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1.	Radun, Igor, et al. (författare) Company employees as experimental participants in traffic safety research : Prevalence and implications 2019 Ingår i: Transportation Research Part F. - Stockholm : Elsevier BV. - 1369-8478 .- 1873-5517. ; 60, s. 81-92 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.
2.	Falkmer, Torbjörn, et al. (författare) Fixation patterns of learner drivers with and without cerebral palsy (CP) when driving in real traffic environments 2001 Ingår i: Transportation Research Part F. - 1369-8478 .- 1873-5517. ; 4:3, s. 171-185 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.
3.	Hakamies-Blomqvist, L., et al. (författare) Driver ageing does not cause higher accident rates per km 2002 Ingår i: Transportation Research Part F. - 1369-8478 .- 1873-5517. ; 5:4, s. 271-274 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.
4.	Hatakka, Mika, et al. (författare) From control of the vehicle to personal self-control, broadening the perspectives to driver education 2002 Ingår i: Transportation Research Part F. - 1369-8478 .- 1873-5517. ; 5:3, s. 201-215 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.
5.	Lundberg, C., et al. (författare) Driving tests with older patients : Effect of unfamiliar versus familiar vehicle 2003 Ingår i: Transportation Research Part F. - 1369-8478 .- 1873-5517. ; 6:3, s. 163-173 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.
6.	Rimmo, P.-A., et al. (författare) Older drivers' aberrant driving behaviour, impaired activity, and health as reasons for self-imposed driving limitations 2002 Ingår i: Transportation Research Part F. - 1369-8478 .- 1873-5517. ; 5:1, s. 345-360 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.
7.	Vogel, Katja (författare) What characterizes a free vehicle in an urban area? 2002 Ingår i: Transportation Research Part F. - 1369-8478 .- 1873-5517. ; 5:1, s. 313-327 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
8.	Abenoza, Roberto, et al. (författare) Determinants of traveler satisfaction : Evidence for non-linear and asymmetric effects 2019 Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 66, s. 339-356 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.
9.	af Wåhlberg, Anders, 1965- (författare) Changes in Driver Celeration Behavior over Time : do Drivers Learn from Collisions? 2012 Ingår i: Transportation Research Part F. - : Elsevier BV. - 1369-8478 .- 1873-5517. ; 15:5, s. 471-479 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.
10.	af Wåhlberg, Anders, 1965- (författare) Re-education of young driving offenders : Effects on recorded offences and self-reported collisions 2011 Ingår i: Transportation Research Part F. - : Elsevier BV. - 1369-8478 .- 1873-5517. ; 14:4, s. 291-299 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.
11.	af Wåhlberg, Anders, 1965-, et al. (författare) The effect of social desirability on self reported and recorded road traffic accidents 2010 Ingår i: Transportation Research Part F. - : Elsevier BV. - 1369-8478 .- 1873-5517. ; 13:2, s. 106-114 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.
12.	Ahlström, Christer, et al. (författare) Bicyclists’ visual strategies when conducting self-paced vs. system-paced smartphone tasks in traffic 2015 Ingår i: Transportation Research Part F. - : Elsevier BV. - 1369-8478 .- 1873-5517. ; 41, s. 204-216 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.
13.	Alger, Susanne, 1967-, et al. (författare) Agreement of driving examiners' assessments : evaluating the reliability of the Swedish driving test 2013 Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 19, s. 22-30 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.
14.	Andersson, Jan, 1965-, et al. (författare) The complexity of changes in modal choice : A quasi-experimental study 2023 Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 96:July, s. 36-47 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.
15.	Aramrattana, Maytheewat, et al. (författare) A simulation framework for cooperative intelligent transport systems testing and evaluation 2017 Ingår i: Transportation Research Part F. - Kidlington : Pergamon Press. - 1369-8478 .- 1873-5517. 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.
16.	Aramrattana, Maytheewat, et al. (författare) Testing cooperative intelligent transport systems in distributed simulators 2019 Ingår i: Transportation Research Part F. - : Elsevier Ltd. - 1369-8478 .- 1873-5517. ; 65, s. 206-216 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.
17.	Bagdadi, Omar (författare) Assessing safety critical braking events in naturalistic driving studies 2012 Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 16, s. 117-126 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.
18.	Bakhtiary, Mohammadreza, et al. (författare) A tree-based extended model to predict intention to speed for taxi drivers 2024 Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 103, s. 190-200 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.
19.	Bazilinskyy, Pavlo, et al. (författare) Take-over requests in highly automated driving : A crowdsourcing survey on auditory, vibrotactile, and visual displays 2018 Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 56, s. 82-98 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.
20.	Björklund, Gunilla, 1973-, et al. (författare) Driver behaviour in intersections : Formal and informal traffic rules 2005 Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 8:3, s. 239-253 Tidskriftsartikel (refereegranskat)abstract Drivers' behaviour in intersections is not only influenced by the rules of priority in the intersection but also by the design of the intersection as well as the behaviour of other road users. If behaviours that supplement or contradict formal traffic rules become common in a particular traffic intersection, it is an indication that an informal traffic rule has been used. In the present study a sample of 1276 Swedish drivers (aged 18-74 years) responded to questions about how often they would yield to another driver in 10 hypothetical crossing situations. In all crossing situations the respondents were told that there was no major road, implying that they should always yield the right of way to traffic coming from the right (the right-hand ride). The results showed that drivers' reported behaviour varied over different intersections. As expected, the formal rule of priority (i.e., the direction from which the other driver was coming) was an important determinant for drivers' yielding behaviour. However, cues for informal rules such as the other driver's behaviour and road breadth were also of importance. Different groups of drivers could be identified according to their strategies of yielding behaviour. One group of drivers reported that they rarely yielded, whereas another group reported that they always did so. A third group complied with the right-hand rule most of the time, whereas the behaviour of a fourth group varied over intersections. The implications of the results and the appropriateness of the right-hand rule are discussed.
21.	Blissing, Björn, 1978-, et al. (författare) Driver behavior in mixed and virtual reality : A comparative study 2019 Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 61, s. 229-237 Tidskriftsartikel (refereegranskat)abstract This paper presents a comparative study of driving behavior when using different virtual reality modes. Test subjects were exposed to mixed, virtual, and real reality using a head mounted display capable of video see-through, while performing a simple driving task. The driving behavior was quantified in steering and acceleration/deceleration activities, divided into local and global components. There was a distinct effect of wearing a head mounted display, which affected all measured variables. Results show that average speed was the most significant difference between mixed and virtual reality, while the steering behavior was consistent between modes. All subjects but one were able to successfully complete the driving task, suggesting that virtual driving could be a potential complement to driving simulators.
22.	Booth, Leon, et al. (författare) Experiences of older adults interacting with a shared autonomous vehicle and recommendations for future implementation 2022 Ingår i: Transportation Research Part F. - : ELSEVIER SCI LTD. - 1369-8478 .- 1873-5517. ; 90, s. 100-108 Tidskriftsartikel (refereegranskat)abstract Introduction: A recognised potential benefit of autonomous vehicles is increased mobility for older adults. However, this group is more apprehensive about adoption, which may hinder uptake. Shared autonomous vehicles (SAVs) represent a use case that may be especially relevant for older people due to emerging applications in retirement villages and similar precincts. However, little research has examined the SAV-related concerns of older adults and strategies to address them. This study used an exploratory approach involving SAV exposure to identify strategies that may increase older people's receptiveness to SAVs. Method: Older adults living in retirement villages (n = 63) were interviewed while interacting with an SAV to examine their needs, expectations, and concerns regarding SAVs. The interview data were coded and thematically analysed. Results: Participants recommended the following approaches to ensuring SAVs are useful and acceptable to older adults: providing physical accessibility for those with mobility impairments, comfortable and practical internal layouts, and operating SAVs on convenient routes at useful speeds. Strategies such as exposing older adults to SAVs in operation to encourage uptake and initially ensuring a human assistant is present were suggested methods of increasing receptivity. Discussion: The findings suggest older passengers are likely to share many of the same reactions to SAVs as the broader population, but with a stronger focus on issues relating to accessibility and the physical layout of the vehicles. The solutions to these issues suggested by the study participants may be useful for those designing SAVs for use in older people's settings and beyond.
23.	Broström, Robert, et al. (författare) Individual glance strategies and their effect on the NHTSA visual manual distraction test 2016 Ingår i: Transportation Research Part F. - : Elsevier BV. - 1369-8478 .- 1873-5517. ; 36, s. 83-91 Tidskriftsartikel (refereegranskat)abstract The purpose of this paper was to investigate how individual differences in glance strategy could impact the glance performance test defined in the NHTSA visual manual distraction guidelines. Better understanding of the test procedure could help development of new technology for safe driving. A custom in-vehicle information system was developed and assessed in a driving simulator by eighteen participants. The interfaces were designed according to recommendations in the NHTSA guidelines and contained manual radio-tuning tasks, sound settings tasks and six letter spelling tasks. Two of the six tested interfaces fully complied with the test. In addition, clear individual differences in glance strategy were found among the participants. Four individual glance strategies were identified. Two of these, long glancers and frequent glancers, highly affected the outcome of the compliance test. Participants belonging to the long glancers and the frequent glancers categories were identified as statistical outliers in many test cases. For example, if the individual values of these participants were replaced with sample mean, the number of complying interfaces would increase to five out of six, which is more in line with expectations for these interfaces. The results of this study show that individual variations in glance strategy exist. Also, these individual variations seem to have a non- negligible influence on the result when performance-testing of in-vehicle interfaces is done according to the NTHSA guidelines.
24.	Cacciabue, Pietro Carlo, et al. (författare) Unified Driver Model simulation and its application to the automotive, rail and maritime domains 2013 Ingår i: Transportation Research Part F. - : Elsevier BV. - 1369-8478 .- 1873-5517. ; 21, s. 315-327 Tidskriftsartikel (refereegranskat)abstract This paper describes the implementation of a model of a driver into a computerised numerical simulation. The model is developed to capture the essential characteristics and common aspects of cognition and behaviour of a human being in control of a “vehicle” in different surface transport systems, namely trains, cars and ships. The main functions of the simulation are discussed as well as the experiments carried out in different types of driving simulators to support the estimation of the parameters utilised in the numerical simulation. The validation processes carried out in the rail and maritime domains are also discussed together with a critical review of capacities and limitations of the proposed approach.
25.	Coogan, Matthew A, et al. (författare) Examining behavioral and attitudinal differences among groups in their traffic safety culture 2014 Ingår i: Transportation Research Part F. - : Elsevier BV. - 1369-8478 .- 1873-5517. ; 26:PB, s. 303-316 Tidskriftsartikel (refereegranskat)abstract The paper explores the concept that, for a given population, there is not a single "traffic safety culture," but rather a set of alternative cultures in which the individual driver might belong. There are several different cultures of dangerous driving behavior and each might need a separate strategy for intervention or amelioration.First, the paper summarizes the over-arching theory explored in the research, which applies Multi-group Structural Equation Modeling (MSEM) in a modification of the Theory of Planned Behavior (TPB) in the explanation of Risky Driving Behavior, based on ten observed explanatory factors.Second, we apply Latent Class Cluster (LCC) segmentation to the full sample, revealing four segments: one cluster reflecting a "Low Risk Driving Safety Group" and three clusters describing three different groups of problematic drivers. We first apply MSEM to two groups; the "Low Risk Driving Safety Group," and the "High Risk Driving Safety Group," defined as the members of the three problematic clusters together, revealing how a "Low Risk" culture differs from the "High Risk" culture, with the relative importance of the TPB explanatory factors varying sharply between the two groups.Finally, the three problematic clusters are profiled for demographics and their mean scores for the ten observed explanatory factors. Each of the clusters is reviewed in terms of responses to selected survey questions.Three separate and distinct dangerous traffic safety cultures emerge: first, a culture of risky driving dominated by excitement seeking and optimism bias; a second dominated by denial of societal values; and a third characterized by its propensity to find rational justifications for its speeding behavior.The paper applies two research methods together: LCC segmentation divides our sample into meaningful subgroups, while MSEM reveals both within-group analysis of variance and between-group differences in safety attitudes and outcomes. The paper concludes that the combination of the segmentation powers of the LCC and the analysis powers of the MSEM provides the analyst with an improved understanding of the attitudes and behaviors of the separate groups, all tied back to the over-arching theory underlying the research.
26.	Eriksson, Louise, et al. (författare) Expected car use reduction in response to structural travel demand management measures 2010 Ingår i: Transportation Research Part F. - : Elsevier Ltd. - 1369-8478 .- 1873-5517. ; 13, s. 329-342 Tidskriftsartikel (refereegranskat)abstract Selecting the appropriate travel demand management (TDM) measures aiming to reduce the environmental problems associated with private transportation demands a thorough understanding of the behavioral consequences of different measures. In this scenario based study, the expected car use reduction in response to one push measure (i.e. raised tax on fossil fuel), one pull measure (i.e. improved public transport), and a combination of the two measures were analyzed. The aim was to compare the expected car use reduction in response to the different TDM measures, the car use reduction strategies used to achieve this reduction, and factors important for the expected car use reduction (i.e. background factors, internal motivational factors (general intention and personal norm), and perceived personal impact of the measure). In a two step between-subject design, a sample of car users first answered a pre-questionnaire and subsequently three groups of car users (N = 274) each evaluated one of the TDM measures. Results demonstrated that the combined measure led to larger expected car use reduction compared to the measures evaluated individually and the reduction was mainly expected to be made by means of trip chaining and changing travel mode. Moreover, internal motivational factors, such as personal norm or general intention, and the perceived impact of the measure, were found to be important for the expected car use reduction in response to the TDM measures.
27.	Eriksson, Louise, 1973-, et al. (författare) Interrupting habitual car use : The importance of car habit strength and moral motivation for personal car use reduction 2008 Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 11:1, s. 10-23 Tidskriftsartikel (refereegranskat)abstract In this study, habitual car use was interrupted by means of an intervention attempting to induce a deliberate consideration to reduce personal car use and forming implementation intentions for the planned changes in travel behavior. The importance of car habit strength and of moral motivation for reducing car use was analyzed. The study was conducted as a field experiment where 71 car users were recruited to either an experimental group or a control group. All participants reported car habit strength and moral motivation to reduce car use (i.e. personal norm) by means of a questionnaire, and recorded car use by means of weekly car diaries pre- and post-intervention. Results demonstrate that the intervention did make the choice of travel mode more deliberate since the association between car use and car habit strength were weakened while the relation between car use and personal norm were strengthened after compared to before the intervention. Moreover, as a result of the intervention car users with a strong car habit and a strong personal norm were found to be more likely to reduce car use as compared to those with a weak car habit and a weak personal norm. Hence, a reduction in car use may be facilitated by interrupting habitual car use, specifically if the car user has a strong car habit and a strong moral motivation to reduce personal car use.
28.	Eriksson, Lars, et al. (författare) Performance and presence with head-movement produced motion parallax in simulated driving 2015 Ingår i: Transportation Research Part F. - : Elsevier BV. - 1369-8478 .- 1873-5517. ; 34, s. 54-64 Tidskriftsartikel (refereegranskat)abstract Driving simulator studies can reveal relevant and valid aspects of driving behavior, but underestimation of distance and speed can negatively affect the driver's performance, such as in performance of overtaking. One possible explanation for the underestimation of distance and speed is that two-dimensional projection of the visual scene disrupts the monocular-based illusory depth because of conflicting binocular and monocular information of depth. A possible solution might involve the strengthening of the monocular information so that the binocular information becomes less potent.In the present study, we used an advanced high-fidelity driving simulator to investigate whether adding the visual depth information of motion parallax from head movement affects sense of presence, judgment of distance and speed, and performance measures coupled with overtaking. The simulations included two types of driving scenario in which one was urban and the other was rural. The main results show no effect of this head-movement produced motion parallax on sense of presence, head movement, time to collision, distance judgment, or speed judgment.However, the results show an effect on lateral positioning. When initiating the overtaking maneuver there is a lateral positioning farther away from the road center as effect of the motion parallax in both types of scenario, which can be interpreted as indicating use of naturally occurring information that change behavior at overtaking. Nevertheless, only showing tendencies of effects, absent is any clear additional impact of this motion parallax in the simulated driving.
29.	Eriksson, Lars, 1967-, et al. (författare) Stated reasons for reducing work-commute by car 2008 Ingår i: Transportation Research Part F. - : Elsevier BV. - 1369-8478 .- 1873-5517. ; , s. 427-433 Tidskriftsartikel (refereegranskat)
30.	Esmaeilikia, Mahsa, et al. (författare) Bicycle helmets and risky behaviour : A systematic review 2019 Ingår i: Transportation Research Part F. - : Elsevier BV. - 1369-8478 .- 1873-5517. ; 60, s. 299-310 Forskningsöversikt (refereegranskat)abstract A long-standing argument against bicycle helmet use is the risk compensation hypothesis, i.e., increased feelings of safety caused by wearing a helmet results in cyclists exhibiting more risky behaviour. However, past studies have found helmet wearing is not associated with risky behaviour, e.g., committing a traffic violation was positively associated with a lower frequency of helmet use. There is a lack of consensus in the research literature regarding bicycle helmet use and the risk compensation hypothesis, although this gap in knowledge was identified in the early 2000s. This is the first study to carry out a systematic review of the literature to assess whether helmet wearing is associated with risky behaviour. Two study authors systematically searched the peer-reviewed literature using five research databases (EMBASE, MEDLINE, COMPENDEX, SCOPUS, and WEB OF SCIENCE) and identified 141 unique articles and four articles from other sources. Twenty-three articles met inclusion criteria and their findings were summarised. Eighteen studies found no supportive evidence helmet use was positively associated with risky behaviour, while three studies provided mixed findings, i.e., results for and against the hypothesis. For many of these studies, bicycle helmet wearing was associated with safer cycling behaviour. Only two studies conducted from the same research lab provided evidence to support the risk compensation hypothesis. In sum, this systematic review found little to no support for the hypothesis bicycle helmet use is associated with engaging in risky behaviour.
31.	Ettema, Dick, et al. (författare) Satisfaction with travel and subjective well-being (SWB) : Development and tests of a measurement tool 2011 Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 14:3, s. 167-175 Tidskriftsartikel (refereegranskat)
32.	Falk, Birgitta, et al. (författare) Promoting traffic safety among young male drivers by means of elaboration-based interventions 2009 Ingår i: Transportation Research Part F. - : Elsevier BV. - 1369-8478 .- 1873-5517. ; 12:1, s. 1-11 Tidskriftsartikel (refereegranskat)abstract Previous research in social psychology has brought about significant changes in attitudes and behaviour by merely asking respondents to imagine, or reflect, on a phenomenon and arrive at their own conclusions. To test the potential of such interventions in the traffic safety area, an experiment comprising 353 young men 18–23 years old with a driver’s licence was conducted. Two experimental groups were induced to imagine a severe accident scenario and to visualize their feelings and the consequences on their future lives. A control group was interviewed about neutral issues. Attitudes towards risk-taking were measured post-intervention and at follow-up. The experimental groups showed more “ideal” attitudes than the control group post-intervention. At follow-up the attitudes of the experimental group remained unchanged, whereas the control group had changed towards more “ideal” attitudes. Self-reported risk-taking behaviour was measured pre-intervention and at follow-up. At follow-up all groups reported significantly less risk-taking behaviour than at pre-intervention. It is suggested that answering the questionnaires increased mental elaboration concerning risky driving, and it is concluded that interventions that unobtrusively make drivers reflect on their driving should be explored further as a means to promote traffic safety.
33.	Falkmer, Torbjörn, et al. (författare) Driver education for persons with cerebral palsy : a retrospective study of educational problems. 2000 Ingår i: Transportation Research Part F. - 1369-8478 .- 1873-5517. ; 3:1, s. 15-27 Tidskriftsartikel (refereegranskat)
34.	Falkmer, Torbjörn, et al. (författare) Fixation patterns of learner drivers with and without cerebral palsy (CP) when driving in real traffic environments 2001 Ingår i: Transportation Research Part F. - 1369-8478 .- 1873-5517. ; 4:3, s. 171-185 Tidskriftsartikel (populärvet., debatt m.m.)
35.	Farah, Haneen, et al. (författare) Passing behavior on two-lane highways 2010 Ingår i: Transportation Research Part F. - : Elsevier BV. - 1369-8478 .- 1873-5517. ; 13:6, s. 355-364 Tidskriftsartikel (refereegranskat)abstract Two-lane highways make up a substantial proportion of the road network in most of the world. Passing is among the most significant driving behaviors on two-lane highways. It substantially impacts the highway performance. Despite the importance of the problem, few studies attempted to model passing behavior. In this research, a model that attempts to capture both drivers' desire to pass and their gap acceptance decisions to complete a desired passing maneuver is developed and estimated using data on passing maneuvers collected with a driving simulator. Sixteen different scenarios were used in the experiment in order to capture the impact of factors related to the various vehicles involved, the road geometry and the driver characteristics in the model. A passing behavior model is developed that includes choices in two levels: the desire to pass and the decision whether or not to accept an available passing gap. The probability to complete a passing maneuver is modeled as the product of the probabilities of a positive decision on both these choices. The estimation results show that modeling the drivers' desire to pass the vehicle in front has a statistically significant contribution in explaining their passing behavior. The two sub-models incorporate variables that capture the impact of the attributes of the specific passing gap that the driver evaluates and the relevant vehicles, the geometric characteristics of the road section and the driver characteristics and account for unobserved heterogeneity in the driver population.
36.	Friman, Margareta (författare) Affective dimensions of the waiting experience 2010 Ingår i: Transportation Research Part F. - 1369-8478 .- 1873-5517. ; 13:3, s. 197-205 Tidskriftsartikel (refereegranskat)
37.	Friman, Margareta, 1970-, et al. (författare) Are we leaving some people behind? Travel autonomy, perceived accessibility, and well-being among people experiencing mental and physical difficulties 2023 Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 98, s. 243-253 Tidskriftsartikel (refereegranskat)abstract This study focuses on the association between cognitive, medical, and physical difficulties; mental illness; travel autonomy; and perceptions of the possibilities of participating in desired daily activities; further, we examine their association with happiness and life satisfaction. We present and empirically test an integrated framework with travel autonomy, defined as the prerequisites, freedom, and possibility to travel the way one wants, at its core. We use web survey data (n = 1041) collected in Sweden in 2021. Using partial least squares structural equations, we find a valid and reliable model with travel autonomy as a distinct and reliable latent construct. Furthermore, travel autonomy yields significant paths to perceived accessibility, happiness, and life satisfaction, highlighting the importance of capabilities, independent travel, freedom, and possibilities in the overall construct of travel autonomy. Finally, mental illness plays an important role in how people rate their travel autonomy.
38.	Friman, Margareta, 1970-, et al. (författare) Travel and residual emotional well-being 2017 Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 49, s. 159-176 Tidskriftsartikel (refereegranskat)abstract This study addresses the question of how work commutes change positive versus negative and active versus passive mood experienced after the commutes. Analyses are presented for 230 time-sampled morning commutes to work, made by 146 randomly sampled people in three different Swedish cities, asking them to use smartphones to report mood before, directly after, and later in the work place after the commute. The results show that selfreported positive emotional responses evoked by critical incidents are related to mood changes directly after the commute but not later in the day. It is also shown that satisfaction with the commute, measured retrospectively, is related to travel mode, travel time, as well as both positive and negative emotional responses to critical incidents.
39.	Grane, Camilla, et al. (författare) Driving performance during visual and haptic menu selection with in-vehicle rotary device 2013 Ingår i: Transportation Research Part F. - : Elsevier BV. - 1369-8478 .- 1873-5517. ; 18, s. 123-135 Tidskriftsartikel (refereegranskat)abstract An in-vehicle haptic rotary device developed to interact with secondary tasks can provide haptic support to a visual interface and reduce the need to look away from the road. However, added haptic information intended to support interaction may distract the driver by adding cognitive load. This study examines how visual and haptic interfaces affect driver performance and if visual–haptic information could reduce effects of driver distraction. Four menu selection interfaces were compared: visual-only, visual–haptic with partly haptic support, visual–haptic with full haptic support, and haptic-only. The Lane Change Test was used with four measures. Interaction with the interfaces while driving caused increased driving deviation and delayed lane change initiation. The visual-only and the visual–haptic interface with partly haptic support caused erroneous crossed lanes. The haptic-only interface caused missed road signs. Full haptic support had the least negative effect on driver performance. In conclusion, haptic support could reduce effects of visual load without adding effects of cognitive load.
40.	Gössling, Stefan (författare) Advancing a Clinical Transport Psychology 2013 Ingår i: Transportation Research. Part F: Traffic Psychology and Behaviour. - : Elsevier BV. - 1369-8478 .- 1873-5517. ; 19, s. 11-21 Tidskriftsartikel (refereegranskat)
41.	Haustein, Sonja, et al. (författare) Risky and anxious-aggressive drivers : A key barrier to traffic safety legislation in Germany 2022 Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 89, s. 84-96 Tidskriftsartikel (refereegranskat)abstract Traffic safety is high on the agenda of European governments. Yet, countries including Germany maintain policies that are commonly identified as increasing traffic risks, such as speed limits set too high or trends of greater car motorization and mass. To better understand some of the interrelationships of driver characteristics and car segments, this paper identifies different groups of drivers, based on a representative sample of German automobilists (n = 1211). Psychological instruments used to identify driver segments include the Driver Behavior Questionnaire (DBQ), the Multidimensional Driving Style Inventory (MDSI), and the HEXACO Personality Inventory. Based on k-means clustering, we identified four distinct groups: Risky drivers, Showy anxious aggressive drivers, Anxious drivers and Calm drivers. Questions focused on sociodemographics, political orientation, and traffic laws are used to describe these psychographic segments. Findings suggest that Risky and Showy anxious-aggressive drivers represent a greater threat to traffic safety than other driver segments for different reasons: they drive more powerful and larger cars, deliberately violate traffic laws - creating unsafe traffic conditions for others -, and oppose legislation making traffic safer, while also voting for parties holding on to the status quo. As their political choices appear dominated by automobile interests, there are widespread implications for society.
42.	Kharrazi, Sogol, 1980-, et al. (författare) Assessing dynamics of heavy vehicles in a driving simulator 2019 Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 65, s. 306-315 Tidskriftsartikel (refereegranskat)abstract This article investigates the potential of a motion based driving simulator in assessing and comparing dynamic performance of different heavy vehicles. A driving simulator study with 55 professional truck drivers is performed and the achieved results show a strong correlation between the objective and subjective measures of the different vehicles performance. The motion based driving simulator is used to compare the performance and controllability of high capacity transport vehicles with conventional heavy vehicles.
43.	Kircher, Katja, 1973-, et al. (författare) A comparison of glance coding approaches for driver attention assessment 2024 Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 100, s. 243-253 Tidskriftsartikel (refereegranskat)abstract Eye tracking is a common tool to assess drivers’ attentional state, either in real-time with the goal to prevent incidents, or offline, to understand underlying processes. While seemingly objective, eye tracking data can be coded and interpreted in different ways, which can have substantial effects on the results. The objective of this paper is to highlight and discuss the possibilities and limitations of three different approaches to code glance data: the direction-based encoding, the target-based approach, and the purpose-based approach. The direction-based coding scheme describes glances relative to the direction of travel. The target-based approach classifies the glance targets into different categories. The purpose-based approach needs additional layers of information to deduce the reason for the glance. This information encompasses road layout, traffic rules, and the presence and relevance of other traffic.Data from a field study with 23 participants driving an instrumented vehicle on an urban route was used to illustrate differences between the three methods. The results showed that the coding approach clearly affected the interpretation of the measured glance data. A purely target-based approach is limited by its inability to account for spare visual capacity and that also the absence of a target constitutes valuable information, and a purely direction-based approach does not account for the need to scan areas located off forward. The purpose-based approach requires contextual information that can be cumbersome to integrate. Regardless of the approach used, additional layers of contextual information increase understanding and interpretability, potentially at the cost of increased complexity. The three approaches are suitable for different contexts and their feasibility also depends on the availability of additional data. A key message is that context awareness improves the accuracy of driver attention monitoring and inattention identification.
44.	Kircher, Katja, 1973-, et al. (författare) Attentional requirements on cyclists and drivers in urban intersections 2020 Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 68, s. 105-117 Tidskriftsartikel (refereegranskat)abstract Even though often travelling on the same roads, it has been shown that cyclists and car drivers interpret their environment differently, which can lead to misunderstandings and collisions. Based on the Minimum Required Attention (MiRA) theory and the Salience, Effort, Expectancy, Value (SEEV) model, it is investigated whether the attentional requirements put on drivers and cyclists are different in urban intersections, and how difficult it is to fulfil the requirements for the two road user groups. Additionally, glance data from 23 participants who both cycled and drove along an urban route are compared with respect to information sampling strategies and the fulfilment of attentional requirements depending on its type for three intersections. Generally, more attentional requirements existed for cyclists, and due to where they occur relative to the infrastructure, in combination with the physical aspects of cycling, they are less likely to be fulfilled. This was also corroborated by the empirical data, which showed that requirements clearly visible from the infrastructural design are fulfilled more often than those that are not. Overall, the theoretical evaluation of the infrastructure was confirmed by the empirical data, such that the proposed method can be used as a starting point for a theoretical, human centred evaluation of traffic infrastructure. (C) 2019 Elsevier Ltd. All rights reserved.
45.	Kircher, Katja, 1973-, et al. (författare) Bicyclists‘ speed adaptation strategies when conducting self-paced vs. system-paced smartphone tasks in traffic 2015 Ingår i: Transportation Research Part F. - : Elsevier BV. - 1369-8478 .- 1873-5517. ; 28, s. 55-64 Tidskriftsartikel (refereegranskat)abstract The increasing prevalence of mobile phone usage while cycling has raised concerns, even though the number of cyclists involved in accidents does not increase at a comparable rate. A reason for this may be how cyclists adapt travelling speed and task execution to the current traffic situation. The aim of this study is to investigate speed adaptation among cyclists when conducting self-paced (initiated by the cyclist) vs. system-paced (initiated by somebody else) smartphone tasks in real 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 clearly show that cyclists use conscious strategies to adapt their speed to accommodate the execution of secondary phone tasks. Regarding tactical behaviour, it was found that cyclists kept on cycling in 80% of the system-paced cases and in 70% of the self-paced cases. In the remaining cases, the cyclists chose to execute the phone task while standing still or when walking. Compared to the baseline (17.6 ± 3.5 km/h), the mean speed was slightly increased when the cyclists listened to music (18.2 ± 3.7 km/h) and clearly decreased when they interacted with the phone (13.0 ± 5.0 km/h). The speed reduction profile differed between self-paced and system-paced tasks with a preparatory speed reduction before task initiation for self-paced tasks. In conclusion, when the cyclists had the chance they either stopped or adapted their speed proactively to accommodate the execution of the phone task. For self-paced tasks, the speed reduction was finalised before task initialisation, and for system-paced tasks the speed adaptation occurred in reaction to the incoming task. It is recommended to investigate whether the observed compensatory behaviour is enough to offset the possible negative effects of smartphone use.
46.	Kircher, Katja, 1973-, et al. (författare) Continuous versus intermittent presentation of visual eco-driving advice 2014 Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 24, s. 27-38 Tidskriftsartikel (refereegranskat)abstract Automatic eco-driving advice has the potential to improve fuel economy and reduce emissions. However, providing eco-driving information to the driver will inevitably draw attention away from the driving task. The objective of this research is to investigate the effects of intermittent versus continuous visual eco-driving information on glance behaviour in an attempt to find the best approach to display eco-driving information from a traffic safety perspective.Twenty-eight truck drivers drove on a village road, a rural road and a motorway section in an advanced moving base truck simulator. A number of situations with relevance for eco-driving, such as traffic lights, crests, changes in posted speed limits, and a motorway entrance, were investigated. The level of difficulty of the traffic situations varied. Four conditions were tested: baseline without eco-driving information, intermittent feedback, continuous feedback and self-selected feedback (personalised settings selected by the driver).As expected, the drivers looked at the eco-driving system when it was active, and more so when the traffic situation was less demanding. Importantly, drivers waited longer with their first glance at the display when the traffic situation was more complex. In conclusion, intermittent information is recommended over continuous information as it leads to shorter dwell times, and as it is easier for the system designer to control when the periods of increased glance frequency occur, by presenting the information in strategically advantageous locations that are not demanding for the driver.
47.	Kircher, Katja, 1973-, et al. (författare) Cyclist efficiency and its dependence on infrastructure and usual speed 2018 Ingår i: Transportation Research Part F. - : Elsevier Ltd. - 1369-8478 .- 1873-5517. ; 54, s. 148-158 Tidskriftsartikel (refereegranskat)abstract Bicyclists are a heterogeneous group, with varying abilities, traffic education and experience. While efficiency was identified as an important factor on utility bicycle trips, it might be traded for experienced safety, for example by choosing different pathways in a given situation, or by relinquishing one's right of way. In a semi-controlled study with 41 participants, a grouping was made according to self-reported riding speed in relation to other cyclists. The participants cycled twice along a 3 km inner-city route, passing four intersections with different priority rules. The cyclists were free to choose how to negotiate the intersections. Speed and the traffic surroundings were recorded via gps and cameras on the bike of the participant and of a following experimenter. For each cyclist, the ‘base’ speed on undisturbed segments was determined as reference. Based on this, the efficiency in different types of intersections was computed per cyclist group. It turned out that infrastructural aspects, cyclist group and the presence and behaviour of interacting traffic influenced cyclist efficiency. Faster cyclists were delayed more when the infrastructure required a stop regardless of the traffic situation, like at a red traffic light or a stop sign. The members of the so-called ‘comfort cyclists’ group were delayed the most in a roundabout with mixed traffic, where many chose to get off their bike and walk. In a society working for equality of access to the transport system, it is recommended to develop solutions that consider and accommodate the behaviours of different cyclist groups when planning bicycling infrastructure.
48.	Kircher, Katja, 1973-, et al. (författare) Design and analysis of semi-controlled studies 2017 Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 46:B, s. 404-412 Tidskriftsartikel (refereegranskat)abstract Semi-controlled studies provide a hybrid approach in between controlled experiments and naturalistic driving studies. As in controlled experiments, the researcher can assign participants to groups, select the route and define the tasks, but the participants are given more freedom when it comes to if, when, where and how to perform the tasks. Increased flexibility makes it possible to investigate how drivers use tactical behaviour to accommodate task execution. The disadvantage is decreased control and more complicated analyses.The main objective of this paper is to discuss how to analyse data obtained in semi-controlled studies.The analysis of data from a semi-controlled study include three types of variables:variables that describe the experimental designvariables that describe the tactical choices of the participantsoperational variables such as speed, lateral position or glance behaviourTo analyse the three types of variables a two-step procedure is suggested. First, the tactical indicators are analysed with regard to the experimental design. Second, the operational indicators are analysed and the tactical indicators are used to divide participants into sub-populations.The semi-controlled design does not need any new statistical procedures to be developed. It is more important that the analysis conditions on the initial properties and not on structures that happen to occur during the experiment, like where the participant chose to do a certain task.We recommend to use the semi-controlled study method when investigating questions involving adaptive and compensatory behaviour on the tactical level. It is especially useful if causal relationships are of interest, if the data collection should be accelerated in comparison to naturalistic studies, and if certain geographical locations definitely should be included.
49.	Kircher, Katja, 1973-, et al. (författare) Tactical steering behaviour under irrevocable visual occlusion 2018 Ingår i: Transportation Research Part F. - : ELSEVIER SCI LTD. - 1369-8478 .- 1873-5517. ; 55, s. 67-77 Tidskriftsartikel (refereegranskat)abstract Objective: To investigate the extent of a driver's mental model with irrevocable visual occlusion and analysing the distance to crash.Background: Drivers have a mental model of the immediate surroundings which allows them to predict their own as well as others' travel paths. To navigate safely through traffic, this mental model has to be updated frequently to remain valid. In between information sampling events, the mental model will become outdated over time, as the traffic system is dynamic.Method: A simulator study with 22 participants was conducted to investigate the information decay in the mental model. This was implemented by extending visual occlusion until the driver collided with another vehicle or ran off the road, thus providing an estimate of how long it takes until the mental model becomes obsolete.Results: An analysis of variance with the factors curve direction, curve radius and traffic showed that curve radius did not influence the distance to crash. Without traffic, drivers veered off the road sooner in right curves. Adding traffic eliminated this difference. Traffic ahead led to a shortened distance to crash. Compared to a tangential travel path from the current lateral position at the time of the occlusion, drivers crashed on average 2.6 times later than they would have, had they not had any mental model of the situation.Conclusions: The drivers' mental representation of the future situation seems to include information on how to act, to alleviate deviations in yaw angle, including and considering the presence of other road users.
50.	Kircher, Katja, 1973-, et al. (författare) The role of group membership in active road user attention across different age groups 2023 Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 97, s. 314-327 Tidskriftsartikel (refereegranskat)abstract This study aimed to explore how travelling in different group constellations (alone, with known or with unknown people) affects children's and adults’ visual behaviour in traffic when cycling or walking. Additionally, mobile phone/earphone usage was considered, too. A follow-along study (n = 43) and an observation study (n = 898) were conducted to observe travellers in a natural setting. In the follow-along study, eye-tracking was used to investigate children's glances behaviour on their way to school and how well they manage to fulfil attentional requirements. The observational study focused on children's and adults' visual behaviour at several intersections. The main result of the study was that group membership appears to have a large influence on individuals' visual sampling strategy. In formal groups reliance on each other was found to be stronger than in informal groups. People with a natural responsibility in the group, such as parents or other adults, take a more active role in visual monitoring. Reliance on others is found to a greater extent among pedestrians than cyclists. Regarding communication devices, the use of earphones did not significantly affect glance behaviour towards relevant areas. In naturalistic situations, group constellation, age and phone/earphone usage are interlinked, which needs to be considered when studying these factors.

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