Naturalistic driving study for older drivers based on the DriveSafe app

2019 IEEE Intelligent Transportation Systems Conference (ITSC), Auckland, New Zealand, 27-30 Oct. 2019Elderly population is increasing year after year in the developed countries. However, the knowledge of actual mobility needs of senior drivers is scarce. In this paper, we present a naturalistic driving study (NDS) focused on older drivers through smartphone technology and using our DriveSafe app. Our system automatically generates a driving analysis report based on objective indicators. The proposal supposes an improvement over the traditional surveys and observers, and represents an advance over the current NDSs by using smartphones instead of complex instrumented vehicles. Our method avoids the problems of manual annotation by using an automatic method for data reduction information. Furthermore, a comparison between traditional questionnaires and information provided by our system is carried out and conclusions are presented.Ministerio de Economía y CompetitividadDGTComunidad de Madri

Shareable Driving Style Learning and Analysis with a Hierarchical Latent Model

Driving style is usually used to characterize driving behavior for a driver or a group of drivers. However, it remains unclear how one individual's driving style shares certain common grounds with other drivers. Our insight is that driving behavior is a sequence of responses to the weighted mixture of latent driving styles that are shareable within and between individuals. To this end, this paper develops a hierarchical latent model to learn the relationship between driving behavior and driving styles. We first propose a fragment-based approach to represent complex sequential driving behavior, allowing for sufficiently representing driving behavior in a low-dimension feature space. Then, we provide an analytical formulation for the interaction of driving behavior and shareable driving style with a hierarchical latent model by introducing the mechanism of Dirichlet allocation. Our developed model is finally validated and verified with 100 drivers in naturalistic driving settings with urban and highways. Experimental results reveal that individuals share driving styles within and between them. We also analyzed the influence of personalities (e.g., age, gender, and driving experience) on driving styles and found that a naturally aggressive driver would not always keep driving aggressively (i.e., could behave calmly sometimes) but with a higher proportion of aggressiveness than other types of drivers

Making Sense of Making Sense - Exploring users’ understanding of automated vehicles during use

Automation has for a long time been embraced by the vehicle industry and in recent years, the amount and sophistication of automation in vehicles have rapidly increased, creating more advanced automated vehicle (AV) systems. The complexity of AVs does not only pose a technical challenge, but the entry of automation into vehicles also creates new dynamics in the human-vehicle interaction, that puts new demands on the user. Previous research has identified the importance of user understanding of Automated Vehicles, as this affects usage directly as well as indirectly by impacting acceptance. In this thesis, a design approach has been chosen that uses a product semantic framework as the basis for addressing the issue of user understanding with the aim of exploring how users make sense of the AV. The research presented is based on data from three quasi-experimental study, conducted with users of a (i) seemingly fully automated vehicle, (ii) vehicle with two different levels of automation, and (iii) an advanced driver assistance system for docking buses. The findings show that use of the AVs gave rise to several levels of meaning, based on two different processes. The main one was an intermeaning process, where integration of the participants’ conceptual models, artefactual signifiers, and situational signifiers in a context developed meaning. However, an intrameaning process was also evident, where meanings themselves developed new meanings. The findings also show that the usage of the AV itself is an integral part of the process of making sense, where both processes affect how the system is used and the usage triggers new meaning to arise. This thesis presents a model based on the findings, describing four important factors: the user’s conceptual model, the signifiers, the meanings that arise during use of the AV, and the context in which it is used. The model illustrates the complex interplay between these four components and can be used to better understand and investigate how users make sense of AVs to aid the design and development of AVs. The thesis also contributes to the field of product semantics through the practical application of product semantic theories, in addition to providing further insight into how users develop meaning and make sense of artefacts, by describing the processes and components which seem to be the foundation when making sense of artefacts.Having said that, further studies need to explore in greater detail the dynamics of the process of making sense, how meaning changes during a prolonged usage, and how the tentative model could be advanced to be able to be used in the AV development and evaluation processes

Investigating the transition from normal driving to safety-critical scenarios

Investigation of the correlation between factors associated with crash development has enabled the implementation of methods aiming to avert and control crash causation at various points within the crash sequence (Evans, 2006). Partitioning the crash sequence is important because intricated crash causation sequences can be deconstructed and effective prevention strategies can be suggested (Wu & Thor, 2015). Towards this purpose, Tingvall et al. (2009) documented the so-called integrated safety chain which described the change of crash risk on the basis of a developing sequence of events that led to a collision. This thesis examines the crash sequence development and thus, the transition from normal driving to safety critical scenarios. [Continues.

The Impact of Sleepiness and Sleep Constructs on Driving Performance

Sleepiness causes performance decrements that lead to thousands of crashes and fatalities annually. Research supports the conclusions that sleep duration and circadian rhythms impact sleepiness and affect driving performance. Conflicting in the literature is whether severity of sleep disorders, sleep quality and subjective sleepiness affect driving performance. The correlation between a driver\u27s perception of their sleepiness and their driving performance is also unclear. The primary goal of this study was to create an in-depth model demonstrating which measures of sleepiness influence driving performance. It was hypothesized that sleep quality, sleep apnea severity and subjective sleepiness add to a model of how sleep constructs impact driving performance. The secondary goal of this study was to compare trait and state sleepiness to determine which correlates with driving performance. It was hypothesized that participants with state sleepiness would have a greater decline across the 60-minute drive as compared to participants with trait sleepiness. Both sleepiness groups would have increased lane position variability compared to the normal group. The tertiary goal was to examine driving performance decrements of sleep apnea drivers compared with healthy controls. It was hypothesized that the sleep apnea group would perform worse on the driving simulator test compared with the control group. Results indicate that sleep quality and subjective trait sleepiness significantly add to models of sleepiness and driving performance. The model developed here show that years with driver\u27s license, sleep efficiency and trait sleepiness are significant predictors of lane position variability. Also, results show that driving performance is worse for participants high in trait sleepiness. Participants with high state sleepiness had no significant performance differences compared to non-sleepy participants. Sleep apnea participants did not perform significantly worse than controls as hypothesized but there was a significant group by time interaction indicating that sleep apnea participants\u27 performance degraded more quickly over the course of the drive. These results can be generalized to the community members and students, but not necessarily to sleep disorder center patients