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Törnros, Jan
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Publications (10 of 69) Show all publications
Falkmer, T., Nilsson, L. & Törnros, J. (2012). Detection and identification of information presented peripherally inside the car: effects of driving task demands and stimulus position. In: Gale, Alastair G. (Ed.), Vision in vehicles - IX: . Paper presented at The 9th International Conference on Vision in Vehicles, held in Brisbane, August 2001, Australia (pp. 189-196). Loughborough: Loughborough University. Applied Vision Research Centre
Open this publication in new window or tab >>Detection and identification of information presented peripherally inside the car: effects of driving task demands and stimulus position
2012 (English)In: Vision in vehicles - IX / [ed] Gale, Alastair G., Loughborough: Loughborough University. Applied Vision Research Centre , 2012, p. 189-196Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Loughborough: Loughborough University. Applied Vision Research Centre, 2012
Series
Vision in vehicles ; IX
Keywords
Driver assistance system, Visual display, Field of vision, Driver, Mental load, Simulator (driving), Test, Förarstödssystem, Bildskärmar, Synfält, Förare, Mental belastning, Körsimulatorer, Test
National Category
Applied Psychology
Research subject
80 Road: Traffic safety and accidents, 841 Road: Road user behaviour; 90 Road: Vehicles and vehicle technology, 911 Road: Components of the vehicle; 90 Road: Vehicles and vehicle technology, 914 Road: ITS och vehicle technology
Identifiers
urn:nbn:se:vti:diva-5320 (URN)978-0-9571266-1-9 (ISBN)
Conference
The 9th International Conference on Vision in Vehicles, held in Brisbane, August 2001, Australia
Available from: 2013-12-03 Created: 2013-12-03 Last updated: 2014-10-01Bibliographically approved
Törnros, J. (2007). Läkemedel i trafiken: förekomst och effekter på trafikolyckor och körprestation. Linköping: VTI., VTI rapport 590
Open this publication in new window or tab >>Läkemedel i trafiken: förekomst och effekter på trafikolyckor och körprestation
2007 (Swedish)Report (Other academic)
Alternative title[en]
Medicinal drugs - prevalence and effects on traffic accidents and driving performance
Abstract [sv]

A survey was performed on literature on medicinal drugs and traffic safety, mainly published 1991 or later. Results from epidemiological and experimental studies were covered. Epidemiological studies are of different types. Drug prevalence is studied in drivers suspected of driving under the influence of alcohol or drugs or in drivers injured in traffic accidents. Studies of drug prevalence in the general driving population are less common. These studies do not permit calculations of accident risks. The second type of epidemiological studies is accident analysis studies, where accident risks are calculated for different drugs. These studies can be divided into case-control studies, responsibility studies and pharmaco-epidemiological studies. Because of a number of methodological problems in these studies, the results must be interpreted with caution. The experimental studies are limited to those performed in real car driving or in driving simulators.

Place, publisher, year, edition, pages
Linköping: VTI., VTI rapport 590, 2007. p. 96
Series
VTI rapport, ISSN 0347-6030
Keywords
Drugs, Medication, Driving aptitude, Danger, Accident, Risk, In situ, Test, Laboratory, Simulator
Research subject
Road: Traffic safety and accidents, Road: Alcohol and drugs
Identifiers
urn:nbn:se:vti:diva-6445 (URN)
Available from: 2013-12-03 Created: 2013-12-03 Last updated: 2013-12-03
Östlund, J., Nilsson, L., Törnros, J. & Forsman, Å. (2006). Effects of cognitive and visual load in real and simulated driving. Linköping: Statens väg- och transportforskningsinstitut
Open this publication in new window or tab >>Effects of cognitive and visual load in real and simulated driving
2006 (English)Report (Other academic)
Abstract [sv]

A simulator and a field experiment were conducted to study the effects of visual and cognitive load on driving performance, and also to assess the validity on the VTI simulator as a tool for studying the effects of distraction. It was found that visual load resulted in deteriorated lateral control and to some extent reduced speed control, although there was a clear effect of the drivers reducing their speed and increasing the steering activity in order to compensate for the increased visual load. Cognitive load resulted in somewhat reduced speed control, but more clearly, increased steering activity and more stable lane keeping. This increase in lateral control was interpreted as the drivers in precaution creating a larger safety margin in case of an unexpected event, which they were assumed to be less capable to react to due to the cognitive load. The simulator validity was found to be very high, except from that less realistic risk in the simulator seemed to result in less level of stress and higher travel speed in the simulator.

Place, publisher, year, edition, pages
Linköping: Statens väg- och transportforskningsinstitut, 2006. p. 82
Series
VTI rapport, ISSN 0347-6030 ; 533A
Keywords
Driver, Behaviour, In vehicle information, Mental load, Cognition, Attention, Vision, Steering, Speed, Reaction time, Simulator, Test, In situ
National Category
Psychology
Research subject
Road: Traffic safety and accidents, Road: Road user behaviour; Road: Traffic engineering, Road: ITS och traffic
Identifiers
urn:nbn:se:vti:diva-6398 (URN)
Available from: 2013-12-03 Created: 2013-12-03 Last updated: 2016-02-25Bibliographically approved
Helmers, G. & Törnros, J. (2006). Effekt av övergångskurvor på förares säkerhetsmarginal samt inverkan av träning: ett försök i körsimulator. Linköping: VTI., VTI rapport 501
Open this publication in new window or tab >>Effekt av övergångskurvor på förares säkerhetsmarginal samt inverkan av träning: ett försök i körsimulator
2006 (Swedish)Report (Other academic)
Alternative title[en]
Effect of transition curves on drivers' safety margin and the influence of training - an experiment in a driving simulator
Abstract [sv]

Sharp curves constitute a significant safety risk. The question is if it is possible to design sharp curves in such a way that drivers pass them with greater safety margins? In this work we studied the effect of transition curves (in the form of clothoides) added to the constant radius curve segment on drivers´ choice of speed and maximal lateral acceleration. The study was carried out in VTI´s driving simulator II. Influence on the results of the subjects´ experience and training in driving the simulator was studied by repetition of the first experimental session for all subjects on each of the following two working days. The results showed, firstly, that the drivers chose higher speeds in curves with clothoides, secondly, that there was no difference in maximal lateral acceleration, and finally, that these results were not influenced by training.

Place, publisher, year, edition, pages
Linköping: VTI., VTI rapport 501, 2006. p. 38
Series
VTI rapport, ISSN 0347-6030
Keywords
Driver, Behaviour, Transition curve, Curve, Degree of curvature, Speed, Acceleration, Simulator, Test
Research subject
Road: Traffic safety and accidents, Road: Road user behaviour; Road: Traffic safety and accidents, Road: Geometric design and traffic safety
Identifiers
urn:nbn:se:vti:diva-6393 (URN)
Available from: 2013-12-03 Created: 2013-12-03 Last updated: 2013-12-03
Törnros, J., Dahlstedt, S. & Helmers, G. (2006). Spontant hastighetsval i olika trafikmiljöer i tätort. Linköping: VTI., VTI notat 9-2006
Open this publication in new window or tab >>Spontant hastighetsval i olika trafikmiljöer i tätort
2006 (Swedish)Report (Other academic)
Abstract [sv]

Car drivers' spontaneous speed choice in urban areas was studied and compared with posted speed limits. Two groups of middle-aged men, experienced car drivers, participated in the study. One group consisted of thirteen drivers with at least five years experience of car driving in Linköping. The other group consisted of eight drivers with very little experience of car driving in Linköping. The participants drove a pre-determined test route in the city of Linköping four times with covered speedometer. The total driving distance was 96 km. The participants were alone in the car during driving. Route guidance was given during the drive, both verbally and visually. The location and timing of the guidance were controlled by a GPS-based computer. Before the test drive the participants were instructed to drive as they normally do without stress. The participants' speed (75th percentile) for each of the route sections and for each of the four drives was measured and analysed. After completion of the test the participants rated some of the route sections. The measured speed varied substantially between route sections (traffic environments). However, the agreement between measured speeds across route sections was large between as well as within individuals. Along some route sections the speed was higher, and along others it was lower, than the posted speed limit. The speed variation across traffic environments (route sections) can to a large extent be explained by the variation between the traffic environments and to a much less extent by the variation between participants.

Place, publisher, year, edition, pages
Linköping: VTI., VTI notat 9-2006, 2006. p. 82
Series
VTI notat
Keywords
Speed, Choice, Driver, Behaviour, Urban area, Man, Speed limit
Research subject
Road: Traffic safety and accidents, Road: Road user behaviour
Identifiers
urn:nbn:se:vti:diva-1594 (URN)
Available from: 2013-12-03 Created: 2013-12-03 Last updated: 2013-12-03
Helmers, G. & Törnros, J. (2004). Effekt på hastighet och sidoacceleration av läget hos rotationscentrum för snäva kurvors skevning samt inverkan av träning: ett försök i körsimulator. Linköping: Statens väg- och transportforskningsinstitut., VTI meddelande 967
Open this publication in new window or tab >>Effekt på hastighet och sidoacceleration av läget hos rotationscentrum för snäva kurvors skevning samt inverkan av träning: ett försök i körsimulator
2004 (Swedish)Report (Other academic)
Alternative title[en]
Effects on vehicle speed and side acceleration related to the location of the centre of rotation for banking of sharp curves, and influence of training : An experiment in a driving simulator
Abstract [sv]

Sharp curves constitute a significant safety risk. The question is if it is

possible to design sharp curves in such a way that drivers pass them with

greater safety margins? In this work we studied if the drivers´ choice of

speed and side acceleration will change with the location of the centre of

rotation for banking of sharp curves. Influence of training was studied by

repetition of the first experimental session during each of the following

three working days for all subjects. The study was carried out in VTI´s

driving simulator (Model I). The results show firstly, that the location of

the centre of rotation for banking of sharp curves influenced the drivers´

choice of speed and side acceleration and secondly, that these results were

not influenced by training.

Place, publisher, year, edition, pages
Linköping: Statens väg- och transportforskningsinstitut., VTI meddelande 967, 2004
Series
VTI meddelande, ISSN 0347-6049
Keywords
Swedish, Sweden, Simulator, Driver, Behaviour, Bend, Degree of curvature, Acceleration, Side, Rotation, Speed, Driver training
Research subject
Road: Traffic safety and accidents, Road: Road user behaviour; Road: Highway design, Road: Geometric design
Identifiers
urn:nbn:se:vti:diva-5148 (URN)
Available from: 2013-12-03 Created: 2013-12-03 Last updated: 2013-12-03
Kircher, A., Vogel, K., Törnros, J., Bolling, A., Nilsson, L., Patten, C., . . . Ceci, R. (2004). Mobile telephone simulator study. Linköping: Statens väg- och transportforskningsinstitut., VTI meddelande 969A
Open this publication in new window or tab >>Mobile telephone simulator study
Show others...
2004 (English)Report (Other academic)
Abstract [sv]

The study consists of four separate experiments conducted in the VTI driving

simulator. The common theme was to investigate how driver behaviour and

traffic safety are influenced when the driver attends to another technical

device while driving. The experiments were concerned with handsfree or

handheld mobile phone conversation and dialling, receiving mobile phone SMS

messages and watching a DVD film (the latter two being minor pilot

experiments). In three of the experiments (mobile phone conversation, SMS,

DVD) the participants drove a route which led through urban and rural

environments, ranging from 90 km/h rural to 50 km/h urban environments. The

urban environments differed in complexity (three levels). The driving

distance was about 70 km. The dialling experiment used a rural environment

with a speed limit of 110 km/h. The driving distance was about 15 km. In the

main experiment dealing with mobile phone conversation, a number of driving

performance measures were analysed: driving speed, variation in lateral

position, deceleration, brake reaction time, headway, time to collision, etc.

PDT (Peripheral Detection Task) was used as a measure of mental workload.

Mobile phone conversation was found demanding in terms of mental workload. It

also had effects on driving. Most effects were quite similar for the two

phone modes (handsfree, handheld). Impaired reaction time performance was

demonstrated in one of the situations for handheld mode. However, effects

were found which could be interpreted as attempts to compensate for the

increased workload caused by the mobile phone conversation: speed was reduced

(more so for handheld than for handsfree mode), and time and distance headway

increased. In spite of these compensatory behaviours, mental workload was

still markedly increased by phone use. In the SMS experiment the participants

braked later in one situation when reading the SMS message. No other effects

were found in this minor experiment. In the DVD experiment, mental workload

increased when watching the film, although this was compensated for to some

extent by the increased distance headway to a lead vehicle. No compensation

in terms of reduced driving speed, however, was apparent in this experiment.

In the dialling experiment negative effects on traffic safety were evident

from the larger variance of lateral car position during the dialling task for

the handsfree phone mode. The mental workload also increased with the

dialling task. Compensation in terms of reduced driving speed was apparent

for both phone modes. Other aspects of mobile phone use while driving still

remain to be analysed in more detail, such as starting or finishing a call,

looking for a phone number to dial, mishaps like dropping the phone, etc.

Place, publisher, year, edition, pages
Linköping: Statens väg- och transportforskningsinstitut., VTI meddelande 969A, 2004
Series
VTI meddelande, ISSN 0347-6049
Keywords
English, Sweden, Mobile, Telephone, Driving, Simulator, Driver, Behaviour, Attention, Driving aptitude, Stress, Safety
Research subject
Road: Traffic safety and accidents, Road: Road user behaviour
Identifiers
urn:nbn:se:vti:diva-5151 (URN)
Available from: 2013-12-03 Created: 2013-12-03 Last updated: 2020-01-23
Törnros, J. & Wallman, C.-G. (2003). Inverkan av spår i beläggningen på förarbeteendet: en förstudie i VTI:s körsimulator. Linköping: Statens väg- och transportforskningsinstitut
Open this publication in new window or tab >>Inverkan av spår i beläggningen på förarbeteendet: en förstudie i VTI:s körsimulator
2003 (Swedish)Report (Other academic)
Alternative title[en]
Influence of pavement ruts on driver behaviour : a pilot study in the VTI driving simulator
Abstract [sv]

Syftet med denna förstudie var tvåfaldigt. För det första gällde det att undersöka om VTI:s körsimulator med sina begränsningar är lämpad för denna typ av studier. Om detta är fallet, kan de komma att bli ett hjälpmedel för Vägverket att bedöma de sammantagna effekterna av olika vägytetillstånd.

Det andra syftet var att beskriva i vilken utsträckning vägytans tillstånd påverkar förarnas körbeteende.

Förstudien begränsades till att omfatta studium av körbeteendet på spåriga vägar, där spåren låg i nivå med den omgivande vägytan, men där buller och vibrationer ökade påtagligt.

Simulatorstudien visar små men ofta signifikanta skillnader i såväl körbeteende som subjektivt bedömda effekter.

Ingen skillnad i genomsnittlig hastighet kan konstateras, däremot är hastighetsvariationen större vid spårig väg.

Beträffande sidoläge, så skiljer sig inte de genomsnittliga värdena i nämnvärd grad mellan spårig och slät vägyta. Man tycks försöka undvika att köra i spåren, på den jämna vägen körde man längre sträcka med ett sidoläge som motsvarar spårläget.

Varken för självrapporterad arbetsbelastning eller för självrapporterad ansträngning föreligger någon signifikant skillnad mellan spårig och jämn väg. Däremot visade sig skattningen av hur besvärlig man ansåg körningen vara ge signifikanta skillnader i bedömningen: spårig väg ansågs generellt vara besvärligare.

Abstract [en]

The aim with the pilot study was twofold. Firstly, to examine if the VTI driving simulator with its restraints is suited for this kind of studies. Secondly, to describe to what extent the condition of the road surface influence the driver behaviour.

The study was confined to studying driver behaviour on rutted roads, where the ruts were on a level with the surrounding road surface, but where noise and vibrations increased obviously.

The study shows small but often significant differences in driving behaviour as well as subjectively assessed effects.

No difference in mean speed can be established; however, the speed variance is greater for the rutted road.

The mean values of lateral position differ very little between rutted and smooth road; however, subjects tended to avoid driving in the ruts. On the smooth road they drove a long stretch with a lateral position corresponding to the position of the ruts.

Neither for self-reported work load nor for self-reported effort is there any significant difference between rutted or smooth road. The assessment of how difficult the driving task was, however, showed significant differences: rutted road was generally considered as more difficult.  

Place, publisher, year, edition, pages
Linköping: Statens väg- och transportforskningsinstitut, 2003
Series
VTI meddelande, ISSN 0347-6049 ; 940
Keywords
Swedish, Sweden, Rutting, Driver, Behaviour, Simulator, Method, Speed, Side, Pavement, Vehicle handling
Research subject
80 Road: Traffic safety and accidents, 841 Road: Road user behaviour; 30 Road: Highway design, 33 Road: Surfacing
Identifiers
urn:nbn:se:vti:diva-5041 (URN)
Available from: 2013-12-03 Created: 2013-12-03 Last updated: 2017-03-22Bibliographically approved
Falkmer, T., Nilsson, L. & Törnros, J. (2000). Detection and identification of information presented peripherally inside the car: effects of driving task demands, stimulus position and direction of motion of the stimulus. Linköping: Statens väg- och transportforskningsinstitut
Open this publication in new window or tab >>Detection and identification of information presented peripherally inside the car: effects of driving task demands, stimulus position and direction of motion of the stimulus
2000 (English)Report (Other academic)
Alternative title[sv]
Inhämtande av rörlig visuell information presenterad perifert i bilen : effekter på uppmärksamhetsfördelning och körprestation i varierad trafikmiljö
Abstract [en]

The aim was to study the performance of an in-car information system relying exclusively on information presented peripherally by “running light” stimuli. The information was presented on displays placed in four different positions; upper, lower, to the right, and to the left. Four different directions of the “running light” were used; upwards, downwards, to the right, and to the left. Two levels regarding driving task demands were used.

Thirty-two subjects participated in the study. A repeated-measures design was used. The study was performed in an advanced driving simulator. The subjects’ task was to report the direction of motion of the peripheral stimuli as quickly as possible.

A traffic situation with high demands on the driver caused the subjects to fixate the peripheral stimulus to a lesser extent than when the driving task was less demanding. The upper display was fixated to a smaller extent than the left or the right one. However, differences in number of fixations between the displays appeared only when the demands of the driving task were high, not when they were low. No effects of the direction of motion of the stimulus on the number of fixations appeared.

There were very few errors regarding the identification of the direction of the stimulus, regardless of whether the stimulus was fixated or not.

The response times were short. There were differences between display positions. The response time was shortest for the right display and for the lower display, but somewhat longer for the other two displays. It was somewhat shorter when the stimulus was fixated than when it was not. Driving task demands had no effect on response time. Regarding effects of the direction of motion of the stimulus, there was only a very weak interaction with driving task demands and display position.

Abstract [sv]

Syftet var att studera funktionen hos ett informationssystem som enbart använder sig av visuell information, presenterad perifert i synfältet med hjälp av ”rinnande ljus” i bilen. Informationen presenterades på displayer i fyra olika positioner; upptill, nedtill, till höger och till vänster. Fyra olika riktningar hos det “rinnande ljuset” användes; uppåt, nedåt, åt höger, och åt vänster. Två nivåer beträffande kravet hos köruppgiften användes.

Trettiotvå försökspersoner deltog i studien. Designen var upprepad mätning. Studien genomfördes med hjälp av en avancerad körsimulator. Försökspersonernas uppgift var att så snabbt som möjligt rapportera rörelseriktningen hos de perifera stimuli som presenterades.

En krävande köruppgift fick försökspersonerna att fixera perifert stimulus i mindre utsträckning än då köruppgiften var mindre krävande. Den övre displayen fixerades i mindre utsträckning än den vänstra och högra. Skillnader mellan displayer beträffande antal fixationer förelåg dock endast för den krävande köruppgiften, ej vid den mindre krävande. Däremot erhölls ingen effekt av stimulus’ rörelseriktning på antalet fixationer.

Mycket få fel registrerades beträffande identifieringen av stimulus’ rörelseriktning oavsett om stimulus fixerades eller ej.

Svarstiderna var genomgående korta. Det förelåg en skillnad mellan displaypositioner. Svarstiden var kortast för den högra och för den nedre displayen, men något längre för den övre och den vänstra displayen. Den var något längre då stimulus fixerades än när detta ej var fallet. Ingen effekt av de skilda kraven hos köruppgiften förelåg beträffande svarstider. Vad gäller effekter av stimulus’ rörelseriktning förelåg endast en mycket svag interaktion med köruppgiftens krav och displayposition.

Place, publisher, year, edition, pages
Linköping: Statens väg- och transportforskningsinstitut, 2000. p. 28
Series
VTI rapport, ISSN 0347-6030 ; 461A
Keywords
English, Sweden, Driver information, In vehicle information, Peripheral vision, Detection, Attention, Direction, Stimulus, Visual display, Driving simulator
Research subject
90 Road: Vehicles and vehicle technology, 914 Road: ITS och vehicle technology; 80 Road: Traffic safety and accidents, 841 Road: Road user behaviour
Identifiers
urn:nbn:se:vti:diva-1756 (URN)
Available from: 2013-12-03 Created: 2013-12-03 Last updated: 2017-02-09Bibliographically approved
Törnros, J. (2000). Effects of tunnel wall pattern on simulated driving behaviour. Linköping: Statens väg- och transportforskningsinstitut., VTI EC research 9
Open this publication in new window or tab >>Effects of tunnel wall pattern on simulated driving behaviour
2000 (English)Report (Other academic)
Place, publisher, year, edition, pages
Linköping: Statens väg- och transportforskningsinstitut., VTI EC research 9, 2000
Series
VTI EC research: reprint of European Commission Research Documentation, ISSN 1403-4905
Keywords
English, Sweden, Tunnel lining, Design, Driver, Behaviour, Human factor, Simulator, Speed, Posture, Retardation
Research subject
Road: Traffic safety and accidents, Road: Road user behaviour; Road: Highway design, Road: Tunnels
Identifiers
urn:nbn:se:vti:diva-4461 (URN)
Available from: 2013-12-03 Created: 2013-12-03 Last updated: 2013-12-03
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