Designing Auditory Warning Signals to Improve the Safety of Commercial Vehicles

Based on four studies, this thesis aims to explore how to design auditory warning signals that can facilitate safer driving by operators of heavy goods vehicles. The first three studies focus on the relationships between certain characteristics of auditory warnings and various indicators of traffic safety. A deeper understanding of these relationships would allow system developers to design auditory signals that are better optimised for safety. The fourth study examines the opinions of both vehicle developers and professional drivers regarding warning attributes. One major conclusion is that meaningful warning sounds that are related to the critical event can improve safety. As compared with arbitrarily mapped sounds, meaningful sounds are easier to learn, can improve drivers’ situation awareness, and generate less interference and less annoyance. The present thesis also supports the view that commercial drivers’ initial acceptance of these sounds may be very high. Annoyance is an especially important aspect of warning design to consider; it can negatively influence driving performance and may lead drivers to turn off their warning systems. This research supports the notion that drivers do not consider that negative experience is an appropriate attribute of auditory warnings designed to increase their situation awareness. Also, commercial drivers seem to report, significantly more than vehicle developers, that having less-annoying auditory warnings is important in high-urgency driving situations. Furthermore, the studies presented in this thesis indicate that annoyance cannot be predicted based on the physical properties of the warning alone. Learned meaning, appropriateness of the mapping between a warning and a critical event, and individual differences between drivers may also significantly influence levels of annoyance. Arousal has been identified as an important component of driver reactions to auditory warnings. However, high levels of arousal can lead to a narrowing of attention, which would be suboptimal for critical situations during which drivers need to focus on several ongoing traffic events. The present work supports the notion that high-urgency warnings can influence commercial drivers’ responses to unexpected peripheral events (i.e., those that are unrelated to the warning) in terms of response force, but not necessarily in terms of response time. The types of auditory warnings that will be developed for future vehicles depend not only on advances in research, but also on the opinions of developers and drivers. The present research shows that both vehicle developers and drivers are aware of several of the potentially important characteristics of auditory warnings. For example, they both recognise that warnings should be easy to understand. However, they do disagree regarding certain attributes of warnings, and, furthermore, developers may tend to employ a “better safe than sorry” strategy (by neglecting factors concerning annoyance and the elicitation of severe startled responses) when designing high-urgency warnings. Developers’ recognition of the potentially important attributes of auditory warnings should positively influence the future development of in-vehicle systems. However, considering the current state of research regarding in-vehicle warnings, it remains challenging to predict the most suitable sounds for specific warning functions. One recommendation is to develop a design process that examines the appropriateness of in-vehicle auditory warnings. This thesis suggests an initial version of such a process, which in this case was produced in collaboration with system designers working in the automotive industry

Human-centred design of clinical auditory alarms

Auditory alarms are commonly badly designed, providing little to no information or guidance. In the healthcare context, the poor acoustics of alarms is one contributor for the noise problem. The goal of this thesis is to propose a human-centred methodology for the design of clinical auditory alarms, by making them less disruptive and more informative, thus improving the healthcare soundscape. It implements this methodology from concept to evaluation and validation, combining psychoacoustics with usability and user experience methods. Another aim of this research consisted in understanding the limitations and possibilities offered by online tools for scientific studies. Thus, different processes and methodologies were implemented, and corresponding results were discussed. To understand the acoustic healthcare environment, field visits, interviews, and surveys were performed with healthcare professionals. Additionally, sound pressure levels and frequency analysis of several surgeries in different hospitals provided specific sound design requirements, which were added to an existent body of knowledge on clinical alarm design. A second stage consisted in prototyping very simple sounds to comprehend which temporal and spectral parameters of sound could be manipulated to communicate clinical information. Parameters such as frequency, speed, onset, and rhythm were studied, and relations between subjective perception and physical parameters were established. In parallel, and heavily influenced by the new IEC 60601-1-8 - General requirements, tests and guidance for alarm systems in medical electrical equipment and medical electrical systems, a design strategy with auditory icons was created. This strategy intended to provide as much information as possible in an auditory alarm. To do so, it involved two main components: a priority pointer indicating the priority of the alarm; an auditory icon indicating the cause of the alarm. A third component indicating increasing or decreasing tendency of the vital sign was designed, but not validated with users. After online validation of the priority pointer and auditory icon for eight categories (cardiac, drug administration, ventilation, blood pressure, perfusion, oxygen, temperature, and power down), a new library of clinical auditory alarms is proposed.Os alarmes auditivos são habitualmente mal concebidos, dando poucas informações ou orientações perante a situação que despoletou o aviso. No contexto da saúde, a má acústica dos alarmes é um dos contribuidores para o problema do ruído. O objetivo desta tese é o de melhorar a paisagem sonora em ambientes clínicos, propondo uma metodologia centrada no Humano para o design de alarmes auditivos clínicos, tornando-os menos disruptivos e mais informativos. Essa metodologia é implementada desde o conceito até a avaliação e validação, combinando métodos da psicoacústica com métodos de usabilidade e experiência do utilizador. Outro objetivo desta investigação é o de compreender as limitações e possibilidades oferecidas pelas ferramentas online para estudos científicos. Assim, diversos processos e metodologias foram implementados, e os respetivos resultados são discutidos. Para compreender o ambiente acústico clínico, foram realizadas visitas de campo, entrevistas e inquéritos com profissionais de saúde. Além disso, avaliou-se o nível de pressão sonora e frequências de várias cirurgias em diferentes hospitais. Esta atividade forneceu requisitos específicos de design de som que foram adicionados a um corpo existente de conhecimento sobre design de alarmes clínicos. Uma segunda etapa consistiu na prototipagem de sons simples para compreender que parâmetros temporais e espectrais do som poderiam ser manipulados para comunicar informações clínicas. Parâmetros como frequência, velocidade, envelope e ritmo foram estudados, e as relações entre a perceção subjetiva e os parâmetros físicos foram estabelecidas. Paralelamente, e fortemente influenciado pela nova norma IEC 60601-1-8 - Requisitos gerais, testes e orientações para sistemas de alarme em equipamentos médicos elétricos e sistemas médicos elétricos, foi criada uma estratégia de design com ícones auditivos. Essa estratégia pretendia incorporar o máximo de informações num alarme auditivo. Para isso, envolveu dois componentes principais: um ponteiro de prioridade que indica a prioridade do alarme; e um ícone auditivo que indica a causa do alarme. Um terceiro componente de tendência (aumento ou diminuição do valor do sinal vital) foi criado, mas não validado com utilizadores. Após a validação do ponteiro de prioridade e ícone auditivo para oito categorias (cardíaco, administração de medicamentos, ventilação, pressão arterial, perfusão, oxigénio, temperatura e falha de equipamento), propõe-se uma nova biblioteca de alarmes auditivos clínicos

The Recognizability and Localizability of Auditory Alarms: Setting Global Medical Device Standards.

Objective Four sets of eight audible alarms matching the functions specified in IEC 60601-1-8 were designed using known principles from auditory cognition with the intention that they would be more recognizable and localizable than those currently specified in the standard. Background The audible alarms associated with IEC 60601-1-8, a global medical device standard, are known to be difficult to learn and retain, and there have been many calls to update them. There are known principles of design and cognition that might form the basis of more readily recognizable alarms. There is also scope for improvement in the localizability of the existing alarms. Method Four alternative sets of alarms matched to the functions specified in IEC 60601-1-8 were tested for recognizability and localizability and compared with the alarms currently specified in the standard. Results With a single exception, all prototype sets of alarms outperformed the current IEC set on both recognizability and localizability. Within the prototype sets, auditory icons were the most easily recognized, but the other sets, using word rhythms and simple acoustic metaphors, were also more easily recognized than the current alarms. With the exception of one set, all prototype sets were also easier to localize. Conclusion Known auditory cognition and perception principles were successfully applied to an existing audible alarm problem. Application This work constitutes the first (benchmarking) phase of replacing the alarms currently specified in the standard. The design principles used for each set demonstrate the relative ease with which different alarm types can be recognized and localized

Human-Machine Interface Development For Modifying Driver Lane Change Behavior In Manual, Automated, And Shared Control Automated Driving

Rear-end crashes are common on U.S. roads. Driver assistance and automated driving technologies can reduce rear-end crashes (among other crash types as well). Braking is assumed for forward collision warning (FCW) and automatic emergency braking (AEB) systems. Braking is also used for adaptive cruise control (ACC) and in automated driving systems more generally. However, steering may be advised in an emergency if the adjacent lane is clear and braking is unlikely to avoid a collision. Steering around an obstacle when feasible also eliminates the risk of becoming the new forward collision hazard. Driver assist technology like emergency steer assist (ESA) and Level 2 or Level 3 automated driving systems might facilitate manual emergency lane changes but may require the driver to manually initiate the maneuver, something which drivers are often reluctant to do. An Human-Machine Interface (HMI) might advise the driver of a steerable path when feasible in forward collision hazard situations. Such an HMI might also advise a driver of normal lane change opportunities that can reduce travel time, increase fuel efficiency, or simply enhance the driving experience by promoting `flow.\u27 This dissertation investigated the propensity of drivers to brake only versus steer in both manual and automated driving situations that end in a high-intensity forward collision hazard. A audio-visual Field of Safe Travel (FOST) cluster display and haptic steering wheel HMI were developed to advise drivers in both discretionary and emergency situations of a lane change opportunity. The HMI was tested in a moving base simulator in manual driving, in fully autonomous driving, and in shared-control autonomous driving during a simulated highway commute that ended in an high-intensity forward collision hazard situation. Results indicated that a) driver response was affected by the nature of the automated driving (faster response in hands-on shared control versus hands-off fully autonomous driving); b) exposure to the HMI in normal lane changes both familiarized the driver with the HMI and introduced a mental set that steering was also a possibility rather than braking only; c) but that drivers used their direct vision to determine their response in the emergency event. A methodological issue related to mental set was also uncovered and resolved through screening studies. The final study brought the dissertation full-circle, comparing hands-off fully automated driving to hands-on shared control automated driving in the context of either providing some or no exposure to the developed LCA system concept. Results of the final study indicated that shared control lies somewhere between that of manual driving and hands-off fully automate driving. Benefits were also shown to exist for the LCA system concept irrespective of whether the discrete haptic profiles are included or not. The discrete haptic profiles did not statistically reliably increase response times to the FC hazard event, although they do show a trend toward decreasing response variability. This finding solidified the fact that by implementing a system for benign driving that aids in establishing a mental set to steer around an obstacle may actually be beneficial for rear-end crash scenarios. This dissertation’s contributions include a) audio-visual FOST display concepts; b) discrete haptic steering display concepts; c) a paired-comparisons scaling for urgency for haptic displays applied while driving; d) a new ``mirage scenario\u27\u27 methodology for eliciting subjective assessments in the context of a forward collision hazard, briefly presented then removed, without risk of simulator sickness, and e) a methodological lesson for others who wish to investigate semi-automated and automated driving interventions and must manage driver mental set carefully

Traffic Information Signs, Colour Scheme of Emergency Exit Portals and Acoustic Systems for Road Tunnel Emergency Evacuations

This work presents a literature review and a questionnaire study with 62 participants aimed at providing recommendations on the design of a set of evacuation systems for road tunnels: 1) Traffic Information Sign (TIS) - message and size of the sign (large or small), colour scheme, and use of pictograms and/or flashing lights, 2) Emergency exit portal layout - colour scheme, 3) Acoustic systems - voice message and/or warning signals. The TIS is recommended to include the use of two panels which present text (in amber) and flashing lights in one panel and the emergency exit pictorial symbol in green in the other panel. An increased size of the panels has a positive effect on capturing participants’ attention. The recommended colour scheme for the emergency exit portal is safety green for the portal and a “green darker than the safety green” for the door. Vocal messages are not recommended since they may be quite difficult to perceive in tunnels. The use of a warning signal (F_SAW signal) based on British Standards is recommended

Warning a Distracted Driver: Smart Phone Applications, Informative Warnings and Automated Driving Take-Over Requests

abstract: While various collision warning studies in driving have been conducted, only a handful of studies have investigated the effectiveness of warnings with a distracted driver. Across four experiments, the present study aimed to understand the apparent gap in the literature of distracted drivers and warning effectiveness, specifically by studying various warnings presented to drivers while they were operating a smart phone. Experiment One attempted to understand which smart phone tasks, (text vs image) or (self-paced vs other-paced) are the most distracting to a driver. Experiment Two compared the effectiveness of different smartphone based applications (app’s) for mitigating driver distraction. Experiment Three investigated the effects of informative auditory and tactile warnings which were designed to convey directional information to a distracted driver (moving towards or away). Lastly, Experiment Four extended the research into the area of autonomous driving by investigating the effectiveness of different auditory take-over request signals. Novel to both Experiment Three and Four was that the warnings were delivered from the source of the distraction (i.e., by either the sound triggered at the smart phone location or through a vibration given on the wrist of the hand holding the smart phone). This warning placement was an attempt to break the driver’s attentional focus on their smart phone and understand how to best re-orient the driver in order to improve the driver’s situational awareness (SA). The overall goal was to explore these novel methods of improved SA so drivers may more quickly and appropriately respond to a critical event.Dissertation/ThesisDoctoral Dissertation Applied Psychology 201

Auditory alert for in-vehicle safety technologies: a review

Safety technology has evolved rapidly in the past few years to become much more driver-aware and automatic. Many of these technologies build upon one another in a good, better, best pattern to provide the safest possible driving experience. It is expected that this system can eliminate or mitigate road accidents due to reckless and careless driving. However, safety or driver-assistance features are no substitute for the driver's responsibility to operate safely. A survey revealed that the warning alarms were turned off by 70% of drivers due to annoying audio characteristics. It is vital to consider frustration linked to an alarm, where it can affect the driver's behavior. It is recommended to identify optimum chime sound characteristics for the driver’s alert and respond appropriately to improve the effectiveness of the auditory signal. In this paper, a review on the identification of the type of warning modality, frequency setting, and warning priority for vehicle safety features technology from the selected vehicle manufacturers are explained