Auditory Warning Research Articles

Effects of integrated takeover request warning with personal portable device on takeover time and post-takeover performance in level 3 driving automation

Introduction: Level 3 driving automation defined by the Society of Automotive Engineers (SAE) requests human drivers to drive manually when the vehicle cannot perform the driving task. In this regard, researchers have studied the integrated takeover request (TOR) which provides visual and auditory TOR warning in both vehicle interface (e.g., dashboard, windshield (head-up display) and personal portable device (PPD) (e.g., cell phone, tablet). However, these studies neither used auditory TOR warning in PPD nor examined the effect of use of headphone on takeover. Thus, this study evaluates the effects of the integrated TOR with the use of headphones on the takeover time and the post-takeover performance. Method: The behavior of 60 drivers was observed in the driving simulator experiment. During the experiment, the drivers watched a video on a tablet in automated driving, received the TOR warning, and manually drove in the lane change and pullover scenarios. The survey was also conducted to ask drivers’ experience and preference for TOR warning. Results: The integrated TOR significantly reduced the takeover time compared to the conventional TOR which provides the TOR warning in vehicle interface only. The integrated TOR also improved the post-takeover performance as indicated by more stable steering operation and safer driving behavior after TOR warning. However, the use of headphones did not significantly reduce the takeover time or improve the post-takeover performance for the integrated TOR. The participants generally perceived higher subjective comfort and safety level with the integrated TOR than the conventional TOR. Conclusions: The integrated TOR with auditory warning in PPD can significantly reduce the takeover time and improve the post-takeover performance in both urgent and less urgent conditions. Practical applications: The integrated TOR with auditory warning in PPD can be applied to SAE Level 3 driving automation for safe transition from automated to manual driving.

Effectiveness of alarm sounds in preventing operator habituation to auditory warnings in construction equipment

A proximity auditory warning (AW) system has been developed to mitigate accidents involving construction equipment blind spots. However, frequent AW sounds can lead to habituation among construction equipment operators, potentially reducing the system's effectiveness. This paper assessed the effectiveness of AW sounds in mitigating habituation. Twenty-one participants underwent a driving simulation, with reaction time and skin conductance level used as indicators of habituation. Participants' responses to the conventional probe-tone sound were compared with three proposed AW sounds: an auditory icon resembling a threat or dangerous situation, a self-owned name (SON) addressing the participant's name, and a combination of both. SON is recommended as a viable alternative for effective alarm sound. By investigating alarm sounds that enhance operators' responsiveness to obstacles in blind spots, particularly in environments where frequent alarms are unavoidable, this paper contributes to reducing struck-by accidents involving construction equipment.

Measuring Habituation to Auditory Warnings Using Behavioral and Physiological Data

Measuring Habituation to Auditory Warnings Using Behavioral and Physiological Data

Effects of looming audio on transcranial magnetic stimulation-induced phosphene perception.

Looming sounds are known to influence visual function in the brain, even as early as the primary visual cortex. However, despite evidence that looming sounds have a larger impact on cortical excitability than stationary sounds, the influence of varying looming strengths on visual ability remains unclear. Here, we aim to understand how these signals influence low-level visual function. Fourteen healthy undergraduate students participated. They were blindfolded and received transcranial magnetic stimulation (TMS) to the primary visual cortex following auditory stimulation with different strength looming sounds. Participants reported whether they perceived a phosphene, or an illusory visual percept, following TMS stimulation. We hypothesized that rates of phosphene activity would increase with increasing levels of looming strength. A linear mixed-effect model showed that phosphene activity was significantly higher at higher strength of looming (F(1, 69) = 5.33, p = .024) and at higher TMS pulse strength (F(1, 18) = 4.71, p = .043). However, there was also a significant interaction between looming strength and pulse strength (F(1, 69) = 4.33, p = .041). At lower levels of TMS strength, phosphene rate increased with looming strength, while at higher levels of TMS strength the effect was reversed. These results suggest a complex relationship between looming strength and cortical activity, potentially reflecting the mixed contribution of total auditory energy and the rate of changes. This work will enhance our ability to predict audiovisual interactions and may help improve auditory warning systems designed to capture visual attention.

Effects of visual and auditory warnings during driving on mental workload

Effects of visual and auditory warnings during driving on mental workload

Psychological evaluation of auditory warning signal for train horn

Air horns are commonly used to signal danger or caution during railroad operations. The main objectives of those auditory signals (i.e., whistle cords) are to "warn of danger," "call attention," and "notification of approach" in the situation before an accident occurs or "report an emergency" to those around after an accident occurs. Further, in case of using auditory signals in nonemergency situations (e.g., during the departure or arrival of a train), loud or unpleasant sounds should be avoided to the greatest possible extent, considering noise pollution in the environment. This study examined the nature of auditory signals for railroad vehicles through psycho-acoustic experiments using 11 types of auditory stimuli, including a "short, rapid horn sound" and a "long, slow horn sound." In the rating experiments, the auditory stimuli were presented via headphones to individual participants. The results indicated that upon initiating the auditory signal with an electronic horn sound (less unpleasant and dangerous impression) before blowing the air horn to alert perceived danger, the impressions of "warning," "caution," and "danger" tended to decrease, whereas those of "pleasantness," "quietness," and "relaxedness" tended to increase. The combined usage of electric and air horns can effectively provide auditory signals for maintaining the safety of railroad operations while addressing the associated noise pollution.

<b>Designing Auditory Warnings for Preventing Arousal-level Decline during Train Operation and Examining Its Effectiveness</b>

<b>Designing Auditory Warnings for Preventing Arousal-level Decline during Train Operation and Examining Its Effectiveness</b>

Are Warnings Suitable for Presentation in Head-Up Display? A Meta-Analysis for the Effect of Head-Up Display Warning on Driving Performance

Head-up display (HUD) warnings are gaining increasing attention with the growing importance of advanced warning systems in vehicles for improving driving safety. However, the effectiveness of HUD warnings is still controversial considering the various driving performance indexes, warning modalities, and driving scenarios used in previous studies. This study conducts meta-analyses of the relevant literature to examine whether HUD warnings (both unimodal HUD warnings and multimodal warnings with HUD) have advantages compared with other warnings (head-down display warnings, auditory warnings, tactile warnings, and multimodal warnings without HUD) for driver reaction times and driving quality. Overall, 33 articles were included in four meta-analyses. Additionally, the effects of the related moderator variables of scenario, mapping of warnings, and non-driving-related tasks (NDRTs) on the relationship between using HUD warnings and using non-HUD warnings was analyzed. The results show that using unimodal HUD warnings leads to faster reaction times compared with head-down display warnings but has no significant advantage on driving performance over auditory warnings in general and results in slower reaction times than using tactile warnings. However, results of the moderating effects suggest that using HUD warnings in non-critical scenarios and using high mapping HUD icons (i.e., HUD warnings with specific hazard information) are conducive to improving driving performance in comparison with other warning types. These results highlight the potential advantages of HUD in transmitting warning information. The future application and design of HUD warnings may need to focus on specific situations considering iconic mapping to an event.

Looming sounds as auditory warnings: Uses for enhancing visual contrast sensitivity?

Looming sounds have been shown to influence visual perception, suggesting they may make effective auditory warning tones for use with visual tasks. To explore the use of looming sounds as warning signals and to determine whether the strength of a looming sound will impact its effectiveness, we tested five looming sounds with different amplitude increases as warning tones in a contrast sensitivity task where participants made judgements concerning the orientation of low-contrast sinusoidal gratings. Reaction time, accuracy, and contrast threshold were measured for each sound condition. Our results indicate that accuracy was higher and reaction time was faster when a sound was present compared to when no sound was present, and contrast threshold was significantly lowered in sound trials compared to silent trials. However, there was no difference in accuracy, reaction time, or contrast threshold by strength of looming. These results suggest that while auditory warning sounds do enhance performance on a basic visual task, the benefit was not unique to looming sounds. This experiment will help inform the design of warnings by providing insight into the underlying effects of looming sounds on visual performance.

Foreseeing interruptions in dynamic environments may undermine the adequacy between perceived and observable task performance

ABSTRACT The negative impact of interruptions on performance can sometimes be mitigated by notifying individuals shortly before their task is suspended. However, little is known about the accuracy with which individuals can assess the consequences of both unexpected and anticipated interruptions. This study investigated how suspending a dynamic task with or without prior warning influenced individuals’ self-reported performance and workload, and whether their perception aligned with their observable performance. Participants completed a simulation of above-water warfare in which they classified the threat level of surrounding aircraft and neutralized hostile aircraft. Subjective (performance, workload) and behavioural (performance) measures were compared across three types of scenarios: uninterrupted, unexpectedly interrupted, or interrupted following an auditory warning. Nearly all behavioural performance indicators were impaired by interruptions. Although the warning only partially mitigated this negative impact, participants perceived it as an effective aid overall. Therefore, individuals may sometimes misperceive that forewarned interruptions help overcoming performance costs.

Is Users’ Trust during Automated Driving Different When Using an Ambient Light HMI, Compared to an Auditory HMI?

The aim of this study was to compare the success of two different Human Machine Interfaces (HMIs) in attracting drivers’ attention when they were engaged in a Non-Driving-Related Task (NDRT) during SAE Level 3 driving. We also assessed the value of each on drivers’ perceived safety and trust. A driving simulator experiment was used to investigate drivers’ response to a non-safety-critical transition of control and five cut-in events (one hard; deceleration of 2.4 m/s2, and 4 subtle; deceleration of ~1.16 m/s2) over the course of the automated drive. The experiment used two types of HMI to trigger a takeover request (TOR): one Light-band display that flashed whenever the drivers needed to takeover control; and one auditory warning. Results showed that drivers’ levels of trust in automation were similar for both HMI conditions, in all scenarios, except during a hard cut-in event. Regarding the HMI’s capabilities to support a takeover process, the study found no differences in drivers’ takeover performance or overall gaze distribution. However, with the Light-band HMI, drivers were more likely to focus their attention to the road centre first after a takeover request. Although a high proportion of glances towards the dashboard of the vehicle was seen for both HMIs during the takeover process, the value of these ambient lighting signals for conveying automation status and takeover messages may be useful to help drivers direct their visual attention to the most suitable area after a takeover, such as the forward roadway.

Effects of collision warning characteristics on driving behaviors and safety in connected vehicle environments

With the emerging connected vehicle (CV) technologies, a novel in-vehicle omni-direction collision warning system (OCWS) is developed. For example, vehicles approaching from different directions can be detected, and advanced collision warnings caused by vehicles approaching from different directions can be provided. Effectiveness of OCWS in reducing crash and injury related to forward, rear-end and lateral collision is recognized. However, it is rare that the effects of collision warning characteristics including collision types and warning types on micro-level driver behaviors and safety performance is assessed. In this study, variations in drivers’ responses among different collision types and between visual only and visual plus auditory warnings are examined. In addition, moderating effects by driver characteristics including drivers’ demographics, years of driving experience, and annual driving distance are also considered. An in-vehicle human–machine interface (HMI) that can provide both visual and auditory warnings for forward, rear-end, and lateral collisions is installed on an instrumented vehicle. 51 drivers participate in the field tests. Performance indicators including relative speed change, time taken to accelerate/decelerate, and maximum lateral displacement are adopted to reflect drivers’ responses to collision warnings. Then, generalized estimation equation (GEE) approach is applied to examine the effects of drivers’ characteristics, collision type, warning type and their interaction on the driving performance. Results indicate that age, year of driving experience, collision type, and warning type can affect the driving performance. Findings should be indicative to the optimal design of in-vehicle HMI and thresholds for the activation of collision warnings that can increase the drivers’ awareness to collision warnings from different directions. Also, implementation of HMI can be customized with respect to individual driver characteristics.

Eye-movement indices of arousal predict ADHD and comorbid externalizing symptoms over a 2-year period

Attention-deficit/hyperactivity disorder (ADHD) follows a variable course across childhood. Disrupted arousal has been hypothesized to underlie core symptoms as well as comorbid internalizing and externalizing conditions. The current study examined eye-movement and pupil-dilation metrics indexing arousal as longitudinal predictors of ADHD, externalizing, and internalizing symptoms over a 2-year period. Participants aged 8–13 years (N = 54, 30% with a diagnosis of ADHD) completed a modified version of the gap-overlap task including arousal-inducing auditory warning signals. Parents rated symptoms at the time of testing and at 2 years follow-up. Phasic alerting (reaction-time reduction after alerting cues) is an index of arousal. Here, larger phasic alerting effects predicted higher ADHD-symptom levels 2 years later. Blunted pupil-dilation responses predicted externalizing symptoms at T2, controlling for ADHD and externalizing at T1. Our results support the theory that ADHD is associated with altered arousal. Blunted arousal reactivity may be a longitudinal risk factor for externalizing problems in children with ADHD symptoms.

The Effectiveness of an Intelligent Speed Assistance System with Real-Time Speeding Interventions for Truck Drivers: A Belgian Simulator Study

Speeding is one of the leading risk factors in road safety. Not only is it one of the leading causes of accidents, but it also has an extensive effect on the impact and consequences of accidents. This is especially the case for trucks, where the enforced speed limit is often dependent on local legislation and context rather than speed limit traffic signs. This study is part of the greater i-DREAMS project and aims to explore the effectiveness of an intelligent speed assistance system for truck drivers on different road types. To achieve this, a simulator experiment was performed with 34 professional truck drivers in Belgium. Participants first made a baseline drive, followed by two more drives, where they received visual information about the enforced speed limit but also visual and auditory warnings when exceeding the speed limit. The drives included different road environments with different speed limits. The results reveal a significant reduction in relevant parameters (i.e., average speed, minimum speed, maximum speed, and percentage of distance above the speed limit) when drivers received information and warnings about speeding while driving on a rural 1 × 1 road with a speed limit of 70 km/h (60 km/h for trucks). Further research is needed to validate this effect on other road types and under more-challenging conditions.

The Effectiveness of Virtual Fencing of Bull Calves in a Holistic Grazing System

Large grazers are essential for nature conservation. In order to prevent grazers from moving to unintended areas, it may be necessary to keep them inside enclosures. Physical fences present a number of problems, such as fragmenting the landscape. Virtual fencing, however, is a possible replacement for physical fencing, making it possible to enclose grazers without physical boundaries. Virtual fencing systems utilise collars with GPS technology to track animals and deliver auditory warnings and electric impulses to keep animals within predefined boundaries. This study examines how effective the virtual fencing system Nofence© is at enclosing calves in a holistically managed setting. Holistic management is a rotational grazing technique where an enclosure is grazed in small strips at a time. It is investigated whether the calves become habituated to the virtual fence and whether there is a correlation between the number of warnings received by every two calves in order to explore potential herd behaviour. Finally, this study examines which calves interact the most with the virtual fence by investigating the relationship between physical activity and number of interactions. Seventeen calves were fitted with a GPS collar from the company Nofence© and placed in a holistically managed enclosure. Data were gathered from 4 July to 30 September 2022. The study found that virtual fence was able to contain calves inside the designated enclosure, and over time the calves received notably fewer electrical impulses compared to auditory warnings. The results of Pearson's correlation between auditory warnings received by two random calves were inconclusive, but the use of a sliding window analysis should be further explored. Lastly, the most physically active animals were the ones who received the most auditory warnings, but they did not receive more impulses. No significant correlation was found between the number of electric impulses received and the physical activity of the animals.

A speed limit advisory system provided by in-vehicle HMI considering auditory perception characteristics for connected environment

In-vehicle HMI (Human Machine Interface) systems are well studied due to their great application prospect, but the recent development of connected technologies raises more possibilities that this technology provides more accurate speed limit warnings to ensure driver safety according to specific vehicle and road parameters. To capitalize on the potential of in-vehicle HMI systems to provide auditory and visual warnings to drivers and to improve adoption and utilization of this warning information. To this end, we designed a speed limit advisory system (SLAS) that recommended reduced speeds for hazardous sections of road, communicated to drivers by their in-vehicle HMI systems. Frontal distance models of single and gradient auditory warning were implanted into the systems to determine the warning timing. We then tested these SLASs in a high-fidelity simulator in order to evaluate their utility. 70 participants (mean age = 28.7 years; 36 male) drove through a simulated 15 km stretch of one-way two-lane rural road. We evaluated five different warning modes: single visual (SV), single audio visual (SAV), gradient visual (GV), gradient audio visual (GAV) or control (roadside sign). Participants using the SLAS slowed down significantly compared to the control group before entering the curve, with drivers receiving GAV warnings driving lowest speeds. Less experienced drivers exhibited higher compliance with GAMs (GV or GAV). The SLAS was generally considered useful though not by drivers with>10 years of driving experience. Drivers tended to prefer singular warnings to gradated warnings, which were rated as equally preferable to roadside signage. Eye tracking data indicated that none of the SLAS modes were overly distracting to the drivers. Overall, we find that the SLAS improves driver safety while producing no obvious distraction. The main difficulty lies in persuading experienced drivers to use the system. In a word, the results of this study provide validation for the concept of HMI warning system using connected technology in hazardous road areas and help determine the appropriate timing of in-vehicle warnings.

Current and Future Approaches to Mitigate Conflict between Humans and Asian Elephants: The Potential Use of Aversive Geofencing Devices.

Asian elephants are a principal cause of human-wildlife conflict. This results in the death/injury of elephants and humans and large-scale crop and property damage. Most current human-elephant conflict (HEC) mitigation tools lack the flexibility to accommodate the ecological needs of elephants and are ineffective at reducing HEC in the long-term. Here we review common HEC mitigation tools used in Asia and the potential of Aversive Geofencing Devices (AGDs) to manage problem elephants. AGDs can be configured to monitor animal movements in real-time and deliver auditory warnings followed by electric stimuli whenever animals attempt to move across user-specified virtual boundaries. Thus, AGDs are expected to condition elephants to avoid receiving shocks and keep them away from virtually fenced areas, while providing alternative routes that can be modified if required. Studies conducted using AGDs with other species provide an overview of their potential in conditioning wild animals. We recommend that the efficacy and welfare impact of AGDs be evaluated using captive elephants along with public perception of using AGDs on elephants as a means of addressing the inherent deficiencies of common HEC mitigation tools. If elephants could be successfully conditioned to avoid virtual fences, then AGDs could resolve many HEC incidents throughout Asia.

Danger or avoidance indication: Dynamics interact with semantics in auditory icons to avoid collisions

This study investigates how auditory icons with inherent meanings and dynamics in collision warnings affect warning message enhancement in driving. An experiment involving 36 participants was conducted. These participants were randomly presented with three types of warning sounds, including two auditory icons with different semantics (i.e., an avoidance-indicated auditory icon horn and a danger-indicated auditory icon collision) and an “earcon” (with an abstract pure tone). Each warning sound had dynamic and static forms. Results show that the danger-indicated auditory icons and earcons led to better driving performance than the avoidance-indicated auditory icons for brake reaction time, time to collision, and time to throttle release. Meanwhile, both the danger- and avoidance-indicated auditory icons were more efficient, emergent, likable, and intelligible than earcons. Dynamic sounds also resulted in stronger braking. When designing auditory icons, the impact of both their inherent meanings and dynamics on the subjective experience of drivers should be considered. Relevance to industryDesign principles of anti-collision auditory warning systems were proposed to indicate hazards in driving and assist drivers in an emergency, contributing to warning and ergonomics in the design industrial field.

Modeling the effects of perceived intuitiveness and urgency of various auditory warnings on driver takeover performance in automated vehicles

Existing driver models mainly account for drivers’ responses to visual cues in manually controlled vehicles. The present study is one of the few attempts to model drivers’ responses to auditory cues in automated vehicles. It developed a mathematical model to quantify the effects of characteristics of auditory cues on drivers’ response to takeover requests in automated vehicles. The current study enhanced queuing network-model human processor (QN-MHP) by modeling the effects of different auditory warnings, including speech, spearcon, and earcon. Different levels of intuitiveness and urgency of each sound were used to estimate the psychological parameters, such as perceived trust and urgency. The model predictions of takeover time were validated via an experimental study using driving simulation with resultant R squares of 0.925 and root-mean-square-error of 73 ms. The developed mathematical model can contribute to modeling the effects of auditory cues and providing design guidelines for standard takeover request warnings for automated vehicles.

Developing a two-stage auditory warning system for safe driving and eco-driving at signalized intersections: A driving simulation study

In-vehicle intersection warning systems represent a promising approach for informing drivers of potential danger to reduce crashes and improve intersection safety. However, there is limited research on drivers’ eco-driving performances, such as fuel consumption and emission, when drivers adapt their behaviors to the systems. In this study, an innovative two-stage in-vehicle intersection warning system was proposed to reduce red-light running (RLR) violations. Forty-five drivers participated in a simulated driving experiment and their driving performances at the intersections were evaluated to examine the effectiveness of the warning system. The measures included stop/go decision, RLR rate, average speed and deceleration, brake transition time, brake level, fuel consumption, and emission of CO and NOx. The results indicated that the warning system had a positive effect on drivers’ safe driving and eco-driving performances, such as reducing the RLR rate, advancing and smoothing the deceleration and reducing fuel consumption and emission. Moreover, the impact of warning on drivers’ performances varied with the time to the onset of yellow light. The research has practical implications for the automobile industry to use vehicle-to-infrastructure technology in the design of in-vehicle warning systems to improve driver behaviors at intersections.