| 1. |
- Radun, Igor, et al.
(författare)
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Company employees as experimental participants in traffic safety research : Prevalence and implications
- 2019
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Ingår i: Transportation Research Part F. - Stockholm : Elsevier BV. - 1369-8478 .- 1873-5517. ; 60, s. 81-92
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Tidskriftsartikel (refereegranskat)abstract
- The use of company employees as experimental participants when testing products, technology or paradigms developed by the same company raises questions about bias in results and research ethics. We aimed to investigate the prevalence of studies authored by car company researchers with car company employees as participants, to assess the risk of bias in such studies, to investigate journal editors’ opinions in the field of traffic safety regarding these procedures, and to offer a general discussion about ethical and methodological implications. Three types of data were collected. We (i) examined guidelines and recommendations for authors in eleven selected peer-reviewed journals in the area of traffic safety; (ii) surveyed editors of these journals; and (iii) reviewed articles authored by researchers from a selected group of car manufacturers and published in these journals during 2011–2015. Guidelines and recommendations for authors in the included journals did not mention whether and under what circumstances company employees can be research participants, nor did publishers’ general guidelines. However, three out of the four editors who responded to our survey believed that this issue of private company researchers using participants from the same company deserves to be explicitly addressed in their journal’s guide for authors. The total number of regular articles and conference papers during 2011–2015 in the eleven journals reviewed was 6763; 95 (1.4%) listed at least one car manufacturer in the authors’ affiliations; and out of these, nine included company employees as participants. In summary, company employees are seldom (0.13%) used as research participants in traffic safety research. Nevertheless, the use of company employees as research participants raises questions about bias in results as well as about incursions into the participants’ autonomy.
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| 2. |
- Berg, Hans-Yngve, et al.
(författare)
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Learner drivers and lay instruction : how socio-economic standing and lifestyle are reflected in driving practice from the age of 16
- 1999
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Ingår i: Transportation Research Part F: Traffic Psychology and Behaviour. - 1369-8478. ; 2:3, s. 167-179
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Tidskriftsartikel (refereegranskat)abstract
- On September 1st 1993, a new law came into effect in Sweden, permitting instructor-supported driving practice from the age of 16 instead of 17 years and 6 months. The intention was to enable young people to gain more experience of driving a car before they acquire a driver's permit and thereby to reduce their accident risk. The study was conducted by means of a questionnaire posted to 601 17-year-olds throughout Sweden. The participants were analysed concerning gender, socio-economic standing (blue-collar and white-collar), and lifestyle (friend-oriented, externally-oriented and parent-oriented). The results show that men obtain a learner's permit more often than women (67.4% vs 57.2%) and that youngsters in white-collar families acquire a learner's permit in more cases than those in blue-collar families (67.4% vs 52.4%). One of the reasons for the latter group not acquiring a permit is that they cannot afford it, while children in white-collar families state that they have neither the time nor the desire. No significant difference was found between the three lifestyle groups. When it comes to the amount of practice, the men have been out on the road on average 39.9 h during their first 13 months, compared to 19.9 h for the women. In the lifestyle groups, those who belong to the so-called externally-oriented lifestyle have practised most. They have reported 39.2 h compared to the parent-oriented group with the least amount of training, 27.9 h on average. The friend-oriented group has 22.2 h of practice. When both lifestyle and socio-economic standing were considered, even greater differences were found. The white-collar group of the externally-oriented lifestyle reported as much as 51.5 h, compared to the blue-collar group of the parent-oriented lifestyle with only 18.4 h of practising. The above result is important because it is not in accordance with the intentions of the new driving practice system. The idea behind the new system was that all young people should have the opportunity for a longer period of driving practice in order to reduce the high accident risk during the first year with a driver’s license. If it is impossible for certain groups of youngsters to start their driving practice at the age of 16, the situation will become socially unjust and measures must be taken to remedy this situation.
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| 3. |
- Falkmer, Torbjörn, et al.
(författare)
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Fixation patterns of learner drivers with and without cerebral palsy (CP) when driving in real traffic environments
- 2001
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Ingår i: Transportation Research Part F. - 1369-8478 .- 1873-5517. ; 4:3, s. 171-185
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Tidskriftsartikel (refereegranskat)abstract
- Among learner drivers with cerebral palsy (CP), driver education is problematic for those failing to fulfil their education as well as for those becoming licensed drivers. A crucial ingredient in the development of driving is the quality of the visual search. Problems increase for CP learners in those parts of training where high demands are set on visual search abilities. The aim of the study was to increase knowledge about search patterns among learners with CP in comparison with learners and experienced drivers without CP. The study was carried out in traffic by measuring eye movements and the duration and distribution of fixation. The results show that search strategies among learners with CP were less flexible than in the control groups. The results suggest a need for better methods for teaching CP learners search strategies and may provide a tool for such development. © 2001 Elsevier Science Ltd.
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| 4. |
- Garvill, Jörgen, et al.
(författare)
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Factors influencing drivers' decision to install an electronic speed checker in the car
- 2003
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Ingår i: Transportation Research Part F: Traffic Psychology and Behaviour. - 1369-8478. ; 6:1, s. 37-43
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Tidskriftsartikel (refereegranskat)abstract
- Intelligent speed adaptation (ISA) refers to various concepts aiming at limiting the vehicle speed. In Umea, Sweden, a large scale field study was carried out to test the possibility to, on a voluntary basis, install one type of ISA device in private vehicles. In this study 10,300 car owners were contacted by telephone and offered to have an ISA device installed in their car. This paper reports on drivers' attitudes to four different ISA-applications and on factors influencing the decision to install the one type of ISA, an electronic speed checker (ESC). The results show that approximately 40% of the respondents accepted the offer to have an ESC installed in their vehicle. The analysis indicated that age, perceived risk, moral and perceived difficulty to keep the speed limits significantly influenced their evaluation of the ESC and that the perception of the ESC influenced the decision to participate.
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| 5. |
- Hakamies-Blomqvist, L., et al.
(författare)
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Driver ageing does not cause higher accident rates per km
- 2002
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Ingår i: Transportation Research Part F. - 1369-8478 .- 1873-5517. ; 5:4, s. 271-274
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Tidskriftsartikel (refereegranskat)abstract
- Based on Finnish survey data, older (65+, n=1559) and younger (26-40, n=310) drivers' accident rates were compared. In accordance with earlier studies, the rates were similar per driver (0.1) but there was a non-significant trend towards older drivers having more accidents per distance driven (10.8 vs. 8.3 per 1 million km). However, when the accidents-per-km comparison was made in groups matched for yearly exposure, there is no evidence for higher risk with increasing age. In both age groups, risk per km decreased with increasing yearly driving distance. We suggest that the previous perception of an age-related risk increase of accidents per distance driven arises from a failure to control for low mileage bias at all ages. © 2003 Elsevier Science Ltd. All rights reserved.
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| 6. |
- Hatakka, Mika, et al.
(författare)
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From control of the vehicle to personal self-control, broadening the perspectives to driver education
- 2002
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Ingår i: Transportation Research Part F. - 1369-8478 .- 1873-5517. ; 5:3, s. 201-215
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The objective is to formulate guidelines and goals for future development in the area of driver training and education. The content of this paper is not empirical, but merely an analytical summary or review. A four-level descriptive model is presented in which driver behaviour is conceptualised as a hierarchy, in which the goals and motives of the driver play an essential role. The recent constructivist ideas in mainstream pedagogy and psychology of learning are combined with a hierarchical approach to driver behaviour. A comprehensive framework for goals and contents of driver education (GDE framework) is presented. Two main conclusions can be drawn. Firstly, the conceptual analysis points towards a need to emphasise the motivational aspects in driver education more than it is done at present. Secondly, in order to reach the goals, pedagogical methods should be re-evaluated. For example, active learning methods and use of self-reflection should be promoted in driver education.
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| 7. |
- Lundberg, C., et al.
(författare)
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Driving tests with older patients : Effect of unfamiliar versus familiar vehicle
- 2003
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Ingår i: Transportation Research Part F. - 1369-8478 .- 1873-5517. ; 6:3, s. 163-173
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the study was to study the effect, for older license holders, of taking a driving test with an unfamiliar vehicle, as compared to their own cars. The study population consisted of licensed patients 65-85 years referred to the Traffic Medicine Centre (TrMC), Huddinge University Hospital, for an evaluation of their medical and cognitive fitness to drive. In the clinical practice of TrMC, driving tests have been used since 1997, with inspectors from the Swedish National Road Administration (SNRA) acting as evaluators. Initially, patients were allowed to use their own cars. From the beginning of the year 2000, however, dual brakes were made mandatory and most evaluations were then made with SNRA cars. When comparing the outcomes of driving tests from the period prior to 2000 (n=96) and after 2000 (n=69), it was found that the number of drivers who failed the test increased by 16%. Also, those who passed the test after more than one trial decreased by 20%. The potential of the neuropsychological assessment to correctly classify drivers in outcome groups was considerably reduced in the period after 2000. These results support the view that, for older drivers with cognitive deterioration, the need to adapt to an unfamiliar vehicle represents a supplementary cognitive load that may compromise their driving ability and the validity of the assessment. A measure aimed only at increasing the safety of examiners and examinees thus had an unintended side-effect that is detrimental to older clinical populations. © 2003 Elsevier Ltd. All rights reserved.
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| 8. |
- Rimmo, P.-A., et al.
(författare)
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Older drivers' aberrant driving behaviour, impaired activity, and health as reasons for self-imposed driving limitations
- 2002
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Ingår i: Transportation Research Part F. - 1369-8478 .- 1873-5517. ; 5:1, s. 345-360
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Tidskriftsartikel (refereegranskat)abstract
- The present study used a mail survey addressed to Swedish drivers aged between 55 and 92 years (n = 939) to study the relationship between driving exposure, health, and four types of self-reported aberrant driving behaviour as measured with a Swedish version of the driver behaviour questionnaire. Age and gender were the most important predictors of the tendency to sometimes avoid driving. However, even after accounting for age and gender, reports of own erroneous driving behaviour because of inattention (e.g., failure to notice a signal) and inexperience errors (viz., handling the car), as well as impaired health, were related to self-imposed driving limitations, whereas the violations and mistakes factors were not. Problems with activities of daily living were only marginally associated with self-imposed driving limitations, mediated through inattention and inexperience errors. The results support the notion that older drivers adjust their driving in response to their health and to the problems they experience while driving. © 2002 Elsevier Science Ltd. All rights reserved.
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| 9. |
- Vogel, Katja
(författare)
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What characterizes a free vehicle in an urban area?
- 2002
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Ingår i: Transportation Research Part F. - 1369-8478 .- 1873-5517. ; 5:1, s. 313-327
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Tidskriftsartikel (refereegranskat)abstract
- The concept "free vehicle" is used widely in the transportation research literature, but as yet there is no common standard for a definition. In this article a standard is provided that is based on the assumption that a vehicle can be considered free, when its speed is not influenced by the speed of the vehicle traveling ahead. In order to determine empirically a threshold for free vehicles in urban areas, speed, distance headway, and time headway data of more than 100 000 vehicles were analyzed. Analyses showed that the speeds of two vehicles are linearly dependent on time headway for headways up to 6 s. It is important to distinguish between this value and the drivers' preferred headway, which is in the region of 2 s
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| 10. |
- Abenoza, Roberto, et al.
(författare)
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Determinants of traveler satisfaction : Evidence for non-linear and asymmetric effects
- 2019
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Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 66, s. 339-356
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Tidskriftsartikel (refereegranskat)abstract
- Classifying public transport service attributes based on their influence on overall traveler satisfaction can assist stakeholders and practitioners in introducing cost-efficient measures. To date most studies employed methods that were based on the assumption that the impact of service attributes on traveler satisfaction is entirely linear and symmetric. This study examines whether service attributes have a non-linear and asymmetric influence on the overall travel experience by employing the Three-factor theory (basic, performance and exciting factors). The analysis is conducted for different traveler segments depending on their level of captivity, travel frequency by public transport and travel mode used, and is based on a relatively large sample size collected for Stockholm County. Moreover, the estimated models control for important socio-demographic and travel characteristics that have been insofar overlooked. Results are presented in the form of a series of multi-level cubes that represent different essentiality of traveler needs which provide a useful methodological framework to further design quality service improvements that can be applied to various geographical contexts. Our findings highlight that a “one size fits all” approach is not adequate for identifying the needs of distinct traveler segments and of travelers using different travel modes. Furthermore, two-thirds of the attributes are consistently classified into the same factor category which entails important policy implications. This research deepens and expands the very limited knowledge of the application of the three-factor theory in the transport field.
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| 11. |
- Adell, Emeli, et al.
(författare)
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Auditory and haptic systems for in-car speed management – A comparative real life study
- 2008
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Ingår i: Transportation Research. Part F: Traffic Psychology and Behaviour. - : Elsevier BV. - 1369-8478. ; 11:6, s. 445-458
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Tidskriftsartikel (refereegranskat)abstract
- Field experiments with ISA (intelligent speed adaptation) were carried out in Hungary and Spain in 2003 and 2004, respectively. Twenty private vehicles in each country were equipped with two kinds of systems: (1) support via an active accelerator pedal (AAP) and (2) warning via beep signals and a flashing red light when the speed limit was exceeded (BEEP). The test drivers drove for a month with both systems installed in each car. Speed was continually logged in all the vehicles and the test drivers were interviewed about their acceptance and experiences of the systems. The results show that both systems reduced the mean and 85 percentile speeds, but that the AAP was more effective. There was no long-lasting effect on speeds when the systems were removed. After the trial half of the drivers were willing to keep an ISA system, but more drivers wanted to keep the BEEP-system even though it showed lower satisfaction ratings than the AAP. The results indicate no major differences between the countries despite the workload being perceived to be higher in Hungary than in Spain.
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| 12. |
- Adell, Emeli, et al.
(författare)
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Driver comprehension and acceptance of the active accelerator pedal after long-term use
- 2008
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Ingår i: Transportation Research. Part F: Traffic Psychology and Behaviour. - : Elsevier BV. - 1369-8478. ; 11:1, s. 37-51
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Tidskriftsartikel (refereegranskat)abstract
- Driver comprehension and acceptance of the active accelerator pedal (AAP) after long-term use were evaluated in a large-scale Swedish trial held in 2000-2002. The system was installed in the cars of 281 test drivers who then used it for between six months and a year. The participants' responses, elicited by questionnaires in the end of the trial, showed a positive rating of the concept of the AAP, while the willingness to pay for it was lower than for other driver-assistance systems studied elsewhere. The typically skeptical driver was a young, male, company car driver with initially negative attitude and a faulty AAP. The typically enthusiastic driver was an older, female, private driver with initially positive attitude and a fault-free AAP. The drivers found that the system, if not satisfactory, was useful but added to the emotional pressure felt by the driver. However, they did think it had positive impacts on performance and safety. Still, the largest perceived effect was a decrease in the risk of being fined for speeding. The gap between the concept of the AAP and willingness to keep and pay for the system puts a clear focus on the importance to define acceptance and developing a tool to ensure reliable assessments of it.
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| 13. |
- af Wåhlberg, Anders, 1965-
(författare)
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Changes in Driver Celeration Behavior over Time : do Drivers Learn from Collisions?
- 2012
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Ingår i: Transportation Research Part F. - : Elsevier BV. - 1369-8478 .- 1873-5517. ; 15:5, s. 471-479
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Tidskriftsartikel (refereegranskat)abstract
- Although it is well known that drivers’ accident risk changes with experience, it has never been specified exactly how this comes about in terms of changes of behaviour, or what features of their experiences are important for this change. One possibility is that drivers learn from their collision involvement, and change their behaviour after such events, as some studies indicate. However, relative accident involvement tends to be very stable over time, which indicates the opposite. Repeated measurements of celeration (speed change) behaviour of bus drivers were compared between two groups; drivers without accidents within the measurement period (about 3 years), and drivers with at least one crash. For the crash group, there was a steady decline in their celeration values over time, but this was not related to their crashes. A similar reduction was also present for the non-crash sample. The results would seem to be in agreement with the theory of accident proneness; there exist stability in driver behaviour over time, despite accident involvement. However, this stability is relative within the sample, and not absolute. The reduction in celeration values for both groups over time would seem to indicate that drivers learn from their experiences in general, but not specifically from accidents. The present study seems to indicate that daily experience of driving situations is the strongest factor for changes in driving behaviour.
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| 14. |
- af Wåhlberg, Anders, 1965-
(författare)
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Re-education of young driving offenders : Effects on recorded offences and self-reported collisions
- 2011
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Ingår i: Transportation Research Part F. - : Elsevier BV. - 1369-8478 .- 1873-5517. ; 14:4, s. 291-299
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Tidskriftsartikel (refereegranskat)abstract
- New ways of educating offending drivers are being introduced, notably e-learning. This type of education has rarely been tested for its safety effects before. An e-learning course for offending young drivers was therefore evaluated as to its effects upon offence and self-reported collision rates. Significant reductions in number of offences and penalty points were found for an e-learning group, while this was not the case for drivers who had been fined only, or had taken a more traditional solely class-room based educational scheme. The e-learners also reported a larger reduction in collision involvement than a random control group, although a regression to the mean effect could not be ruled out. The results seem to indicate a positive effect of the e-learning course for young driving offenders. This conclusion, however, is to be interpreted in relation to the weak association between penalty points and collisions, and the low validity of self-reported collision involvement data. The present results lend further support to the use of e-learning driver improvement courses, although the most important type of data, recorded collisions, is still missing.
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| 15. |
- af Wåhlberg, Anders, 1965-, et al.
(författare)
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The effect of social desirability on self reported and recorded road traffic accidents
- 2010
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Ingår i: Transportation Research Part F. - : Elsevier BV. - 1369-8478 .- 1873-5517. ; 13:2, s. 106-114
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Tidskriftsartikel (refereegranskat)abstract
- The use of lie scales has a fairly long history in psychometrics, with the intention of identifying and correcting for socially desirable answers. This represents one type of common method variance (bias introduced when both predictors and predicted variables are gathered from the same source), which may lead to spurious associations in self-reports. Within traffic safety research, where self-report methods are used abundantly, it is uncommon to control for social desirability artifacts, or reporting associations between lie scales, crashes and driver behaviour scales. In the present study, it was shown that self-reports of traffic accidents were negatively associated with a lie scale for driving, while recorded ones were not, as could be expected if the scale was valid and a self-report bias existed. We conclude that whenever self-reported crashes are used as an outcome variable and predicted by other self-report measures, a lie scale should be included and used for correcting the associations. However, the only existing lie scale for traffic safety is not likely to catch all socially desirable responding, because traffic safety may not be desirable for all demographic groups. New lie scales should be developed specifically for driver behaviour questionnaires, to counter potential bias and artifactual results. Alternatively, the use of a single source of data should be discontinued.
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| 16. |
- Ahlström, Christer, et al.
(författare)
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Bicyclists’ visual strategies when conducting self-paced vs. system-paced smartphone tasks in traffic
- 2015
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Ingår i: Transportation Research Part F. - : Elsevier BV. - 1369-8478 .- 1873-5517. ; 41, s. 204-216
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Tidskriftsartikel (refereegranskat)abstract
- Visual distraction among cyclists interacting with their mobile phones is a growing concern. Yet, very little research has actually investigated how cyclists apply visual strategies and adapt task execution depending on the traffic situation. The aim of this study is to investigate visual behaviour of cyclists when conducting self-paced (initiated by the cyclist) vs. system-paced (initiated by somebody else) smartphone tasks in traffic. Twenty-two cyclists completed a track in real traffic while listening to music, receiving and making calls, receiving and sending text messages, and searching for information on the internet. The route and the types of tasks were controlled, but the cyclists could choose rather freely when and where along the route to carry out the tasks, thus providing semi-naturalistic data on compensatory behaviour. The results show that the baseline and music conditions were similar in terms of visual behaviour. When interacting with the phone, it was found that glances towards the phone mostly came at the expense of glances towards traffic irrelevant gaze targets and also led to shortened glance durations to traffic relevant gaze targets, while maintaining the number of glances. This indicates that visual “spare capacity” is used for the execution of the telephone tasks. The task type influenced the overall task duration and the overall glance intensity towards the phone, but not the mean nor maximum duration of individual glances. Task pacing was the factor that influenced visual behaviour the most, with longer mean and maximum glance durations for self-paced tasks. In conclusion, the cyclists used visual strategies to integrate the handling of mobile phones into their cycling behaviour. Glances directed towards the phone did not lead to traffic relevant gaze targets being missed. In system-paced scenarios, the cyclists checked the traffic more frequently and intensively than in self-paced tasks. This leads to the assumption that cyclists prepare for self-initiated tasks by for example choosing a suitable location. Future research should investigate whether these strategies also exists amongst drivers and other road user groups.
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| 17. |
- Alger, Susanne, 1967-, et al.
(författare)
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Agreement of driving examiners' assessments : evaluating the reliability of the Swedish driving test
- 2013
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Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 19, s. 22-30
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to examine the consistency of examiner assessments of test-takers' performance on the Swedish driving test. The study included 535 tests and was designed so that the ordinary examiner and a supervising examiner assessed the same test-taker. The assessment was done on a two-grade rating scale (pass/fail). Since the result can be affected by factors associated with the test-taker and the two examiners, questionnaires were developed and these were filled in by the test-takers and the examiners. Information about the administration of the test was collected via a specially designed form filled in by the supervising examiner. Using this form, the ordinary examiners' performance was rated on a number of aspects. The result from the study indicated that the agreement between the assessments was very good. For 93% of the tests the two examiners chose the same mark on the two-grade scale. In the cases where ratings differed, the analysis indicated only a few systematic differences among variables designed to provide possible explanations for differences in opinion. However, none of these was problematic with respect to consistency of assessment. Results indicated that most tests were carried out in a satisfactory manner.
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| 18. |
- Andersson, Jan, 1965-, et al.
(författare)
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The complexity of changes in modal choice : A quasi-experimental study
- 2023
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Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 96:July, s. 36-47
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Tidskriftsartikel (refereegranskat)abstract
- Background: Changes in modal choice is argued to be one way to reduce the emission of greenhouse gases. Increasing modal choices in favour of more environmentally friendly travel modes requires a better understanding of how these choices are actually made. The first aim of this study is therefore to examine how modal choice is related to subjective experiences as perceived accessibility, perceived satisfaction , habit, both before , after an intervention promoting public transport. The second aim is to examine how modal choice is affected by the intervention. Finally, the third aim is to examine how subjective experiences as perceived accessibility, perceived satisfaction, and habit are affected by the intervention.Method: The design used is a before-and after-study with free public travel passes as the intervention (30-or 14-days free travel pass). Altogether, 52 travelers - distributed on two intervention groups and one control group - participated in the study. The 30-days free travel pass group constitutes 18 participants, the 14-days free travel pass group constitutes 19 participants while the control group constitutes 15 participants. During the before -period the participants were asked to register their modal choice using a digitalized application downloaded on their smart phones (the TravelVu app), to complete a short app-based questionnaire, and a web-based questionnaire. During the after-period, they were once again asked to register their modal choice and to complete a web-based questionnaire. All data collected were analyzed by variance or correlation analyses using the change between before-and after period as the dependent variable.Conclusion: The intervention did not affect the modal choice or the subjective experiences. Over time, the participants did however increase their use of public transport and their cognitive evaluation of their everyday travel overall, while they decreased their use of car and became less reflective and less interested in trying out new alternative travel modes. These changes might be attributed to their participation in the present study.
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| 19. |
- Aramrattana, Maytheewat, et al.
(författare)
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A simulation framework for cooperative intelligent transport systems testing and evaluation
- 2017
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Ingår i: Transportation Research Part F. - Kidlington : Pergamon Press. - 1369-8478 .- 1873-5517.
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Tidskriftsartikel (refereegranskat)abstract
- Connected and automated driving in the context of cooperative intelligent transport systems (C-ITS) is an emerging area in transport systems research. Interaction and cooperation between actors in transport systems are now enabled by the connectivity by means of vehicle-to-vehicle and vehicle-to-infrastructure (V2X) communication. To ensure the goals of C-ITS, which are safer and more efficient transport systems, testing and evaluation are required before deployment of C-ITS applications. Therefore, this paper presents a simulation framework—consisting of driving-, traffic-, and network-simulators—for testing and evaluation of C-ITS applications. Examples of cooperative adaptive cruise control (CACC) applications are presented, and are used as test cases for the simulation framework as well as to elaborate on potential use cases of it. Challenges from combining the simulators into one framework, and limitations are reported and discussed. Finally, the paper concludes with future development directions, and applications of the simulation framework in testing and evaluation of C-ITS. © 2017 Elsevier Ltd. All rights reserved.
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| 20. |
- Aramrattana, Maytheewat, et al.
(författare)
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Testing cooperative intelligent transport systems in distributed simulators
- 2019
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Ingår i: Transportation Research Part F. - : Elsevier Ltd. - 1369-8478 .- 1873-5517. ; 65, s. 206-216
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Tidskriftsartikel (refereegranskat)abstract
- Simulation is often used as a technique to test and evaluate systems, as it provides a cost-efficient and safe alternative for testing and evaluation. A combination of simulators can be used to create high-fidelity and realistic test scenarios, especially when the systems-under-test are complex. An example of such complex systems is Cooperative Intelligent Transport Systems (C-ITS), which include many actors that are connected to each other via wireless communication in order to interact and cooperate. The majority of the actors in the systems are vehicles equipped with wireless communication modules, which can range from fully autonomous vehicles to manually driven vehicles. In order to test and evaluate C-ITS, this paper presents a distributed simulation framework that consists of (a) a moving base driving simulator; (b) a real-time vehicle simulator; and (c) network and traffic simulators. We present our approach for connecting and co-simulating the simulators. We report on limitation and performance that this simulation framework can achieve. Lastly, we discuss potential benefits and feasibility of using the simulation framework for testing of C-ITS.
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| 21. |
- Bagdadi, Omar
(författare)
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Assessing safety critical braking events in naturalistic driving studies
- 2012
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Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 16, s. 117-126
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Tidskriftsartikel (refereegranskat)abstract
- Naturalistic driving studies permit the study of driving behaviour during every day driving. Such studies have a long duration and rare events such as near-crashes and even crashes do occur during the period of the study. This fact gives an opportunity to study events that are otherwise difficult to find. However, the vast amount of data recorded within these naturalistic driving studies demands a huge amount of manual work to identify hazardous situations. This paper concerns the development and validation of a new method, based on critical jerk, to identify safety critical braking events during car driving. The method was compared with one of today's most used method, which is based on the longitudinal acceleration measure. Both methods were applied on near-crash data from the 100-car naturalistic driving study previously carried out by the Virginia Tech Transportation Institute (VTTI). The data included 637 near-crashes. The results from the analyses showed that the critical jerk method performed approximately 1.6 times higher overall success rate than the method based on the longitudinal acceleration measure. In addition, a positive correlation was found between driver's safety critical braking event and crash involvement. The conclusion is that the critical jerk method is capable of detecting safety critical braking events and may also be used for assessing high risk drivers.
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| 22. |
- Bakhtiary, Mohammadreza, et al.
(författare)
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A tree-based extended model to predict intention to speed for taxi drivers
- 2024
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Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 103, s. 190-200
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Tidskriftsartikel (refereegranskat)abstract
- The need to predict and understand drivers’ intention to violate emphasizes the importance of developing a model based on the motives behind the action. This study aims to develop a model to predict a taxi driver’s intention to speed in an urban area using variables including psychological factors, demographic information, and exposure. Aggregate (factor-based) and disaggregate (item-based) models of input variables will also be compared. In this study, the self-reported data on Tehran taxi drivers was collected in the form of a scenario-based questionnaire which is inspired by the Theory of Planned Behaviour (TPB). The intention to commit violations was predicted and modelled using stepwise regression and decision tree regression models. The results, based on the stepwise regression model showed a higher value of fitting score for an item-based linear model (R2 = 0.695), but the final model using the tree-based regression presented a better fit for the factored model (R2 = 0.746) considering the cross-validated model with the lowest deviation criteria (RMSD = 0.26). Furthermore, in this model attitude made the greatest contribution to the prediction of intention. The results obtained from the two different modelling approaches showed that exposure and age did not have much effect on the models. A main advantage of the current study is that the variables were compared and refined in two stages of exploratory factor analysis and stepwise regression before being entered into the tree regression model. In addition, the results of the factor-based model were compared with the item-based model.
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| 23. |
- Bazilinskyy, Pavlo, et al.
(författare)
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Take-over requests in highly automated driving : A crowdsourcing survey on auditory, vibrotactile, and visual displays
- 2018
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Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 56, s. 82-98
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Tidskriftsartikel (refereegranskat)abstract
- An important research question in the domain of highly automated driving is how to aid drivers in transitions between manual and automated control. Until highly automated cars are available, knowledge on this topic has to be obtained via simulators and self-report questionnaires. Using crowdsourcing, we surveyed 1692 people on auditory, visual, and vibrotactile take-over requests (TORs) in highly automated driving. The survey presented recordings of auditory messages and illustrations of visual and vibrational messages in traffic scenarios of various urgency levels. Multimodal TORs were the most preferred option in high-urgency scenarios. Auditory TORs were the most preferred option in low-urgency scenarios and as a confirmation message that the system is ready to switch from manual to automated mode. For low-urgency scenarios, visual-only TORs were more preferred than vibration-only TORs. Beeps with shorter interpulse intervals were perceived as more urgent, with Stevens’ power law yielding an accurate fit to the data. Spoken messages were more accepted than abstract sounds, and the female voice was more preferred than the male voice. Preferences and perceived urgency ratings were similar in middle- and high-income countries. In summary, this international survey showed that people's preferences for TOR types in highly automated driving depend on the urgency of the situation.
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| 24. |
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| 25. |
- Bianchi Piccinini, Giulio, 1982, et al.
(författare)
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Influence of oncoming traffic on drivers’ overtaking of cyclists
- 2018
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Ingår i: Transportation Research Part F: Traffic Psychology and Behaviour. - : Elsevier BV. - 1369-8478. ; 59:Part A, s. 378-388
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Tidskriftsartikel (refereegranskat)abstract
- Active transportation - such as cycling - can provide health benefits to the population. However, cycling safety remains a major threat to favour the use of bicycles and, for this reason, more efforts are needed to reduce the number of crashes involving cyclists. One crash scenario which deserves special attention is driver’s overtaking of cyclists since it has an increased likelihood to lead to severe injuries. During the overtaking manoeuvre, the monitoring of subjective risk can influence the decision-making process and lead to different outcomes. In this context, the present driving simulator study aims to investigate how the time to collision between oncoming traffic and subject vehicle affected the overtaking strategy, and the minimum safety margins towards the overtaken cyclist. The results show that a decrease in time to collision against the oncoming vehicle significantly affects the drivers’ overtaking strategy (accelerative vs. flying), inducing more drivers to choose an accelerative overtaking manoeuvre. The decrease in time to collision also produces a decrease in minimum safety margins to the cyclists for drivers who opt for a flying overtaking strategy. Finally, the current research shows that the minimum lateral safety margins were smaller and the mean speed higher in flying manoeuvres compared to accelerative manoeuvres. Overall, the combination of lower safety margins and higher mean speeds in flying overtaking manoeuvres seems to pose a risk for cyclists’ safety. The findings of the study provide some implications for the design of automated driving.
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