockholm in Sweden in 2011.

    VTI notat 8:5-2012 – Condition assessment of road markings of Region Mitt in Sweden in 2011.

    VTI notat 8:6-2012 – Condition assessment of road markings of Region Norr in Sweden in 2011

  • 170.
    Lundkvist, Sven-Olof
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Henriksson, Per
    Swedish National Road and Transport Research Institute, Society, environment and transport, Mobility, actors and planning processes.
    Yahya, Mohammad Reza
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Tillståndsmätningar av vägmarkeringars funktion år 2011: Trafikverket Region Mitt2012Report (Other academic)
    Abstract [en]

    This note presents the results of condition assessment of road marking performance in Region Mitt (Middle), Sweden 2011. The measurements were carried out during the period 18 June to 15 October by the use of the mobile reflectometer Ecodyn 30 to measure dry road marking retroreflectivity. Moreover, the reflectometer was supplemented with an optocator for estimation of wet road marking performance. From the results, the following conclusions can be drawn.

    Dry road marking retroreflectivity:

    - On European highways with ADT (Average Daily Traffic) more or equal to 4,000 vehicles per day, 40% of the measured objects fulfilled the requirements in the Swedish regulations.

    - On other European highways and national roads the corresponding figure was 23%.

    - On county roads 28% of the objects were approved.

    - The performance of the road markings was best in Jämtland county. Gävleborg county had a higher percentage of approved road markings than Dalarna county, whose performance was similar to Västernorrland county.

    Wet road marking retroreflectivity:

    - On European highways with ADT more or equal to 4,000 vehicles per day, 25% of the measured objects fulfilled the requirements in the Swedish regulations.

    - The performance was equal in the two counties where wet road marking function was estimated.

  • 171.
    Lundkvist, Sven-Olof
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Henriksson, Per
    Swedish National Road and Transport Research Institute, Society, environment and transport, Mobility, actors and planning processes.
    Yahya, Mohammad Reza
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Tillståndsmätningar av vägmarkeringars funktion år 2011: Trafikverket Region Norr2012Report (Other academic)
    Abstract [en]

    This note presents the results of condition assessment of road marking performance in Region Norr (North), Sweden 2011. The measurements were carried out during the period 2-29 August by the use of the mobile reflectometer Ecodyn 30 to measure dry road marking retroreflectivity. Moreover, the reflectometer was supplemented with an optocator for estimation of wet road marking performance. From the results, the following conclusions can be drawn:

    Dry road marking retroreflectivity:

    - On European highways with ADT (Average Daily Traffic) more or equal to 4,000 vehicles per day, 43% of the measured objects fulfilled the requirements in the Swedish regulations.

    - On other European highways and national roads, the corresponding figure was 69%.

    - On county roads, 64% of the objects were approved.

    - The performance of the road markings in Norrbotten county was better than in Västerbotten county on European highways with ADT more or equal to 4,000 vehicles per day. The difference between these counties was not statistically significant concerning the two other road types.

    Wet road marking retroreflectivity:

    - On European highways with ADT more or equal to 4,000 vehicles per day, 36% of the measured objects fulfilled the requirement in the Swedish regulations.

    - The performance was better in Norrbotten county than in Västerbotten county.

  • 172.
    Lundkvist, Sven-Olof
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Henriksson, Per
    Swedish National Road and Transport Research Institute, Society, environment and transport, Mobility, actors and planning processes.
    Yahya, Mohammad Reza
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Tillståndsmätningar av vägmarkeringars funktion år 2011: Trafikverket Region Stockholm2012Report (Other academic)
    Abstract [en]

    This note presents the results of condition assessment of road marking performance in Region Stockholm, Sweden 2011. The measurements were carried out during the period 28 June-7 October by the use of the mobile reflectometer Ecodyn 30 to measure dry road marking retroreflectivity. Moreover, the reflectometer was supplemented with an optocator for estimation of wet road marking performance. From the results, the following conclusions can be drawn:

    Dry road marking retroreflectivity:

    - On European highways with ADT (Average Daily Traffic) more or equal to 4,000 vehicles per day, 38% of the measured objects fulfilled the requirements in the Swedish regulations (Stockholm county).

    - On other European highways and national roads the corresponding figure was 13% (Stockholm county).

    - On county roads 19% of the objects were approved.

    - The performance of the road markings on primary roads was better on Gotland than in Stockholm county. However, when taking all road types into account, there were no significant differences between the counties in the region.

    Wet road marking retroreflectivity:

    - On European highways with ADT more or equal to 4,000 vehicles per day, 29% of the measured objects (Stockholm county) fulfilled the requirements in the Swedish regulations.

  • 173.
    Lundkvist, Sven-Olof
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Henriksson, Per
    Swedish National Road and Transport Research Institute, Society, environment and transport, Mobility, actors and planning processes.
    Yahya, Mohammad Reza
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Tillståndsmätningar av vägmarkeringars funktion år 2011: Trafikverket Region Syd2012Report (Other academic)
    Abstract [en]

    This note presents the results of condition assessment of road marking performance in Region Syd (South), Sweden 2011. The measurements were carried out during the period 20 May to 21September by the use of the mobile reflectometer Ecodyn 30 to measure dry road marking retroreflectivity. Moreover, the reflectometer was supplemented with an optocator for estimation of wet road marking performance. From the results, the following conclusions can be drawn:

    Dry road marking retroreflectivity:

    - On European highways with ADT (Average Daily Traffic) more or equal to 4,000 vehicles per day, 74%

    of the measured objects fulfilled the requirements in the Swedish regulations.

    - On other European roads and national roads the corresponding figure was 61%.

    - On county roads 67% of the objects were approved.

    - The performance of the road markings in Kalmar county was worst. In the other counties, a similar percentage of the road markings were approved, however, was Skåne county significantly better than Jönköping county.

    Wet road marking retroreflectivity:

    - On European roads with ADT more or equal to 4,000 vehicles per day, 65% of

    the measured objects fulfilled the requirements in the Swedish regulations.

    - The performance was best in Blekinge county. For three of the other counties, Jönköping, Kronoberg and Skåne, no significant differences were found. Road markings in Kalmar county had the worst condition (however, the difference was not significant between the counties of Kalmar and Kronoberg).

  • 174.
    Lundkvist, Sven-Olof
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Henriksson, Per
    Swedish National Road and Transport Research Institute, Society, environment and transport, Mobility, actors and planning processes.
    Yahya, Mohammad Reza
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Tillståndsmätningar av vägmarkeringars funktion år 2011: Trafikverket Region Väst2012Report (Other academic)
    Abstract [en]

    This note presents the results of condition assessment of road marking performance in Region Väst (West), Sweden 2011. The measurements were carried out during the period 2-6 June by the use of the mobile reflectometer Ecodyn 30 to measure dry road marking retroreflectivity. Moreover, the reflectometer was supplemented with an optocator for estimation of wet road marking performance. From the results, the following conclusions can be drawn:

    Dry road marking retroreflectivity:

    - On European highways with ADT (Average Daily Traffic) more or equal to 4,000 vehicles per day, 59%

    of the measured objects fulfilled the requirements in the Swedish regulations.

    - On other European highways and national roads the corresponding figure was 50%.

    - On county roads 71% of the objects were approved.

    - The performance of the road markings in Halland county was better than in Västra Götaland county. The difference between Halland county and Värmland county as well as Värmland county and Västra Götaland county was not statistically significant.

    Wet road marking retroreflectivity:

    - On European highways with ADT more or equal to 4,000 vehicles per day, 54%

    of the measured objects fulfilled the requirements in the Swedish regulations.

    - The performance was better in Halland county and Värmland county than in Västra Götaland county. The difference between Halland county and Värmland county was not statistically significant.

  • 175.
    Lundkvist, Sven-Olof
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Henriksson, Per
    Swedish National Road and Transport Research Institute, Society, environment and transport, Mobility, actors and planning processes.
    Yahya, Mohammad Reza
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Tillståndsmätningar av vägmarkeringars funktion år 2011: Trafikverket Region Öst2012Report (Other academic)
    Abstract [en]

    This note presents the results of condition assessment of road marking performance in Region Öst (East), Sweden 2011. The measurements were carried out during the period 16 June to 20 September by the use of the mobile reflectometer Ecodyn 30 to measure dry road marking retroreflectivity. Moreover, the reflectometer was supplemented with an optocator for estimation of wet road marking performance. From the results, the following conclusions can be drawn:

    Dry road marking retroreflectivity:

    - On European highways with ADT (Average Daily Traffic) more or equal to 4,000 vehicles per day, 48% of the measured objects fulfilled the requirements in the Swedish regulations.

    - On other European highways and national roads the corresponding figure was 47%.

    - On county roads 78% of the objects were approved.

    - The performance of the road markings in Östergötland county was best and in Örebro county it was better than in Södermanland county. All other differences between the counties were not significant.

    Wet road marking retroreflectivity:

    - On European highways with ADT more or equal to 4,000 vehicles per day, 36% of the measured objects fulfilled the requirements in the Swedish regulations.

    - The performance was worst in Södermanland county. All other differences between the counties were not significant.

  • 176.
    Lundkvist, Sven-Olof
    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.
    Samband mellan hastighet och belysning2014Report (Other academic)
    Abstract [en]

    The relationship between spontaneous choice of speed and lighting level on streets with stationary light has been studied. On ten streets in Linköping, the speed of cars which were not disturbed by other traffic, was measured. These measurements were carried out both during daylight and darkness conditions, where the daylight condition measurements were used as reference. The dependent variable was the difference between speed in daylight and darkness. The hypothesis was that this difference would be high (including sign) on streets with high illuminance level and low on streets with lower lighting level. One important question was if low lighting levels would result in lower speeds that would compensate for the worse visibility of objects in or close to the street. If so, there would be a positive effect on energy and environment without making impairing traffic safety.

  • 177.
    Lundkvist, Sven-Olof
    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.
    Samband mellan vägbelysningsnivå och spontant vald hastighet: förstudie2013Report (Other academic)
    Abstract [en]

    If something in the road environment is improved, there is always a risk that the drivers will compensate for the better conditions by increasing speed. As an example, one study showed that the introduction of delineator posts in Finland increased the average speed by as much as 10 km/h on curvy roads. Another study, carried out in Norway, showed an increase in speed of 1 – 5 per cent when road lighting was put up. Therefore, one reasonable hypothesis is that speed will increase with increasing lighting level. The primary purpose with this study was to test a method for measurement of spontaneous choice of speed related to lighting level. This means studying the speed chosen by a driver when he or she is not disturbed by other traffic. Space mean speed was measured by the use of an instrumented vehicle which could register speed continuously. Furthermore, this vehicle was equipped with a video front camera which made it possible to afterwards reject measurements which were not undisturbed. Each subject drove the test road, which had an illumination level of 0 to 30 lx, at off-peak hours both in daylight and darkness. The speed limit on all test sections was 50 km/h, all sections dry and illuminated on one side, only. However, one section had no stationary lighting at all. The method for data collection worked out, but was slow. The results show a weak, but clear tendency to higher speed with higher illumination level. The number of subjects, six, were small, therefore significant results should not be expected.

  • 178.
    Lundkvist, Sven-Olof
    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.
    Yahya, Mohammad Reza
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Tillståndsmätningar av vägmarkeringars funktion år 2012: sammanfattande resultat från Sverige2013Report (Other academic)
    Abstract [en]

    This report summarizes the results of the condition assessment of road markings in Sweden 2012. The measurements have been carried out using the mobile system Road Marking Tester which mainly is built up of a reflectometer and an optocator. The two units register the retroreflectivity and the macro-texture of the road marking, respectively. From these measures, the retroreflectivity of a wet road marking can be predicted, which has been done on roads with ADT > 4000 vehicles. Measurements were accomplished on 292 objects in total, each approximately 10 km of length. The objects were chosen randomly and spread all over Sweden. In each object three longitudinal road markings were measured: two edge lines and one centre- or laneline.

  • 179.
    Lundkvist, Sven-Olof
    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.
    Yahya, Mohammad Reza
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Tillståndsmätningar av vägmarkeringars funktion år 2012: Trafikverket Region Mitt2013Report (Other academic)
    Abstract [sv]

    I föreliggande notat redovisas tillståndsmätningar av vägmarkeringars funktion. Det är en av sex notat som redovisar mätningar i olika delar av landet. Mätningarna har utförts med det mobila systemet Road Marking Tester, vars två centrala komponenter är en reflektometer av typ LTL-M och en optokator för mätning av vägmarkerings makrotextur. Från retroreflexionen och texturen har våta vägmarkeringar skattats på vägar med ÅDT > 4000 fordon. Sammanlagt har mätningar gjorts på 292 cirka 10 km långa objekt, vilka hade valts slumpmässigt, jämnt fördelade över hela landet. I varje objekt på tvåfältsväg mättes de tre delobjekten höger och vänster kantlinje samt mittlinjen.

  • 180.
    Lundkvist, Sven-Olof
    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.
    Yahya, Mohammad Reza
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Tillståndsmätningar av vägmarkeringars funktion år 2012: Trafikverket Region Norr2013Report (Other academic)
    Abstract [sv]

    I föreliggande notat redovisas tillståndsmätningar av vägmarkeringars funktion. Det är en av sex notat som redovisar mätningar i olika delar av landet. Mätningarna har utförts med det mobila systemet Road Marking Tester, vars två centrala komponenter är en reflektometer av typ LTL-M och en optokator för mätning av vägmarkerings makrotextur. Från retroreflexionen och texturen har våta vägmarkeringar skattats på vägar med ÅDT > 4000 fordon. Sammanlagt har mätningar gjorts på 292 cirka 10 km långa objekt, vilka hade valts slumpmässigt, jämnt fördelade över hela landet. I varje objekt på tvåfältsväg mättes de tre delobjekten höger och vänster kantlinje samt mittlinjen.

  • 181.
    Lundkvist, Sven-Olof
    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.
    Yahya, Mohammad Reza
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Tillståndsmätningar av vägmarkeringars funktion år 2012: Trafikverket Region Stockholm2013Report (Other academic)
    Abstract [sv]

    I föreliggande notat redovisas tillståndsmätningar av vägmarkeringars funktion. Det är en av sex notat som redovisar mätningar i olika delar av landet. Mätningarna har utförts med det mobila systemet Road Marking Tester, vars två centrala komponenter är en reflektometer av typ LTL-M och en optokator för mätning av vägmarkerings makrotextur. Från retroreflexionen och texturen har våta vägmarkeringar skattats på vägar med ÅDT > 4000 fordon. Sammanlagt har mätningar gjorts på 292 cirka 10 km långa objekt, vilka hade valts slumpmässigt, jämnt fördelade över hela landet. I varje objekt på tvåfältsväg mättes de tre delobjekten höger och vänster kantlinje samt mittlinjen.

  • 182.
    Lundkvist, Sven-Olof
    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.
    Yahya, Mohammad Reza
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Tillståndsmätningar av vägmarkeringars funktion år 2012: Trafikverket Region Syd2013Report (Other academic)
    Abstract [sv]

    I föreliggande notat redovisas tillståndsmätningar av vägmarkeringars funktion. Det är en av sex notat som redovisar mätningar i olika delar av landet. Mätningarna har utförts med det mobila systemet Road Marking Tester, vars två centrala komponenter är en reflektometer av typ LTL-M och en optokator för mätning av vägmarkerings makrotextur. Från retroreflexionen och texturen har våta vägmarkeringar skattats på vägar med ÅDT > 4000 fordon. Sammanlagt har mätningar gjorts på 292 cirka 10 km långa objekt, vilka hade valts slumpmässigt, jämnt fördelade över hela landet. I varje objekt på tvåfältsväg mättes de tre delobjekten höger och vänster kantlinje samt mittlinjen.

  • 183.
    Lundkvist, Sven-Olof
    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.
    Yahya, Mohammad Reza
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Tillståndsmätningar av vägmarkeringars funktion år 2012: Trafikverket Region Väst2013Report (Other academic)
    Abstract [sv]

    I föreliggande notat redovisas tillståndsmätningar av vägmarkeringars funktion. Det är en av sex notat som redovisar mätningar i olika delar av landet. Mätningarna har utförts med det mobila systemet Road Marking Tester, vars två centrala komponenter är en reflektometer av typ LTL-M och en optokator för mätning av vägmarkerings makrotextur. Från retroreflexionen och texturen har våta vägmarkeringar skattats på vägar med ÅDT > 4000 fordon. Sammanlagt har mätningar gjorts på 292 cirka 10 km långa objekt, vilka hade valts slumpmässigt, jämnt fördelade över hela landet. I varje objekt på tvåfältsväg mättes de tre delobjekten höger och vänster kantlinje samt mittlinjen.

  • 184.
    Lundkvist, Sven-Olof
    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.
    Yahya, Mohammad Reza
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Tillståndsmätningar av vägmarkeringars funktion år 2012: Trafikverket Region Öst2013Report (Other academic)
    Abstract [sv]

    I föreliggande notat redovisas tillståndsmätningar av vägmarkeringars funktion. Det är en av sex notat som redovisar mätningar i olika delar av landet. Mätningarna har utförts med det mobila systemet Road Marking Tester, vars två centrala komponenter är en reflektometer av typ LTL-M och en optokator för mätning av vägmarkerings makrotextur. Från retroreflexionen och texturen har våta vägmarkeringar skattats på vägar med ÅDT > 4000 fordon. Sammanlagt har mätningar gjorts på 292 cirka 10 km långa objekt, vilka hade valts slumpmässigt, jämnt fördelade över hela landet. I varje objekt på tvåfältsväg mättes de tre delobjekten höger och vänster kantlinje samt mittlinjen.

  • 185.
    Lundkvist, Sven-Olof
    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.
    Fotgängares upptäckbarhet vid olika nivåer på vägbelysningen2011Report (Other academic)
    Abstract [en]

    In Sweden, road lighting is regulated in Vägars och gators utformning (VGU). Generally, the requirement is an average luminance level and a luminance uniformity of the road surface. An important question is if the requirements are reasonable? Too low requirements would mean poor traffic safety and too high levels would mean waste of energy and undesired impact on the environment.

    In night-time traffic, accidents involving vulnerable road users are overrepresented, which may be caused by poor visibility. The aim with the present study was to investigate the influence of the average luminance and the luminance uniformity on the detection distance of pedestrians in road lighting.

    Two pilot studies have been conducted as a full-scale trial on Tagenegatan in Gothenburg. This specific street has a road lighting installation where each light source can be dimmed individually. This means that both the average luminance and the luminance uniformity can be regulated independently. Thus, the effect of the average luminance can be studied at certain levels of uniformity and vice versa. In this experiment the average luminance 1.0, 0.5, 0.35 and 0.0 cd/m2 were studied along with the luminance uniformities 0.0 and 0.4.

    In the first study, five subjects participated, travelling at approximately 50 km/h as passengers in a car. Their only task was to push a silent button when a "pedestrian" was detected. The pedestrian was a grey-painted obstacle, dark grey on one side and light grey on the other and it was located on the right pavement. This meant that the background of the pedestrian partly was the surface of the pavement, partly bushes close behind. The conditions were completely intertwined, which meant that six light conditions were studied, involving four pedestrians; light and dark grey, positioned just behind a light source and between two lanterns, respectively.

  • 186.
    Lundkvist, Sven-Olof
    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.
    Vägbelysningens betydelse för fotgängares synbarhet i mörker2012Report (Other academic)
    Abstract [en]

    The visibility of pedestrians has been measured in a full-scale field experiment. The visibility was quantified by the detection distance to pedestrian who is about to cross a street. Six subjects, sitting as passengers in a Volvo, were used for registering the detection distances. Two pedestrians were standing on the pavement along a street and the subject’s only task was to push a button when they could detect a pedestrian. The test site was located in an industrial area with no or little traffic, and consequently, the measurements could be accomplished without any disturbance from oncoming vehicles. Four illumination conditions were used: 100 % or 65 % of full effect on every light source, 100 % on every second light source, the others switched off, and finally no road lighting at all. In these lighting conditions the average luminance of the road surface turned out to be 1.0; 0.5 and 0.0 cd/m2 with the luminance uniformity 0.4. Furthermore, the luminance uniformity was 0.4 and 0.0 at the average luminance 0.5 cd/m2. The clothing of the pedestrian was either light-grey or black. The pedestrian’s position along the road was either 5 metres behind a light source or half-way between two light sources. Every subject registered every condition two or four times. The independent variables were lighting condition, clothing and position along the road. The only dependent variable was the detection distance.

  • 187.
    Lundkvist, Sven-Olof
    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, Traffic analysis and logistics.
    Tillståndsmätning av vägmarkeringars funktion 20132014Report (Other academic)
    Abstract [en]

    A general conclusion which can be drawn from the condition assessment 2013 is that the performance of road markings in Sweden cannot be approved when having the regulations in mind. Especially, this fact can be observed on high-trafficked roads, which imply that on these roads improved road marking maintenance is needed. During the period 5 May until 23 October 2013, measurement of road marking performance has been carried out in Sweden. A total of 294 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 aim of the condition assessment is primarily to get knowledge of to which extent the road markings fulfil the Swedish regulations. Furthermore, the results can form the basis for future allocation of funds for road marking maintenance; a poor road marking performance in a specific region might indicate that more maintenance is needed. Finally, the performance over years can be studied, as condition assessment has been carried out since 2000 in several counties. The measurements 2013 show that 45 percent of the road marking objects fulfilled the requirements in the Swedish regulations, regarding dry road marking retroreflectivity. The corresponding figure for wet road markings was 19 percent. With respect to dry road markings, Region Nord (North) had the largest part of road marking objects fulfilling the requirements, 73 percent, while only 15 percent were approved in Region Stockholm. In two counties repeated measurements were carried out: a 1st round in May 2013 and a second one in August/September the same year. These measurements showed an increase in retroreflectivity for most road marking objects. This result shows that the time of measurement should be considered when planning the condition assessment.

  • 188.
    Lützhöft, Margareta
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Thorslund, Birgitta
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kircher, Albert
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Gillberg, Mats
    Karolinska institutet.
    Fatigue at sea: a field study in Swedish shipping2007Report (Other academic)
    Abstract [en]

    The purpose of this study was to collect data about the fatigue level of bridge watch keepers to use for revising earlier sleep models, and devise innovative solutions for the shipping industry. Data collection included interviews with shipping companies and a field study onboard 13 cargo vessels. 32 participants took part in representing two watch systems; 2-watch and 3-watch. Subjective sleepiness and stress estimations were performed once every hour. Electrooculography was used to record eye movement behaviour. Reaction time test was made to examine performance. 3-watch participants are more satisfied with their working hours and working situation. Tendencies indicate that 2-watch participants are a bit more tired, whereas the stress is the same. All are less sleepy and less stressed at home. Time on shift had effect on sleepiness. The highest Karolinska Sleepiness Scale scores were recorded in the late night and early morning. After night shift the reaction times have higher variance and more long reaction times are present. The mean value after night shift was significantly higher than after day shift. All thirteen shipping agreed that officers on the bridge always have tasks sensitive to fatigue but no company experienced fatigue as a problem during normal conditions. All were positive to monitoring devices, mentioning safety matters.

  • 189.
    Mårdh, Selina
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction. Linköpings universitet, Psykologi.
    Cognitive erosion and its implications in Alzheimer’s disease2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The aim of the present thesis was twofold, first to map the semantic memory decline in Alzheimer patients over time, second to take the patient’s perspective and create a multifaceted picture of the individual with Alzheimer’s disease through the study of memory, awareness, central coherence and emotions. Further issues concerned how Alzheimer individuals handled their cognitive erosion in everyday life and if they were well calibrated with their spouse in disease related matters.

    Two studies were performed, the first involved a longitudinal study of sematic deterioration, the second had a mixed methods design involving both quantitative and qualitative measures as in neuropsychological assessment and interviews.

    Through the longitudinal study it could be concluded that the nature of semantic deterioration is best described as loss of memory information rather than problems in accessing the information. It was further concluded that semantic concepts gradually lose their specific features during course of illness.

    The results from the second study revealed that the Alzheimer individuals were aware of their disease although they could not foresee the implications of their cognitive shortcomings in their everyday life. They evidenced weak central coherence, in that they were unable to infer details into a meaningful whole. This implies that they perceive their surrounding world in a fragmented way as consisting of separate objects rather than a comprehensible context. Concerning emotions it was found that they responded to negatively valenced words in the same way as normal ageing individuals, although being impaired in their response to positively and neutral words. Finally, the Alzheimer individuals and their spouses were not well calibrated regarding disease related issues.

    The findings of the present thesis have important clinical implications and gives valuable input to the understanding of the individual with Alzheimer’s disease.

    List of papers
    1. A longitudinal study of semantic memory impairment in patients with Alzheimer’s disease
    Open this publication in new window or tab >>A longitudinal study of semantic memory impairment in patients with Alzheimer’s disease
    2013 (English)In: Cortex, ISSN 0010-9452, E-ISSN 1973-8102, Vol. 49, no 2, p. 528-533Article in journal (Refereed) Published
    Abstract [en]

    The present study explored the nature of the semantic deterioration normally displayed in the course of Alzheimer’s disease (AD). The aim was to disentangle the extent to which semantic memory problems in patients with AD are best characterized as loss of semantic knowledge rather than difficulties in accessing semantic knowledge.

    A longitudinal approach was applied. The same semantic tests as well as same items were used across three test occasions a year apart. Twelve Alzheimer patients and 20 matched control subjects, out of a total of 25 cases in each group, remained at the final test occasion.

    Alzheimer patients were impaired in all the semantic tasks as compared to the matched comparison group. A progressing deterioration was evident during the study period. Our findings suggest that semantic impairment is mainly due to loss of information rather than problems in accessing semantic information.

    Place, publisher, year, edition, pages
    Elsevier, 2013
    Keywords
    Cognition, Dementia
    National Category
    Applied Psychology
    Research subject
    SAB, Do Psychology
    Identifiers
    urn:nbn:se:vti:diva-6919 (URN)10.1016/j.cortex.2012.02.004 (DOI)000316926800016 ()22445445 (PubMedID)
    Available from: 2014-06-10 Created: 2014-06-10 Last updated: 2017-12-05Bibliographically approved
    2. Aspects of awareness in patients with Alzheimer's disease
    Open this publication in new window or tab >>Aspects of awareness in patients with Alzheimer's disease
    2013 (English)In: International psychogeriatrics, ISSN 1041-6102, E-ISSN 1741-203X, Vol. 25, no 7, p. 1167-1179Article in journal (Refereed) Published
    Abstract [en]

    Background: The purpose of the present study was to gain insight into Alzheimer's disease (AD) patients' perception of the world through the study of a few aspects of awareness. The aspects in focus of the study were disease awareness, metacognition, managing of everyday life, and as a complement, the agreement (calibration) between patients and their spouses on the studied aspects was considered.

    Method: A mixed-method evaluation design was used involving 15 AD patients, their spouses, and 15 elderly healthy control subjects. The study comprised both a semistructured interview (AD patients and spouse) and a neuropsychological assessment (AD patients and control subjects).

    Results: The patients were aware of their disease and able to report on their illness. Despite this awareness, they were unable to realize and manage the practical and cognitive implications of their impairment. The results also indicate that patients and spouses were not well calibrated regarding thoughts about the disease and problems in handling the cognitive deterioration.

    Conclusions: The findings of our study have relevance to patients' well being and how they manage everyday life. An open dialogue on these issues between spouses and in the care for AD patients would hopefully enhance quality of life for all parties involved.

    Place, publisher, year, edition, pages
    Cambridge University Press, 2013
    Keywords
    Medical aspects, Cognition, Dementia
    National Category
    Medical and Health Sciences
    Research subject
    SAB, V Medicine
    Identifiers
    urn:nbn:se:vti:diva-6918 (URN)10.1017/S1041610212002335 (DOI)000321262200014 ()23425334 (PubMedID)
    Available from: 2013-05-03 Created: 2014-06-10 Last updated: 2017-12-05Bibliographically approved
    3. Weak central coherence in patients with Alzheimer’s disease
    Open this publication in new window or tab >>Weak central coherence in patients with Alzheimer’s disease
    2013 (English)In: Neural Regeneration Research, ISSN 1673-5374, E-ISSN 1876-7958, Vol. 8, no 8, p. 760-766Article in journal (Refereed) Published
    Abstract [en]

    Central coherence refers to the ability to interpret details of information into a whole. To date, the concept of central coherence is mainly used in research of autism, Asperger’s syndrome and recently in the research on eating disorders. The main purpose of the present study was to examine central coherence in patients with Alzheimer’s disease. Nine Alzheimer’s disease patients and ten age- and gender-matched control subjects, who differed significantly in neurological assessment, were shown a picture of a fire. Compared to control subjects, the Alzheimer’s disease patients described the picture in a fragmented way by mentioning details and separate objects without perceiving the context of the fire. In conclusion, patients with Alzheimer’s disease are at the weak end of central coherence, and hence suffer from a fragmented view of their surroundings. The findings have important clinical implications for the understanding of patients with Alzheimer’s diseaseand also for the possibility of caregivers to meet the Alzheimer’s disease individual in an appropriate way in the everyday care.

    Keywords
    Medical aspects, Cognition, Dementia
    National Category
    Medical and Health Sciences
    Research subject
    SAB, V Medicine
    Identifiers
    urn:nbn:se:vti:diva-6917 (URN)10.3969/j.issn.1673-5374.2013.08.011 (DOI)000317029900011 ()
    Available from: 2013-05-03 Created: 2014-06-10 Last updated: 2017-12-05Bibliographically approved
    4. Emotion and recollective experience in Alzheimer’s disease
    Open this publication in new window or tab >>Emotion and recollective experience in Alzheimer’s disease
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Emotional changes are common in Alzheimer’s disease (AD). In addition, damage to brain regions involved in emotion is abundant in AD. Although these finding imply that emotion memory is severely compromised in AD, absolute or relative sparing of emotional memory has occasionally been reported. Hence, we wanted to clarify how well AD patients can remember emotion words. Eighteen AD patients and fifteen healthy older persons participated in the experiment. Participants studied neutral, positive, and negative words. Implicit and explicit memory was assessed in two tasks: a word-fragment completion task and a recognition task, respectively. In the latter task, participants were asked to provide recollective judgments when they indicated that they recognized a word from previous study. Results indicated that AD patients responded to valence, and in particular negative valence, similar to controls, that AD patients evidenced severe deficits as to recollective experience, and that implicit memory remained intact in AD.

    Keywords
    Dementia, Cognition
    National Category
    Medical and Health Sciences
    Research subject
    SAB, V Medicine
    Identifiers
    urn:nbn:se:vti:diva-6916 (URN)
    Available from: 2013-05-03 Created: 2014-06-10 Last updated: 2016-01-20Bibliographically approved
  • 190.
    Mårdh, Selina
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Identifying factors for traffic safety support in older drivers2016In: Transportation Research Part F: Traffic Psychology and Behaviour, ISSN 1369-8478, E-ISSN 1873-5517, Vol. 38, p. 118-126Article in journal (Refereed)
    Abstract [en]

    The present study aimed at identifying factors for traffic safety support in older drivers. This was achieved by studying the co-operation between older drivers and their ordinary front seat passenger (co-driver). The knowledge emerging from such study can enhance the understanding of what kind of support an older driver needs and also help facilitate proper design of in-vehicle support systems and intervention training programs for older drivers. A within group field study was carried out, using a mixed-methods evaluation design. Four elderly couples participated in the study. The drivers included in the study requested and received on-going directional support, traffic -and driving strategic help, help with look-out and reminding of current speed limit. It was evident from comparisons between interview data and field data that how the participants themselves described their need of support differed from what support they requested (drivers) and gave (co-drivers) in real driving. Furthermore, data revealed that three out of four drivers were given a score of 2 in the Useful Field Of View test (UFOV). It was evident that there are areas in which older drivers need and request support. The results from the present study could be used in the design process, and in evaluation of, in-vehicle support systems as well as in developing intervention training programs customised for older drivers.

  • 191.
    Mårdh, Selina
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Nägga, Katarina
    Clinical Memory Research, Lund University, Sweden.
    Samuelsson, Stefan
    Linköpings universitet, Pedagogik och didaktik.
    A longitudinal study of semantic memory impairment in patients with Alzheimer’s disease2013In: Cortex, ISSN 0010-9452, E-ISSN 1973-8102, Vol. 49, no 2, p. 528-533Article in journal (Refereed)
    Abstract [en]

    The present study explored the nature of the semantic deterioration normally displayed in the course of Alzheimer’s disease (AD). The aim was to disentangle the extent to which semantic memory problems in patients with AD are best characterized as loss of semantic knowledge rather than difficulties in accessing semantic knowledge.

    A longitudinal approach was applied. The same semantic tests as well as same items were used across three test occasions a year apart. Twelve Alzheimer patients and 20 matched control subjects, out of a total of 25 cases in each group, remained at the final test occasion.

    Alzheimer patients were impaired in all the semantic tasks as compared to the matched comparison group. A progressing deterioration was evident during the study period. Our findings suggest that semantic impairment is mainly due to loss of information rather than problems in accessing semantic information.

  • 192.
    Nilsson, Josef
    et al.
    SP Tech. Res. Inst. of Sweden.
    Strand, Niklas
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Falcone, Paolo
    SAFER - Fordons- och Trafiksäkerhetscentrum.
    Vinter, Jonny
    Driver performance in the presence of adaptive cruise control related failures: implications for safety analysis and fault tolerance2013In: Conference on Dependable Systems and Networks Workshop (DSN-W) 2013: 43rd Annual IEEE/IFIP, IEEE Press, 2013, , p. 9p. 1-10Conference paper (Refereed)
    Abstract [en]

    This study explored how failures related to an adaptive cruise control (ACC) were handled by drivers and what the effects on safety can be. The experimental study included forty-eight subjects and was performed in a moving base driving simulator equipped with an ACC. Each subject experienced two different failures in separate scenarios. In total, the study included four different failures, i.e., Unwanted acceleration, Complete lack of deceleration, Partial lack of deceleration, and Speed limit violation. The outcome of each failure scenario has been categorized based on whether the driver managed to avoid a collision or not. For the outcomes where collisions were successfully avoided, the situations were analyzed in more detail and classified according to the strategy used by the driver. Besides showing that partial lack of deceleration caused more collisions than complete lack of deceleration (43% compared to 14% of the participants colliding), the results also indicate a preference among drivers to steer and change lane rather than to apply the brakes when faced with acceleration and deceleration failures. A trade off relationship was identified between allowing a failing ACC to stay operational and on the other hand disabling it when an error is detected. Keeping the system operational can cause confusion about the mode of the system but as the results of the study indicate it can also improve the situation by reducing impact speed.

  • 193.
    Nygårdhs, Sara
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Literature review on variable message signs (VMS) 2006-20092011Report (Other academic)
    Abstract [en]

    VMS can be used in a number of ways, for instance for information about speed, travel time, roadworks ahead, congestion, accidents, lane shift, weather, route guidance and events. During 2006-2009 a large number of studies regarding VMS have been completed, of which 61 are referred to in this report. Suggested areas of future research include graphic messages on VMS, legibility of VMS and information units.

  • 194.
    Nygårdhs, Sara
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Samspel mellan vägbelysning och vägbeläggning med avseende på energiförbrukning2011Report (Other academic)
    Abstract [en]

    The aim of the project "Interaction between road lighting and road surface for reduced energy consumption", financed by the Swedish Energy Agency, was to study if it is possible to reduce road lighting and thereby save energy and money by using brighter pavements than those normally used. The study has been performed in two steps: Step 1 aimed to estimate costs for transporting stone material, maintenance and energy for road lighting, both when using conventional stone materials and brighter materials. In step 2, road surfaces in some Swedish municipalities have been audited by field measurements of the luminance coefficient of road surfaces. Under the premise that the road lighting construction has been dimensioned according to the existing regulations, the aim of this audit was to investigate if the actual road surface brightness would mean an over- or underestimation of the illuminance in the road lighting

    construction.

  • 195.
    Nygårdhs, Sara
    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.
    Field test on visibility at cycle crossings at night2010In: European Transport Research Review, ISSN 1867-0717, E-ISSN 1866-8887, Vol. 2, no 3, p. 139-145Article in journal (Refereed)
    Abstract [en]

    Purpose: The main purpose of the study was to compare the night-time visibility distance of cycle crossings to the nighttime visibility distance of bicyclists at the corresponding cycle crossings. This was tested both for dry and wet road surface. Methods: The test was carried out as a field study with twelve participants being passengers in an instrumented car. The test route included nine cycle crossings, that all were combined with pedestrian crossings. The participants individually pushed a noiseless button when they saw a dummy bicyclist standing still at a crossing, in part one, and when they saw a correctly marked cycle crossing in part two. Visibility: distances to bicyclist dummies and cycle crossings were measured. Half of the participants experienced dry road surface and the other half wet road surface. An analysis of variance was conducted with a split plot design of group (wet / dry road surface) × target (bicyclist dummy / cycle crossing) × crossing (9 different cycle crossings). Results: The bicyclist dummies were detected at a significantly longer distance (mean 59.1 m, standard error 2.9 m) than the cycle crossings (mean 17.5 m, standard error 1.0 m). The road condition (wet/dry) only had an effect on the visibility of cycle crossings. Conclusion: The field test showed that bicyclists are seen at longer distances than cycle crossings combined with pedestrian crossings in Sweden at night-time.

  • 196.
    Nygårdhs, Sara
    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, Lars
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Nilsson, Lena
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Field test on visibility at cycle crossings at night2010Report (Other academic)
    Abstract [en]

    This report describes a field study which is part of the project "Road user support in night-time traffic". The first steps in the project were a literature review on night-time traffic in urban areas and a focus group study where road users' needs and experiences of night-time traffic in urban areas were discussed. The aim of the field study was to compare the night-time visibility distance of cycle crossings to the night-time visibility distance of bicyclists at the corresponding cycle crossings. This was tested both for dry and wet road surface. Twelve volunteers participated in the study; six at dry road surface and six at wet road surface conditions. They sat as passengers in an instrumented car at night travelling along a test route including a total of 19 cycle crossings. The participants indicated when they noticed bicyclists (stationary dummies) and cycle crossings along the test route, and the visibility distance was registered and stored.

  • 197.
    Nygårdhs, Sara
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Herrstedt, Lene
    Trafitec.
    Sörensen, Kai
    DELTA Light & Optics.
    Readability of variable message traffic sign2010Report (Other academic)
    Abstract [sv]

    This report describes a number of tests of the readability of variable message traffic signs that were carried out in a period from the spring of 2008 until the autumn of 2009. An even earlier test is not mentioned. A variable message traffic sign is called VMS in the following. The tests are described approximately in the sequence they were carried out. To some degree the sequence describes a "learning by doing" process in which later tests were based on earlier tests. All the tests involve presentation of a number of prearranged messages on a VMS, representing variation of some parameters supposedly related to the readability of the messages, to a group of test persons. In the early tests, the criterion for the readability was the reading distance of each of the messages for each of the test persons. In the later tests the criterion was rating of the readability at predetermined distances.

  • 198.
    Nygårdhs, Sara
    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.
    Tillståndsmätning av vägmarkeringars funktion år 2009 i SMN, SST och SSÖ2010Report (Other academic)
    Abstract [en]

    Starting in 2000, condition assessment of road markings have been carried out in Sweden. As previously, the purpose of the study has been to answer the questions: - To which degree is the performance in the Swedish regulations fulfilled? - Is there any difference in road marking quality within the same region, i.e. between the counties? - How has the performance fluctuated over time?

    The retroreflectivity and macro texture of dry road markings have been measured using the RMT version 2 in 2009. The retroreflectivity of wet road markings and the skid resistance have been estimated from the dry performance and the macro texture.

  • 199.
    Nygårdhs, Sara
    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.
    Tillståndsmätning av vägmarkeringars funktion år 2010 i SST, SÖ, SSY och SM2011Report (Other academic)
    Abstract [sv]

    Starting in 2000, mobile condition assessment of dry road marking retroreflectivity has been carried out in Sweden. Later, also the retroreflectivity of wet road markings has been estimated from the dry performance and the macro texture. As in 2009, this estimation is made for profiled markings on European highways (excluding lane lines). This year, 2010, the length of the measurement objects has been reduced from 20 km to 10 km with the aim of measuring more objects. This year also involved the transition of the Swedish National Road Administration into the Swedish Transport Administration (April 1st 2010), and a change of the administrative regions.

    As in previous years, there are several motives with condition assessments: - To which degree is the performance in the Swedish regulations fulfilled? - Is there any difference in road marking quality within the same region, i.e. between the counties? - How has the performance fluctuated over time?.

  • 200.
    Nygårdhs, Sara
    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.
    Andersson, Jan
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Dahlbäck, Nils
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    The effect of different delineator post configurations on driver speed in night-time traffic: A driving simulator study2014In: Accident Analysis and Prevention, ISSN 0001-4575, E-ISSN 1879-2057, Vol. 72, p. 341-350Article in journal (Refereed)
    Abstract [en]

    The aim of the study was to investigate how different delineator post configurations affect driver speed in night-time traffic. In addition, the potential speed effect of introducing a secondary task was investigated. The study was carried out in a car simulator on a road stretch including straight road sections as well as curves with different radii. Fourteen drivers participated in the study and the results show that absence of delineator posts leads to reduced speed. However, provided that there are delineator posts continuously present along the road, the overall driver speed is basically the same, regardless of the spacing between the delineator posts. The results also imply that to reduce driver speed in curves with small radius, using more compact spacing of posts in these curves as compared to in curves with a larger radius, could be a potential strategy. Additionally, the speed reducing effect of a secondary task was only prevailing where the task was initiated.

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