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It is obvious that those who live near a road like to be involved during the planning phase of a road reconstruction. The Swedish Transport Administration would most likely benefit from making residents more involved in the planning process and from providing clear information about the road safety potential of the implemented measures. A better understanding of the measures’ potential contribution to increase safety is likely to give a greater acceptance.

The aim of this study performed by VTI was to learn more about what residents, commuters and truck drivers think of the measures taken along two Swedish country roads.

Concerning one of the roads the truck drivers were positive to the reconstruction even though their fears concerning lack of respect for the continuous centerline had come true. They were also negative regarding the short distance of the gradient field. They would have appreciated if it had been longer. In addition, they argued for deeper milled rumble strips in order to make vibration and sound more easily felt in heavy vehicles. As it is now the truck drivers hardly notice the rumble strips when passing them with a truck.

Even though the roads previously had had a high traffic density with many dangerous overtakings and a lot of accidents with wild animals, there was little understanding of the reasons behind the reconstructions. The acceptance for fences to protect from wild animals was high, but the other measures implemented to improve road safety were more difficult to substantiate.

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People in the transport system

  • Published: 2012-04-27
  • VTI-code: N18-2012

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The objective of the project was to propose a harmonised method for monitoring the proportion of pedestrian and cycle traffic, which enables comparisons to be made over years and between towns, regions or the country as a whole. The intention is that the method should be mainly used for evaluations at an overriding level, for example for determining whether measures to promote increased pedestrian and cycle traffic have had the desired effect. The point of departure of the project has been that it is important for both modes, walking and cycling, to be monitored separately. The project has focused on local monitoring in Swedish municipalities of a certain size – at least 25,000 inhabitants, and the methods taken into consideration are travel surveys and cycle flow measurements.

The evaluation of the preliminary method through municipal tests and analyses, and subsequent discussions, has resulted in some practical recommendations to local authorities concerning the way the proportion of pedestrian and cycle traffic should be monitored in order to enable comparisons to be made over time and between places. The basic units recommended are the proportion, represented by cycle traffic, of all trips which have their starting point and destination in the municipality on weekdays. Journeys in which cycling is combined with public transport are also to be reported, but separately. For the local authorities which perform a more detailed travel survey, with e.g. advanced geographical coding, the report also contains proposals for more detailed units of measurement.

With regard to cycle counts, we have drawn the conclusion that, with the resources that are reasonable at present, it is not possible, with the help of cycle counts, to reliably estimate the change from one year to another. Cycle counts can, on the other hand, be used for identifying trends in a longer term and for the planning and monitoring of specific measures on individual routes. A random selection of measuring sites should make it possible to estimate the cycle mileage in a municipality and, in the long run, also the change in cycle mileage, but this requires more preparatory work and may involve some practical problems. In addition, a large selection of measuring sites is needed for reliable estimates of change.

The proposed harmonised method is aimed at monitoring pedestrian traffic and cycle traffic so that trends over time may be identified and comparisons made with other places and on a national level. However, the proposal of a harmonised method is not enough; it is also essential that it should really be applied in municipal monitoring. In order that the aim of comparable proportions should be achieved, it is necessary that the Swedish Transport Administration, or a similar player with an overriding national responsibility, should devise incentives that motivate municipalities to apply the harmonised method.

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Research area

People in the transport system
Transport system

  • Published: 2012-03-23
  • VTI-code: R743

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In order to achieve the interim target for road safety it is necessary that compliance of speed limits increases at the road network. VTI has been commissioned by the Swedish Transport Administration to analyse major problems and challenges concerning velocity, and to identify key areas for action.

Through a review of available knowledge about speed, and gain of new knowledge from focus group discussions we found that different types of incentives are needed for both private motorists and professional drivers to hold the speed.

Both education and information are important to motivate the driver to act correctly and create a norm in society that deprecates speed violations. However, this should occur in combination with speed monitoring and technical measures.

We found that both the understanding of speed limits and the awareness of the dangers of high speeds are inadequate. This may be due to that serious accidents very rarely occur in an individual’s surroundings. Therefore people do not calculate this risk. However, there is awareness of that one should respect the lower speed limits in areas where vulnerable road users are. This awareness may be possible to use when measures are implemented. High speeds are positive for a lot of people: better mobility, high enjoyment and more comfortable driving better suited to other traffic. Many drivers also have difficulty in seeing the connection between road design and speed limit, despite the comprehensive review of speed limits which has been undertaken by the Swedish Transport Administration.

It is clear that additional incentives are required to achieve greater compliance with speed limits. The individual must win something to keep the speed limits. It could be about making financial gain by saving money on fuel consumption or lower insurance costs. Avoiding fines can also be seen as an economic gain. For fines to have effect a real risk of detection is required. On roads with speed cameras there is an awareness of detection risk. However, today speed cameras in Sweden are not a measure that influences the motorcyclists.

Concerning heavy traffic, our analysis shows that it should be possible to achieve improvements by imposing more stringent requirements in procurements, by introducing different types of certifications and instruments as well as having systematic follow-ups and controls. It is also important that schedules and timetables the drivers have to comply with, do not presuppose that the speed limits have to be exceeded. This is also linked with the rules of driving- and rest times and the ability to take breaks. Here it is important to consider if the current actions can be improved or if it is possible to find new ways of working.

Technical solutions such as ISA (Intelligent Speed Adaption) are an opportunity to achieve better compliance with speed limits, but financial incentives may be required for introduction on a larger scale.

Environmental awareness in the society is growing and through this it is important to get the message across about how speed affects fuel consumption and carbon emissions.

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Research area

People in the transport system
Traffic safety

  • Published: 2012-02-22
  • VTI-code: N6-2012

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open

Camera-based sleepiness detection

Year:
2012
VTI-code:
ViP 2011-6

Authors: Katja Kircher , Carina Fors , Christer Ahlström , Anna Anund , Per Sörner , Jordanka Kovaceva , Emanuel Hasselberg , Martin Krantz , John-Fredrik Grönvall

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

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

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

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

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

The final set of indicators were an estimated KSS value that was based on the value the driver reported before the driving session (KSSestSR), standard deviation of lateral position (SDLP) and fraction of blinks > 0.15 s (fracBlinks, for EOG based and 1-camera-based). An optimal threshold for discriminating between KSS above and below 8 was determined for each indicator. The performances were in the range of 0.68–0.76.

Two decision trees based on the selected indicators were created: one using the fracBlinksEOG and one using fracBlinks1CAM. The performances of the two trees were 0.82 and 0.83 respectively (on the training dataset), i.e., the overall performance of the EOG based and the 1-camera-based classifier were similar, although individual differences could be seen. The performance decreased to 0.66 when using a validation dataset from another study, which illustrates the difficulties in creating a generalized sleepiness classifier.

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Research area

People in the transport system

  • Published: 2012-02-15
  • VTI-code: ViP 2011-6

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The starting point for this study is to gain deeper understanding of how older women and men use public transport, but also to enhance the understanding of whether they are using other means of transport and what the basis for their choices is. The study’s interest is in the variations and patterns in their narratives.

To make it possible for older people to live an active life with good quality high demands should be met for the transport system, e.g. availability and safety. If not, there will be a large number of people at risk of not coming out. Because the elderly are a heterogeneous group, a single type of transport does not fit all. Previous studies show that men and women generally travel in different ways during their working life. The present report is a study of how retired women’s and men’s experience of public transport is related to other transport modes.

The aim of this study is to examine how older people describe their decisions to travel, and how they experience their everyday transports. To grasp the heterogeneity among older people the subjects involved were recruited from both urban and rural areas. They have different backgrounds, age and gender. The majority of them are ethnic Swedish people. However, the study also included people with different ethnic background.

The study includes 30 qualitative interviews with older people. 18 women and 12 men aged 58–94 years were interviewed. Fifteen interviewees also wrote travel diary for two weeks. The analysis of the study is based on the interviewees’ stories (narratives).

Salient in the results of this study is how differently the interviewees describe their daily lives and what opportunities they have to transport themselves. Above all they describe the desires and needs that are perceived. Mobility barriers are noticeable in the inter¬viewees’ stories, but also strategies they have developed to make their everyday travel work.
The respondents often transported themselves by walking, sometimes even by bicycle; actually many chose walking or bicycling before bus or car. They stressed the import¬ance of coming out and meeting other people, and moving around in different environments. They even referred to the importance of health reasons.

Elements of restrictions appear in some of their stories which are not always by their own choice and must therefore be considered in future planning so that these individuals are not left out of the contexts they need and want to participate in. Examples of restric¬tions might be long distance to the bus stop, stairs, travel centers and other interchanges at different levels/floors, timetables that are not synchronized or buses at times that do not fit older people’s daily activity patterns. Except from deficiencies in public transport, it can also be about cycle paths or sidewalks that abruptly end at a difference in level, or stairs to the next available accessible area. When the whole chain of move¬ments in the transport environment is not available, problems may occur. For the oldest respondents, it is particularly important that the 'whole journey' works.

It is more common that the younger respondents travel by car and the interviewees also refer to car driving as an activity when one is reasonably young and healthy. But a lot of them are still driving at the age of 80–90, some even after the 90th birthday, which indicate that it is not until you can no longer drive a car as you become more dependent on society's resources and of other people. Decreased independence, this implies, occurs later and later in life, which clearly shows the problem of discussing older people's mobility on the basis of chronological age. The habits, capacities and abilities are incredibly varied among the elderly.

The women in the present study describe the bus in more positive terms than men. Many of those who want to travel by bus believe that the bus is a good means of transport and describe it in certain ways: efficient, safe, environmentally friendly and economically efficient. More women than men in the study also describe that they are happy to choose other means of travel in instead of the car in order to be able to relax, watch and meet other people, but also to have some time for themselves.

The results also show that very old people sometimes opt out of a trip "with the right of age." One can, after having carried out one or two longer trips during a week choose not to travel because it is tiring. Choosing a day at home, or to opt out of a planned activity or invitation, should not be seen as negative per se, however, it is important to note that the need for service and social interaction do not necessarily decrease at old age.

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Research area

People in the transport system

  • Published: 2011-12-22
  • VTI-code: R734

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There exist small tendencies which point in the direction of enhanced traffic safety problems with the introduction of extra-long trucks. The purpose of a recent VTI study has been to investigate if the introduction of extra-long and heavy vehicles has an effect on traffic safety on Swedish roads, especially in relation to overtaking.

In the study, traffic safety effects have been measured in terms of road user behavior concerning speed and accelerations and time slots. Road user experiences and heavy truck drivers’ experiences have also been studied. The traffic conflict technique presents how time-to-collision and speed are related to accidents and near accidents. The traffic conflict technique has been used as a starting point for the discussion on how the introduction of extra-long trucks might affect traffic safety.
The report presents four empirical studies: a focus group interview study with heavy truck drivers, an interview study with drivers of extralong trucks, a simulator study and a field study. The simulator study and the field study focus on overtaking.

The purpose with the focus group interview is to investigate if the heavy truck drivers (that do not drive the extra-long trucks) have an opinion on how extra-long vehicles might have an impact on traffic safety. The purpose with the interviews of drivers of extra-long trucks is to grasp the experiences they have of the extra-long trucks. Truck drivers that do not drive extra-long trucks believe that the introduction of extra-long trucks will create a number of traffic safety problems especially in terms of conflicts with ordinary road users. The drivers of extra-long trucks do not experience the problems that ordinary truck drivers predict. The problems they experience can be taken care of with more planning (thinking ahead). They also believe that the traffic sign on the back of the extra-long vehicle has a positive effect. The truck company, working environment and truck equipment are other important aspects mentioned by the drivers of the extra-long vehicles.

The simulator study investigates overtaking situations on a 2+1-road, with extra-long trucks (30 m) and an ordinary truck (18.75 m). The results reveal that the distance from the back of the truck to the point where only one lane exists affects car drivers’ decision to overtake, independently of truck length. If the back of the truck is in the same position, the time slot for a safe overtaking was reduced significantly for extra-long trucks compared to ordinary trucks. Overtaking speed was, however, the same (approxi¬mately 117 km/h).

The field study also studies overtaking situations with an extra-long vehicle (30 m) (with a license to drive on a specific road) and a reference vehicle (24 m), on a 2+1 road and an ordinary 2 lane road. Overtaking vehicles were video recorded with the purpose to measure overtaking behaviour but also in order to be able to contact the road users by telephone. The overtaking personal car drivers did not experience a traffic safety conflict on the road at hand. They did not even remember overtaking an extra-long vehicle. The number of data points was relatively few, especially for the reference vehicle. No significant differences were obtained for overtaking speed or time slots. The overtaking speed was, however, relatively high for both trucks. On the other hand video analyses revealed a small overrepresentation of critical time slots for critical overtakings of the extra-long truck on a normal road, but not for the 2+1 road.

The conclusion is that there exist small tendencies which point in the direction of enhanced traffic safety problems with the introduction of extra-long trucks. The results should, however, not be overinterpreted since the number of data point was few and collected in specific situations and in specific conditions. A conclusion is also that more research is needed. Not to be forgotten is the reduction of the number of trucks on the road if extra-long trucks will be permitted.

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Research area

People in the transport system
Traffic safety

  • Published: 2011-12-09
  • VTI-code: R732

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Speed and braking behaviour of drivers do hardly differ between daylight and night when they are to turn right over a cycle path. However, their gaze behaviour differs in daylight and night. Measurements done at VTI show that drivers tend to look at the cycle path more in daylight as well as that they look more at approaching cyclists in daylight. The head-mounted eye tracking system used in the VTI measurements worked well.

Previous studies have indicated that the risk of cyclists being involved in an accident increases at night, and that the visibility at cycle crossings is poor. The aim of the present study was to evaluate a method for assessment of drivers’ gaze behaviour and to study gaze and driving behaviour at cycle crossings after turning to the right.

Twenty-one drivers participated in the study. The participants were equipped with a head-mounted eye tracking system and were then instructed to drive along a predetermined test route in the town of Linköping, both in daylight and at night. Five cycle crossings after right turns were passed. At the last cycle crossing during the second and last driving session, a cyclist was approaching the crossing. After each driving session, the participants filled in a questionnaire about their experiences of cycle crossings, too.

Gaze behaviour just before and at the cycle crossings was analysed. The participants tended to look towards the cycle path more in daylight than at night. When a cyclist was approaching the crossing, the participants looked at her earlier in daylight than at night. The differences in speed and braking distance between daylight and at night were small.

The majority of the participants thought, to some extent, that the visibility at cycle crossings needs to be improved. The most preferred measures to be taken were intense street lighting, road signs (with or without flashing lights), reflective material on posts and reflective raised pavement markers.

Using a head-mounted eye tracking system worked well for analysis of driver gaze behaviour towards well-defined objects. The system worked as well in daylight as at night. A disadvantage is that the system reduces the drivers’ abilitiy to turn their head.

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Research area

People in the transport system

  • Published: 2011-12-08
  • VTI-code: R733A

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It is difficult to say how dangerous it is for drivers to talk or text while they are driving since it depends on the situational context and the driver's capabilities. Recent studies indicate that the occurrence of crashes, near-crashes and safety critical events is correlated with handling the telephone (dialing, texting), but not with just talking on a mobile phone. This does not mean, however, that talking on the phone while driving is safe in all situations and for all drivers. It is more likely to be at least in part a sign that drivers have capabilities to self-regulate their telephoning behaviour.

Mobile phone conversation increases reaction times and inattention. In addition, texting and dialing require the driver to look at the device and away from the road, leading to reduced vehicle control and increased driver inattention.

Most drivers think that they are more suited than the average on handling their mobile phone whilst driving. A majority also believes that it is safer to use a hands-free phone than a handheld, even though there are many studies that suggest that hands-free usage is no better than handheld.

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Research area

People in the transport system
Traffic safety

  • Published: 2011-11-21
  • VTI-code: R729A_R729

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The prevalence of illicit drugs and medicines in the driving population, i.e. among drivers on the road, was 2.5 per cent between the years 2006 and 2011 in Sweden. The prevalence of alcohol, illicit drugs and medicines among drivers killed in traffic the same years was 31.2 per cent.
In comparison with other countries in the EU project DRUID, Sweden has the highest proportion of negative results, i.e. drivers without the presence of alcohol, drugs or medicine. This applies to both drivers on the road and drivers killed in traffic .

The studies that form the basis of this report have been performed within the project DRUID – Driving under the influence of drugs, alcohol and medicine, which is a project within the EU's Sixth Framework Programme, which lasted five years (2006–2011). This report presents two sub-studies from the DRUID project. The aims of these studies were:
• to study the prevalence of illicit drugs and medicines in the driving population (study among drivers on the road)
• to study the prevalence of alcohol, illicit drugs and medicines among killed drivers (study of killed drivers).
In the study among drivers on the road, saliva samples were collected. Toxicological results were analysed from 6,199 drivers in Södermanland, Örebro and Östergötland out of 10,223 drivers of passenger cars and vans that were stopped by the police in March 2008– February 2009. In the study of killed drivers we have toxicological results from 157 fatalities out of 178 drivers of passenger cars and vans that were killed in traffic accidents in 2008.
The analysis included a total of 29 drugs, medicines and metabolites. The study among killed drivers also included alcohol.
In the study among drivers on the road 97.5 per cent were negative for all substances. Alcohol was not included in the study because only drivers with a negative breath test participated. Illicit drugs occurred in 0.4 per cent of the drivers and medicinal drugs occurred in 2.1 per cent. A combination of illicit and medicinal drugs was found in 0.02 per cent of the drivers. The most common illicit drugs among drivers on the road were amphetamines and THC (cannabis) which occurred in 0.2 per cent of the drivers respectively. Opiates and opioids were the most common drug with a prevalence of 1.1 per cent. Z-drugs occurred in 0.5 per cent and benzodiazepines in 0.3 per cent of the drivers on the road. When results are broken down into age and gender groups it can be found that the overall prevalence was higher in women and older drivers, depending on a higher prevalence of medicinal drugs. These results should be interpreted with caution because they are very uncertain.
In the study of killed drivers 68.8 per cent were tested negative for all substances. Alcohol occurred in 19.5 per cent of the drivers, of which 3.5 per cent were in combina¬tion with illicit drugs and/or medicinal drugs. Illicit drugs occurred in 3.5 per cent of killed drivers and medicinal drugs in 6.3 per cent. In 2.1 per cent of the killed drivers a combination of illicit and medicinal drugs were found. Amphetamines were the most commonly used illicit drug with a prevalence of 2.8 per cent. Z-drugs occurred in 2.1 per cent of the killed drivers. Combinations of drugs from more than one group occurred in 2.8 per cent, however, no combination of illicit drugs from more than one group was found. Because of the small number of killed drivers, it is difficult to draw any conclusions about subgroups. However, the results show a higher prevalence among male drivers than among female drivers, both in terms of alcohol and drugs among killed drivers.

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Research area

People in the transport system

  • Published: 2011-09-30
  • VTI-code: N23-2011

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A workshop initiated by the Traffic Education Group (TUG) at VTI on the theme “Traffic Education - What research is currently conducted in the field today and how do we want the field to develop" was held at VTI in November 2010. TUG was represented by six researchers and six visiting participants from The National Society for Road Safety (NTF), The Swedish National Association of Driving Schools (STR), Trivector Information and The Swedish Transport Agency participated. Initially a lecture was held on the topic of educational trends of today. The presentation focused on the relationships between learning goals, teaching methods and examination. The presentation was followed by a discussion presented in this report.
A lot of research has been conducted in the field but has it been put into practice? Various methods have been tested but not yet used on a larger scale. A proposal about traffic education in the mandatory school has been developed but as the subject will not be compulsory it will probably have very low practical impact. Another important question is who is responsible for financing research in this field. It seems like this task has fallen through the cracks.

The largest part of the discussion was devoted to driving license education and the question was raised whether or not there would be a revision of the whole system initiated by the politicians. The evaluation results of the new syllabus for driving license B indicate that little has changed within the driving license education and the question is whether the driving teachers need more support to transform the curriculum into practical education. The driving schools have to contend with a culture where as few lessons as possible is considered the best (cost and time), which makes it difficult to improve teaching quality.

What research is conducted today and what should be focused on in the future? Formal teaching at driving schools (both theory and practice) has not been scientifically proved to be more efficient than informal private driver training with laymen instructors. Driver instructor's role as interpreter of the course objectives and to translate these into teaching was highlighted as a research area to focus on. The new driver instructor education (with permit and supervising by the new authority Yh-myndigheten, the Swedish National Agency for Higher Vocational Education) was discussed and whether the content and quality of education were deprioritized in relation to the teacher's employability.

Furthermore, there was request for more research on young (mainly male) learner drivers’ brain development (higher order cognitive skills) and the impact of this on their development into safe car drivers (risk perception and self-assessment). What are the motives behind of either a wish to get a license or to refrain from driving was an issue considered valuable to explore further. The importance of the dissemination of research results to teachers and students was also emphasized. Collaboration between branch organizations (and other stake holders) and researchers was consider another important subject.

In Sweden, researchers in traffic education were considered to be few and the need to collaborate and form a network in order to develop traffic education research emerged during the meeting. A number of research questions to explore further were proposed and VTI's coordinating role was highlighted.

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Research area

People in the transport system
Traffic safety

  • Published: 2011-09-13
  • VTI-code: N11-2011

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