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Left or Right: Auditory Collision Warnings for Driving Assistance Systems
Abstract
Assistance driving systems aim to facilitate human behavior and increase safety on the road. These systems comprise common systems such as forward collision warning systems, lane deviation warning systems, and even park assistance systems. Warning systems can communicate with the driver through various modalities, but auditory warnings have the advantage of not further tasking visual resources that are primarily used for driving. Auditory warnings can also be presented from a certain location within the cab environment to be used by the driver as a cue. Beattie, Baillie, Halvey, and McCall (2014) assessed presenting warnings in stereo configuration, coming from one source, and bilateral configuration, panned fully from left or right, and found that drivers felt more in control with lateral warnings than stereo warnings when the car was in self-driving mode. Straughn, Gray, and Tan (2009) examined laterally presented auditory warnings to signal potential collisions. They found that the ideal presentation of warnings in either the avoidance direction, in which the driver should direct the car to avoid a collision, or the collision direction, in which the potential collision is located, was dependent on time to collision. Wang, Proctor, and Pick (2003) applied the stimulus-response compatibility principle to auditory warning design by using a steering wheel in a non-driving scenario and found that a tone presented monaurally in the avoidance-direction led to the fastest steering response. However, the reverse finding occurred when similar experiments utilized a driving simulator in a driving scenario (Straughn et al., 2009; Wang, Pick, Proctor, & Ye, 2007).
... Arguably, ADAS also provides opportunities for upskilling drivers on safety, such as choosing increased safety margins or using turn signals. Previous research has illustrated that ADAS can change driver behaviour in a positive way, for example ADAS providing auditory collision warnings aimed to direct the attention of the participants towards the location of a pedestrian crossing the road and thus resulting in earlier responses (Sabic et al., 2017;Haque et al., 2021). The potential use of ADAS as an educational tool should be examined in future research. ...
Advanced Driver Assistance Systems (ADAS) have shown substantial potential to increase road safety. To guarantee a growing presence and correct use of ADAS, road safety initiatives such as driver education and programs to promote safer vehicles need to be oriented towards the specific needs of individual drivers. The aim of this study was to explore a sample of Australian drivers' rationale for driving a vehicle with ADAS and the strategies that they use when learning to operate the functions of ADAS. Semi-structured interviews were conducted with 48 Australian drivers aged between 19 and 78 years (M = 41.54, SD = 16.32; 25 females). The results were organised into four themes: (i) reasons for driving/purchasing a car with ADAS, (ii) systems influencing driver purchasing systems, (iii) strategies used by drivers when learning about ADAS, and (iv) perceptions regarding the importance of learning and training to use ADAS. Acquisition of vehicles with ADAS frequently occurred because of the perceived safety benefits of specific systems (e.g., rear parking sensor or in-vehicle information system). Additionally, some participants did not highlight the safety benefits as the main reason for driving/purchasing a car with ADAS. Indeed, some participants mentioned that ADAS acquisition was not a reasoned process but rather an opportunistic decision when upgrading their vehicles, mainly because these systems were already included in a vehicle. Regarding education, it was found that participants were using trial-and-error as their main approach to learning about the capabilities of ADAS and official sources of knowledge about the system were rarely consulted. On a positive note, participants recognised the importance of learning to use ADAS systems correctly, showing that there is demand for effective and engaging driver education.
... Effective directional cues help drivers avoid collisions faster (Bella and Silvestri, 2017). Previous studies have attempted to design spatially presented auditory collision warnings to facilitate the responses of drivers to potential collisions (Sabic and Chen, 2017). However, researchers have not yet reached a consensus on whether these warnings should be presented in the collision or avoidance direction. ...
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 industry
Design 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.
... In choice-reaction tasks, responses are faster when the locations of stimulus and response correspond than when they do not (Fitts & Seeger, 1953). The influence of this spatial stimulus-response compatibility (SRC) is prevalent in operational settings, such as driving a car (Müsseler, Aschersleben, Arning, & Proctor, 2009;Sabic & Chen, 2017) and piloting an aircraft (Yamaguchi & Proctor, 2006). Although automated systems are quickly developing, human operations are still critical in maintaining safety in complex environments. ...
The valence of stimuli can influence performance in the spatial stimulus–response compatibility task, but this observation could arise from the process of selecting responses or selecting stimulus–response mappings. The response-selection account proposes that spatial compatible and incompatible keypress responses serve as approaching and avoiding actions to a valenced target. The mapping-selection account suggests that there is congruence between stimulus valence and stimulus–response mappings; positive-compatible/negative-incompatible is more congruent than negative-compatible/positive-incompatible. Whereas affective valence was part of the target stimuli to which participants responded in previous studies, the present study isolated affective valence from the target by presenting an additional mapping cue separately from the target, so that spatially compatible and incompatible keypress responses could no longer serve as approaching and avoiding actions to valenced target stimuli. The present results revealed that responses were still faster when positive and negative mapping cues were assigned to the spatially compatible and incompatible mappings than when the assignment was reversed. The finding supports the mapping-selection account, indicating that positive and negative cues influence performance without approach–avoidance actions to valenced stimuli. The experiment provides important implications as to how tasks are represented and are dependent on affective processing.
The availability of advisory warnings via Vehicle-to-Vehicle and Vehicle-to-Infrastructure communication in the connected environments is expected to gradually increase over the next few years. Much of the research on advisory warning systems have examined driving behaviour in response to unexpected driving hazards; however, very little research has been conducted on common driving interactions such as interacting with pedestrians at pedestrian crossings. Therefore, the aim of this study is to investigate the effects of the connected environment on driving behaviour at pedestrian crossings. The connected environment was designed within the CARRS-Q advanced driving simulator. A combination of auditory (beep sound) and imagery message was simultaneously displayed on the windscreen to advise the driver on the presence of a pedestrian entering from a sidewalk. Seventy-eight licensed drivers drove the simulator in two driving conditions, namely, baseline and connected environment. The participants were 18-65 years old, and a third of them were females. Drivers' response to the driving aids and the braking behaviour were analysed in the latent response phase and the observable response phase, and the corresponding response times were modelled using the hazard-based duration modelling approach. In particular, this study applied the Weibull accelerated failure time model with shared frailty accounting for multiple observations from the same driver. Results showed that the time taken to respond to the pedestrian in the latent response phase was longer when the advisory warning was provided to the drivers, but the corresponding time in the observable response phase was shorter, indicating that drivers take an informed decision in the connected environment. Moreover, the safety margin-measured in terms of time-to-collision-was higher in the connected environment than the traditional driving environment, indicating a safer behavioural adaptation towards the connected environment.
Objective
The effectiveness of three types of in-vehicle warnings was assessed in a driving simulator across different noise conditions.
Background
Although there has been much research comparing different types of warnings in auditory displays and interfaces, many of these investigations have been conducted in quiet laboratory environments with little to no consideration of background noise. Furthermore, the suitability of some auditory warning types, such as spearcons, as car warnings has not been investigated.
Method
Two experiments were conducted to assess the effectiveness of three auditory warnings (spearcons, text-to-speech, auditory icons) with different types of background noise while participants performed a simulated driving task.
Results
Our results showed that both the nature of the background noise and the type of auditory warning influenced warning recognition accuracy and reaction time. Spearcons outperformed text-to-speech warnings in relatively quiet environments, such as in the baseline noise condition where no music or talk-radio was played. However, spearcons were not better than text-to-speech warnings with other background noises. Similarly, the effectiveness of auditory icons as warnings fluctuated across background noise, but, overall, auditory icons were the least efficient of the three warning types.
Conclusion
Our results supported that background noise can have an idiosyncratic effect on a warning’s effectiveness and illuminated the need for future research into ameliorating the effects of background noise.
Application
This research can be applied to better present warnings based on the anticipated auditory environment in which they will be communicated.
Objective:
The primary aim of the current study was to determine whether monitoring the roadway for hazards during automated driving results in a vigilance decrement.
Background:
Although automated vehicles are relatively novel, the nature of human-automation interaction within them has the classic hallmarks of a vigilance task. Drivers must maintain attention for prolonged periods of time to detect and respond to rare and unpredictable events, for example, roadway hazards that automation may be ill equipped to detect. Given the similarity with traditional vigilance tasks, we predicted that drivers of a simulated automated vehicle would demonstrate a vigilance decrement in hazard detection performance.
Method:
Participants "drove" a simulated automated vehicle for 40 minutes. During that time, their task was to monitor the roadway for roadway hazards.
Results:
As predicted, hazard detection rate declined precipitously, and reaction times slowed as the drive progressed. Further, subjective ratings of workload and task-related stress indicated that sustained monitoring is demanding and distressing and it is a challenge to maintain task engagement.
Conclusion:
Monitoring the roadway for potential hazards during automated driving results in workload, stress, and performance decrements similar to those observed in traditional vigilance tasks.
Application:
To the degree that vigilance is required of automated vehicle drivers, performance errors and associated safety risks are likely to occur as a function of time on task. Vigilance should be a focal safety concern in the development of vehicle automation.
Warnings are integral to ensuring the safe operation of a vehicle. The use of auditory alerts and warnings has the potential to alleviate drivers' workload, increase drivers' situation awareness, and facilitate efficient and safe driving. The present study assessed the ability of individuals to react to auditory warnings. The warnings took the form of text-to-speech (TTS), spearcons at two levels of linear compression, and auditory icons. To assess usability, the NASA Task Load Index and an annoyance question were used. Participants pressed a space bar when they recognized a warning, and then identified auditory warnings by selecting a picture corresponding to the meaning of the warning. The results showed that participants responded to the fastest spearcon warnings more quickly compared to TTS and auditory icons. Responses to auditory icons were slowest compared to all other auditory types. Importantly, responses to spearcon warnings were no less accurate in comparison to TTS warnings.
Objective:
The aim of this study was to review existing research into driver control transitions and to determine the time it takes drivers to resume control from a highly automated vehicle in noncritical scenarios.
Background:
Contemporary research has moved from an inclusive design approach to adhering only to mean/median values when designing control transitions in automated driving. Research into control transitions in highly automated driving has focused on urgent scenarios where drivers are given a relatively short time span to respond to a request to resume manual control. We found a paucity in research into more frequent scenarios for control transitions, such as planned exits from highway systems.
Method:
Twenty-six drivers drove two scenarios with an automated driving feature activated. Drivers were asked to read a newspaper, or to monitor the system, and to relinquish, or resume, control from the automation when prompted by vehicle systems.
Results:
Significantly longer control transition times were found between driving with and without secondary tasks. Control transition times were substantially longer than those reported in the peer-reviewed literature.
Conclusion:
We found that drivers take longer to resume control when under no time pressure compared with that reported in the literature. Moreover, we found that drivers occupied by a secondary task exhibit larger variance and slower responses to requests to resume control. Workload scores implied optimal workload.
Application:
Intra- and interindividual differences need to be accommodated by vehicle manufacturers and policy makers alike to ensure inclusive design of contemporary systems and safety during control transitions.
In partially automated cars, it is vital to understand the driver state, especially the driver's cognitive load. This might indicate whether the driver is alert or distracted, and if the car can safely transfer control of driving. In order to better understand the relationship between cognitive load and the driver performance in a partially autonomous vehicle, functional near infrared spectroscopy (fNIRS) measures were employed to study the activation of the prefrontal cortex of drivers in a simulated environment. We studied a total of 14 participants while they drove a partially autonomous car and performed common secondary tasks. We observed that when participants were asked to monitor the driving of an autonomous car they had low cognitive load compared to when the same participants were asked to perform a secondary reading or video watching task on a brought in device. This observation was in line with the increased drowsy behavior observed during intervals of autonomous system monitoring in previous studies. Results demonstrate that fNIRS signals from prefrontal cortex indicate additional cognitive load during manual driving compared to autonomous. Such brain function metrics could be used with minimally intrusive and low cost sensors to enable real-time assessment of driver state in future autonomous vehicles to improve safety and efficacy of transfer of control.
This study investigated whether multimodal redundant warnings presented by advanced
assistance systems reduce brake response times. Warnings presented by assistance systems
are designed to assist drivers by informing them that evasive driving maneuvers are needed in
order to avoid a potential accident. If these warnings are poorly designed, they may distract
drivers, slow their responses, and reduce road safety. In two experiments, participants drove a
simulated vehicle equipped with a rear-end collision avoidance system. Auditory,
vibrotactile, and multimodal warnings were presented when the time-to-collision was shorter
than five seconds. The effects of these warnings were investigated with participants
performing a concurrent cell phone conversation (Exp. 1) or driving in high-density traffic
(Exp. 2). Braking times and subjective workload were measured. Multimodal redundant
warnings elicited faster braking reaction times. These warnings were found to be effective
even when talking on a cell phone (Exp. 1) or driving in dense traffic (Exp. 2). Multimodal
warnings produced higher ratings of urgency, but ratings of frustration did not increase
compared to other warnings. Findings obtained in these two experiments are important given
that faster braking responses may reduce the potential for a collision.
There is currently a distinct lack of design consideration associated with autonomous vehicles and their impact on human factors. Research has yet to consider fully the impact felt by the driver when he/she is no longer in control of the vehicle [12]. We propose that spatialised auditory feedback could be used to enhance driver awareness to the intended actions of autonomous vehicles. We hypothesise that this feedback will provide drivers with an enhanced sense of control. This paper presents a driving simulator study where 5 separate auditory feedback methods are compared during both autonomous and manual driving scenarios. We found that our spatialised auditory presentation method alerted drivers to the intended actions of autonomous vehicles much more than all other methods and they felt significantly more in control during scenarios containing sound vs. no sound. Finally, that overall workload in autonomous vehicle scenarios was lower compared to manual vehicle scenarios.
This study explores, in the context of semi-autonomous driving, how the content of the verbalized message accompanying the car’s autonomous action affects the driver’s attitude and safety performance. Using a driving simulator with an auto-braking function, we tested different messages that provided advance explanation of the car’s imminent autonomous action. Messages providing only “how” information describing actions (e.g., “The car is braking”) led to poor driving performance, whereas “why” information describing reasoning for actions (e.g., “Obstacle ahead”) was preferred by drivers and led to better driving performance. Providing both “how and why” resulted in the safest driving performance but increased negative feelings in drivers. These results suggest that, to increase overall safety, car makers need to attend not only to the design of autonomous actions but also to the right way to explain these actions to the drivers.
Automation essentially enables drivers to become ‘‘hands and feet free’’ but not necessarily ‘‘mind-free’’
during vehicle operation and on these grounds, increased vehicle automation may contribute to safety
concerns rather than overcome them. Although automated systems were originally designed to improve
driver safety by reducing driver fatigue, stress and ultimately error, there is growing concern within the
Ergonomics and Human Factors community that automation may introduce additional complexity into
the driving task placing increased pressure on drivers to monitor both the environment and behaviour
of vehicle sub-systems. This paper considers how increasing the level of automation within the sub-tasks
of driving may affect the traditional role of the driver. Using the Distributed Cognition approach and
Operator Sequence Diagrams as a representational aid, this paper indicates that the level at which automation is set significantly affects the dynamism of the system network.
This study examined the effect of the stimulus-response (S-R) compatibility of pedestrian collision warnings presented via different sensory modalities in a driving simulator. Despite the well-established fact that reaction times (RT) are faster under S-R compatible conditions, the majority of collision warning research has used S-R incompatible warnings (i.e., the warning comes from the direction of the obstacle to be avoided not the desired response direction). Thirty-two participants in a fixed-base driving simulator drove on a three-lane urban road in which pedestrians randomly walked from the sidewalk into the roadway. Collision warnings in two different modalities (tactile and auditory) were compared with a no warning condition. Participants were equally divided into one of four conditions representing all combinations of two levels of warning S-R compatibility (compatible and incompatible) and two levels of warning timing (early and late). For early warnings, incompatible warnings were most effective as shown by a significantly shorter steering RT and larger clearance distance. For late warnings, compatible warnings were most effective. For early warnings, RTs were significantly faster in the tactile condition. The relationship between collision warning effectiveness and S-R compatibility in driving is dependent on whether the driver has time to evaluate the situation before collision will occur. Our findings have important implications for the design of effective tactile and auditory collision warning systems. However, further research is needed to determine if these effects occur in more representative driving conditions (e.g., lower pedestrian incursion rate and unreliable warnings).
This paper examines the potential effectiveness of the following three precollision system (PCS) algorithms: 1) forward collision warning only; 2) forward collision warning and precrash brake assist; and 3) forward collision warning, precrash brake assist, and autonomous precrash brake. Real-world rear-end crashes were extracted from a nationally representative sample of collisions in the United States. A sample of 1396 collisions, corresponding to 1.1 million crashes, were computationally simulated as if they occurred, with the driver operating a precollision-system-equipped vehicle. A probability-based framework was developed to account for the variable driver reaction to the warning system. As more components were added to the algorithms, greater benefits were realized. The results indicate that the exemplar PCS investigated in this paper could reduce the severity (i.e., ΔV) of the collision between 14% and 34%. The number of moderately to fatally injured drivers who wore their seat belts could have been reduced by 29% to 50%. These collision-mitigating algorithms could have prevented 3.2% to 7.7% of rear-end collisions. This paper shows the dramatic reductions in serious and fatal injuries that a PCS, which is one of the first intelligent vehicle technologies to be deployed in production cars, can bring to highway safety when available throughout the fleet. This paper also presents the framework of an innovative safety benefits methodology that, when adapted to other emerging active safety technologies, can be employed to estimate potential reductions in the frequency and severity of highway crashes.
The aim of this study was to integrate empirical data showing the effects of interrupting task modality on the performance of an ongoing visual-manual task and the interrupting task itself. The goal is to support interruption management and the design of multimodal interfaces.
Multimodal interfaces have been proposed as a promising means to support interruption management.To ensure the effectiveness of this approach, their design needs to be based on an analysis of empirical data concerning the effectiveness of individual and redundant channels of information presentation.
Three meta-analyses were conducted to contrast performance on an ongoing visual task and interrupting tasks as a function of interrupting task modality (auditory vs. tactile, auditory vs. visual, and single modality vs. redundant auditory-visual). In total, 68 studies were included and six moderator variables were considered.
The main findings from the meta-analyses are that response times are faster for tactile interrupting tasks in case of low-urgency messages.Accuracy is higher with tactile interrupting tasks for low-complexity signals but higher with auditory interrupting tasks for high-complexity signals. Redundant auditory-visual combinations are preferable for communication tasks during high workload and with a small visual angle of separation.
The three meta-analyses contribute to the knowledge base in multimodal information processing and design. They highlight the importance of moderator variables in predicting the effects of interruption task modality on ongoing and interrupting task performance.
The findings from this research will help inform the design of multimodal interfaces in data-rich, event-driven domains.
This paper extends previous research on two approaches to human-centred automation: (1) intermediate levels of automation (LOAs) for maintaining operator involvement in complex systems control and facilitating situation awareness; and (2) adaptive automation (AA) for managing operator workload through dynamic control allocations between the human and machine over time. Some empirical research has been conducted to examine LOA and AA independently, with the objective of detailing a theory of human-centred automation. Unfortunately, no previous work has studied the interaction of these two approaches, nor has any research attempted to systematically determine which LOAs should be used in adaptive systems and how certain types of dynamic function allocations should be scheduled over time. The present research briefly reviews the theory of human-centred automation and LOA and AA approaches. Building on this background, an initial study was presented that attempts to address the conjuncture of these two approaches to human-centred automation. An experiment was conducted in which a dual-task scenario was used to assess the performance, SA and workload effects of low, intermediate and high LOAs, which were dynamically allocated (as part of an AA strategy) during manual system control for various cycle times comprising 20, 40 and 60% of task time. The LOA and automation allocation cycle time (AACT) combinations were compared to completely manual control and fully automated control of a dynamic control task performed in conjunction with an embedded secondary monitoring task. Results revealed LOA to be the driving factor in determining primary task performance and SA. Low-level automation produced superior performance and intermediate LOAs facilitated higher SA, but this was not associated with improved performance or reduced workload. The AACT was the driving factor in perceptions of primary task workload and secondary task performance. When a greater percentage of primary task time was automated, operator perceptual resources were freed-up and monitoring performance on the secondary task improved. Longer automation cycle times than have previously been studied may have benefits for overall human–machine system performance. The combined effect of LOA and AA on all measures did not appear to be ‘additive’ in nature. That is, the LOA producing the best performance (low level automation) did not do so at the AACT, which produced superior performance (maximum cycle time). In general, the results are supportive of intermediate LOAs and AA as approaches to human-centred automation, but each appears to provide different benefits to human–machine system performance. This work provides additional information for a developing theory of human-centred automation.
The study was designed to show how driver attention to the road scene and engagement of a choice of secondary tasks are affected by the level of automation provided to assist or take over the basic task of vehicle control. It was also designed to investigate the difference between support in longitudinal control and support in lateral control.
There is comparatively little literature on the implications of automation for drivers' engagement in the driving task and for their willingness to engage in non-driving-related activities.
A study was carried out on a high-level driving simulator in which drivers experienced three levels of automation: manual driving, semiautomated driving with either longitudinal or lateral control provided, and highly automated driving with both longitudinal and lateral control provided. Drivers were free to pay attention to the roadway and traffic or to engage in a range of entertainment and grooming tasks.
Engagement in the nondriving tasks increased from manual to semiautomated driving and increased further with highly automated driving. There were substantial differences in attention to the road and traffic between the two types of semiautomated driving.
The literature on automation and the various task analyses of driving do not currently help to explain the effects that were found. Lateral support and longitudinal support may be the same in terms of levels of automation but appear to be regarded rather differently by drivers.
The objective was to study the involuntary capture of attention by spoken words varying in intonation and valence. In studies of verbal alarms, the propensity of alarms to capture attention has been primarily assessed with the use of subjective ratings of their perceived urgency. Past studies suggest that such ratings vary with the alarms' spoken urgency and content.
We measured attention capture by spoken words varying in valence (negative vs. neutral) and intonation (urgently vs. nonurgently spoken) through subjective ratings and behavioral measures. The key behavioral measure was the response latency to visual stimuli in the presence of spoken words breaking away from the periodical repetition of a tone.
The results showed that all words captured attention relative to a baseline standard tone but that this effect was partly counteracted by a relative speeding of responses for urgently compared with nonurgently spoken words. Word valence did not affect behavioral performance. Rating data showed that both intonation and valence increased significantly perceived urgency and attention grabbing without any interaction. The data suggest a congruency between subjective ratings and behavioral performance with respect to spoken intonation but not valence. This study demonstrates the usefulness and feasibility of objective measures of attention capture to help design efficient alarm systems.
Effects of a side collision-avoidance system (SCAS) signal on driving behavior were examined in an environment in which a nagivation signal was also used. Sixteen undergraduate students participated in this study, and a computer-based STISIM driving simulator was used in the project. Subjects were asked to respond to two signals, a visually displayed directional signal generated by a simulated navigation system (NAS) and a monaural auditory tone from a simulated SCAS presented after a NAS signal. Subjects were instructed that the SCAS signal conveyed directional information about an impending threat (the location of the danger from which they were to turn, or the escape direction toward which they were to turn). Contrary to previous findings in a non-driving environment (Wang et al., 2003), response time (RT) was significantly shorter for the group in which the location of the SCAS signal was spatially compatible with the location of the danger than for the group in which the SCAS signal location was incompatible with the location of the danger. Mean RT was not significantly shorter when the direction of the NAS signal and the location of the SCAS signal corresponded than when they did not. Given that subjects tended to withhold responding until they perceived the encroaching car, the benefit of a SCAS may be to direct a driver's attention in the direction of an impending threat before the driver would ordinarily detect it.
Both the behavioural and subjective impacts of single-word spoken warnings were examined. Behaviourally, the effect of infrequently occurring warnings was studied through their disruptive impact on a visually presented serial recall task. In separate experiments, ratings of the same words were elicited. Experiment 1 showed a localized effect of the warnings (on the item immediately following the warning), with the urgently intoned warning having a greater disruptive effect than its valence (emotional content). Valence and intonation (urgency) did not interact. The performance changes were mirrored in the ratings of the words. Experiment 2 showed no systematic effect on performance of either the action-relatedness of the word or its lexicality. There was, however, a systematic effect of lexicality but not action-relatedness on ratings. The study demonstrates the feasibility of using objective performance methods to establish the likely effects of verbal warnings and the utility of using such methods for the design of alarm systems. Copyright © 2012 John Wiley & Sons, Ltd.
Active safety systems hold great potential for reducing accident frequency and severity by warning the driver and/or exerting automatic vehicle control ahead of crashes. This paper presents a novel active pedestrian safety system that combines sensing, situation analysis, decision making, and vehicle control. The sensing component is based on stereo vision, and it fuses the following two complementary approaches for added robustness: 1) motion-based object detection and 2) pedestrian recognition. The highlight of the system is its ability to decide, within a split second, whether it will perform automatic braking or evasive steering and reliably execute this maneuver at relatively high vehicle speed (up to 50 km/h). We performed extensive precrash experiments with the system on the test track (22 scenarios with real pedestrians and a dummy). We obtained a significant benefit in detection performance and improved lateral velocity estimation by the fusion of motion-based object detection and pedestrian recognition. On a fully reproducible scenario subset, involving the dummy that laterally enters into the vehicle path from behind an occlusion, the system executed, in more than 40 trials, the intended vehicle action, i.e., automatic braking (if a full stop is still possible) or automatic evasive steering.
This study examined the effectiveness of rear-end collision warnings presented in different sensory modalities while drivers were engaged in cell phone conversations in a driving simulator.
Tactile and auditory collision warnings have been shown to improve braking response time (RT) in rear-end collision situations. However, it is not clear how effective these warnings are when the driver is engaged in attentionally demanding secondary tasks, such as talking on a cell phone.
Sixteen participants in a driving simulator experienced three collision warning conditions (none, tactile, and auditory) in three conversation conditions (none, simple hands free, complex hands free). Driver RT was captured from warning onset to brake initiation (WON2B).
WON2B times for auditory warnings were significantly larger for simple conversations compared with no conversation (+148 ms), whereas there was no significant difference between these conditions for tactile warnings (+53 ms). For complex conversations, WON2B times for both tactile (+146 ms) and auditory warnings (+221 ms) were significantly larger than during no conversation. During complex conversations, tactile warnings produced significantly shorter WON2B times than no warning (-141 ms).
Tactile warnings are more effective than auditory warnings during both simple and complex conversations.
These results indicate that tactile rear-end collision warnings have the potential to offset some of the driving impairments caused by cell phone conversations.
The hypothesis that abrupt visual onsets capture attention automatically, as suggested by Yantis and Jonides (1984) was tested in four experiments. A centrally located cue directed attention to one of several stimulus positions in preparation for the identification of a target letter embedded in an array of distractor letters. In all experiments, one stimulus (either the target or one of the distractors) had an abrupt onset; the remaining letters did not. The effectiveness of the cue was manipulated (varying either its duration or its predictive validity) to test whether abrupt onsets capture attention even when subjects are in a highly focused attentional state. Results showed that onsets do not necessarily capture attention in violation of an observer's intentions. A mechanism for partially automatic attentional capture by abrupt onset is proposed, and the diagnosticity of the intentionality criterion for automaticity is discussed.
Bartlett viewed thinking as a high level skill exhibiting ballistic properties that he called its “point of no return”. This paper explores one aspect of cognition through the use of a simple model task in which human subjects are asked to commit attention to a position in visual space other than fixation. This instruction is executed by orienting a covert (attentional) mechanism that seems sufficiently time locked to external events that its trajectory can be traced across the visual field in terms of momentary changes in the efficiency of detecting stimuli. A comparison of results obtained with alert monkeys, brain injured and normal human subjects shows the relationship of this covert system to saccadic eye movements and to various brain systems controlling perception and motion. In accordance with Bartlett's insight, the possibility is explored that similar principles apply to orienting of attention toward sensory input and orienting to the semantic structures used in thinking.
Five experiments were conducted using 4- and 6-choice stimulus-response compatibility tasks with graphic and alphabetic stimuli, and keypress and verbal responses. A comparison of performance with compatible, incompatible, and neutral conditions shows that when a stimulus set is perceptually, conceptually, or structurally similar to a response set, (a) mean reaction times (RTs) are faster when individual stimuli and responses match than when they do not match, (b) this is true whether the stimulus and response sets are similar on relevant or irrelevant dimensions, (c) this "compatibility effect" is greater when the dimensions are relevant than when they are irrelevant, and (d) whether the dimensions are relevant or irrelevant, the faster RTs are due to a facilitative process and the slower RTs to an interfering process. These results are accounted for by the dimensional overlap model.
Operators in high-risk domains such as aviation often need to make decisions under time pressure and uncertainty. One way to support them in this task is through the introduction of decision support systems (DSSs). The present study examined the effectiveness of two different DSS implementations: status and command displays. Twenty-seven pilots (9 pilots each in a baseline, status, and command group) flew 20 simulated approaches involving icing encounters. Accuracy of the decision aid (a smart icing system), familiarity with the icing condition, timing of icing onset, and autopilot usage were varied within subjects. Accurate information from either decision aid led to improved handling of the icing encounter. However, when inaccurate information was presented, performance dropped below that of the baseline condition. The cost of inaccurate information was particularly high for command displays and in the case of unfamiliar icing conditions. Our findings suggest that unless perfect reliability of a decision aid can be assumed, status displays may be preferable to command displays in high-risk domains (e.g., space flight, medicine, and process control), as the former yield more robust performance benefits and appear less vulnerable to automation biases.
Stroop effects might be due to differences in stimulus-response compatibility (SRC) and/or to differences in stimulus-stimulus compatibility (SSC). Recent evidence for the role of SSC is inconclusive, because there were no controls for effects of SRC that are based on short-term associations between stimuli and responses (i.e., associations set up as the result of task instructions). In two experiments, SRC effects were controlled for. Regardless of whether the irrelevant and the relevant stimulus features were separated (Experiment 1) or integrated in one stimulus (Experiment 2), the results revealed an effect of SSC and an effect of SRC that was based on short-term associations. The results thus confirm that both processes at the level of encoding and processes at the level of response selection contribute to the Stroop effect.
The authors examined clockwise and counterclockwise wheel-rotation responses to high- or low-pitched tones presented in participants' (N = 96, Experiment 1; N = 48, Experiment 2; N = 48, Experiment 3) left and right ears. In Experiment 1, a Simon effect (fastest responding when tone location and direction of wheel turn corresponded) was obtained when participants' hands were at the top or middle of the wheel but not at the bottom. With the bottom hand placement, a Simon effect was induced by instructions emphasizing hand movements but not by instructions emphasizing wheel movements (Experiment 2), and by a visual cursor controlled by the wheel but not one triggered by the response (Experiment 3). The results of the experiments showed that the nature of the task and the instructed action goal influence the direction of the Simon effect.
One of the most significant safety concerns regarding Highly-Automated Driving (HAD) is
drivers’ ability to regain control of the vehicle safely. Vibro-tactile alerts were already suggested
as an effective modality for Take-Over Requests (TOR) in terms of reducing reaction
times. However, it is not clear yet whether such alerts should be compatible or incompatible
with the location of hazards that might be present when the TOR is initiated. Studies
regarding tactile directionality in other domains, and in manual vehicles have found mixed
results. It is argued that part of the contradictory evidence may be related to contextual differences
between the driving domain and other domains. Thus, this study aimed to test
which directional design would be preferable for TORs in time-critical situations.
Twenty-seven participants drove a highly-automated vehicle on a highway with two lanes
in each travel direction, in a driving simulator. Each participant experienced five TORs in
which they were required to take control and divert their vehicle away from an impending
hazard that shut down an entire lane and was situated four seconds ahead. The disengagement
of the autonomous driver was signaled using a tactile alert. For the first group, the
tactile alert was directed towards the hazard (incompatible with the required action), for
the second, it was directed away from it (compatible with the required action), and for
the control group, the alert was non-directional. Results showed that drivers using the
compatible alert reacted faster and more accurately than those using the incompatible
alert. Participants using the non-directional alert reacted slower and less accurately than
participants in both directional groups. The results contradict previous findings in the manual
driving domain, where drivers are faster and more accurate to respond when the alert
is compatible with the location of the hazard and not with the direction of the required
action. It is argued that these discrepancies stem from the modified HAD driving task
demands where drivers are disengaged from the driving task for long periods and are less
aware of the driving environment. The implications for the design of autonomous vehicles
are discussed.
Objective::
To determine whether response-effect (R-E) compatibility or stimulus-response (S-R) compatibility is more critical for touchless gesture responses.
Background::
Content on displays can be moved in the same direction (S-R incompatible but R-E compatible) or opposite direction (S-R compatible but R-E incompatible) as the touchless gesture that produces the movement. Previous studies suggested that it is easier to produce a button-press response when it is R-E compatible (and S-R incompatible). However, whether this R-E compatibility effect also occurs for touchless gesture responses is unknown.
Method::
Experiments 1 and 2 employed an R-E compatibility manipulation in which participants made responses with an upward or downward touchless gesture that resulted in the display content moving in the same (compatible) or opposite (incompatible) direction. Experiment 3 employed an S-R compatibility manipulation in which the stimulus occurred at the upper or lower location on the screen.
Results::
Overall, only negligible influences of R-E compatibility on performing the touchless gestures were observed (in contrast to button-press responses), whereas S-R compatibility heavily affected the gestural responses.
Conclusion::
The R-E compatibility obtained in many previous studies with various types of responses appears not to hold for touchless gestures as responses.
Application::
The results suggest that in the design of touchless interfaces, unique factors may contribute to determining which mappings of gesture and display movements are preferred by users.
Mind-wandering involves a lapse in attention due to preoccupation with one’s own thoughts, the experience of which may interfere with performance on a primary task. The goal of this study was to investigate how task length and fatigue influenced the tendency to mind-wander while driving. We were also interested in whether the propensity to mind-wander could be predicted by individual differences in sustained attention, as measured by the Sustained Attention to Response Task (SART). Participants completed three 20–25 min drives, during which time pre-recorded thought-probes prompted participants to answer whether they were thinking of driving. Mind-wandering was measured both during the drive (in terms of the percentage of thought-probe trials where drivers reported that they were not thinking of driving), as well post-task (in terms of self-rated difficulty in focusing attention). Driving speed, steering variability and hazard response time were measured by the driving simulator, and drivers also rated their performance post-task. There were significant increases in self-rated difficulty focusing with time on task, and non-significant increases in reported mind-wandering. Driving speeds and steering variability also increased with time on task, but individual differences in sustained attention as measured by the SART did not predict these changes. Overall, the best advance predictor of mind-wandering was the number of hours of sleep the previous night. Mind-wandering and difficulty focusing were correlated with negative emotional rumination (e.g., worries, guilt, anger), though it is unclear whether negative emotionality causes mind-wandering or vice versa. This research has implications for both basic and applied research on individual differences and cognitive distraction, as well as practical safety implications in areas of driver training and autonomous vehicle development.
When a highly automated car reaches its operational limits, it needs to provide a takeover request (TOR) in order for the driver to resume control. The aim of this simulator-based study was to investigate the effects of TOR modality and left/right directionality on drivers' steering behaviour when facing a head-on collision without having received specific instructions regarding the directional nature of the TORs. Twenty-four participants drove three sessions in a highly automated car, each session with a different TOR modality (auditory, vibrotactile, and auditory-vibrotactile). Six TORs were provided per session, warning the participants about a stationary vehicle that had to be avoided by changing lane left or right. Two TORs were issued from the left, two from the right, and two from both the left and the right (i.e., nondirectional). The auditory stimuli were presented via speakers in the simulator (left, right, or both), and the vibrotactile stimuli via a tactile seat (with tactors activated at the left side, right side, or both). The results showed that the multimodal TORs yielded statistically significantly faster steer-touch times than the unimodal vibrotactile TOR, while no statistically significant differences were observed for brake times and lane change times. The unimodal auditory TOR yielded relatively low self-reported usefulness and satisfaction ratings. Almost all drivers overtook the stationary vehicle on the left regardless of the directionality of the TOR, and a post-experiment questionnaire revealed that most participants had not realized that some of the TORs were directional. We conclude that between the three TOR modalities tested, the multimodal approach is preferred. Moreover, our results show that directional auditory and vibrotactile stimuli do not evoke a directional response in uninstructed drivers. More salient and semantically congruent cues, as well as explicit instructions, may be needed to guide a driver into a specific direction during a takeover scenario.
Appropriate automation trust is a prerequisite for safe, comfortable and
efficient use of highly automated driving systems (HADS). Earlier research
indicates that a drivers’ nationality and Take-Over Requests (TOR) due to
imperfect system reliability might affect trust, but this has never been investigated
in the context of highly automated driving. A driving simulator study (N = 80)
showed that TORs only temporarily lowered trust in HADSs, and revealed
similarities in trust formation between German and Chinese drivers. Trust was
significantly higher after experiencing the system than before, both for German and
Chinese participants. However, Chinese drivers reported significantly higher
automation mistrust than German drivers. Self-report measures of automation trust
were not connected to behavioral measures. The results support a distinction
between automation trust and mistrust as separate constructs, short- and long-term
effects of TORs on automation trust, and cultural differences in automation trust.
AUTONOMOUS CARS PROMISE to give us back the time we spend in traffic, improve the flow of traffic, reduce accidents, deaths, and injuries, and make personal car travel possible for everyone regardless of their abilities or condition. But despite impressive demonstrations and technical advances, many obstacles remain on the road to fully autonomous cars.20 Overcoming the challenges to enabling autonomous cars to safely operate in highly complex driving situations may take some time. Manufacturers already produce partially automated cars, and a spirited competition to deliver the most sophisticated ones is under way. Cars that provide high levels of automation in some circumstances (such as highway driving) have already arrived in the marketplace and promise to be in the hands of a large number of car owners in the next few years.
This chapter describes the stimulus-response (S-R) compatibility and human factors. Human factors have been defined as the discipline that tries to optimize the relationship between technology and the human. The most common way to measure S-R compatibility, widely used in human factors, is to take a vote and several arrangements are portrayed and users are asked to select the S-R mapping they find most congenial. S-R compatibility is a construct. Its existence cannot be observed but can only be inferred from changes in behavior. It is found that when the S-R compatibility construct is used in basic research, one hopes that the construct is independent of any particular measuring instrument or measurement technique. Observations over a wide range of operational settings have identified a number of sources of incompatibility in generating appropriate responses to particular stimulus configurations. Figure-ground ambiguity is a major factor in the long-standing debate of whether orientation displays in aviation and space should be aircraft-referenced or horizon-referenced. A source of incompatibility between the indication on a display and the response of an operator is the role of intervening variables.
Stimulus-response compatibility has been a staple of human factors since the early 1950s, when it was established by Paul Fitts, one of the founders of human factors. The importance of maintaining spatial compatibility is indicated in textbooks, but maintaining compatibility in design is not a simple task because there are many factors that need to be taken into consideration. This article focuses on spatial compatibility and the more recently investigated affective compatibility, highlighting their implications for HCI. We also provide an overview of other cognitive compatibility principles and examples of their use in HCI. Advanced technology has increased the need for systematic consideration of compatibility phenomena in user interface design, and we end the article with a summary of key points for designers. Work in this area of cumulating the science of HCI can have many starting points and go off in many directions, but the eventual goal is clear: an applied science of human performance useful for HCI design, based on an integrated, coherent model of human information processing.B. E. John & A. Newell, 1989
This article reviews various different approaches to the design of unimodal and multisensory warning signals, in particular warning signals for use in alerting drivers to potentially dangerous situations. The design of optimal warning signals that are maximally effective in terms of the limitations that constrain human information processing are discussed in light of the latest findings emerging from cognitive neuroscience research. A new approach to the design of multisensory warning signals, involving the presentation of warning signals in different regions of space around a driver, is then critically examined.
The effects of a forward collision warning (FCW) and braking system (FCW+) were examined in a driving simulator study analyzing driving and gaze behavior and the engagement in a secondary task.
In-depth accident analyses indicate that a lack of appropriate expectations for possible critical situations and visual distraction may be the major causes of rear-end crashes. Studies with FCW systems have shown that a warning alone was not enough for a driver to be able to avoid the accident. Thus,an additional braking intervention by such systems could be necessary.
In a driving simulator experiment, 30 drivers took part in a car-following scenario in an urban area. It was assumed that different lead car behaviors and environmental aspects would lead to different drivers' expectations of the future traffic situation. Driving with and without FCW+ was introduced as a between-subjects factor.
Driving with FCW+ resulted in significantly fewer accidents in critical situations. This result was achieved by the system's earlier reaction time as compared with that of drivers. The analysis of the gaze behavior showed that driving with the system did not lead to a stronger involvement in secondary tasks.
The study supports the hypotheses about the importance of missing expectations for the occurrence of accidents. These accidents can be prevented by an FCW+ that brakes autonomously.
The results indicate that an autonomous braking intervention should be implemented in FCW systems to increase the effectiveness of these assistance systems.
In a low-fidelity, fixed-base F-16 flight simulator, 12 fighter pilots attempted to recover from unusual pitch-down inverted attitudes. Recovery was done in a control condition, aided by a heads-up display (HUD) only, and with 3 command display augmentations: (a) a command visual icon, pointing in the direction of appropriate control; (b) the icon augmented with a voice command; and (c) the icon augmented with a tactile command. All 3 command displays reduced the time to make the initial recovery response relative to the control condition, and decreased the frequency of initial incorrect roll responses. The tactile and voice augmentations also improved the speed of initial recovery response from the most severe inversions.
Tested the hypothesis that S-R compatibility is maximum when the pairings of stimulus and response elements in the formation of an S-R ensemble insure maximum agreement with population stereotypes. The pairings in this study were of maximum, mirrored, and random correspondence, and the results such as to support the hypothesis. It would appear that the compatibility effects in perceptual-motor tasks are relatively large in comparision with the effects produced by learning or amount of information relevant to successive choices. The implications for transfer of training and individual differences studies of the concept of compatibility are discussed.
This study examined the impact of semantic and acoustics parameters of in-vehicle collision warning system (CWS) alarms on driver response. Thirty participants drove a simulated vehicle through scenarios containing five different unexpected hazard events. As drivers approached the hazard event one of four CWS alarms, counter balanced with the hazard event type, or no alarm (control) was presented. Alarms consisted of the signal word “Notice” or “Danger” presented at either 70 or 85 dBA. Rear-end collision events resulted in the highest crash rate, accounting for 45.4% of all crashes. In these scenarios, CWSs significantly reduced crash rates. CWS alarms with an intermediate urgency level achieved through an interaction of semantics and acoustics (“Danger” at 70 dB and “Notice” at 85 dB) resulted in significant reductions in crash probability. Providing an extremely urgent signal word, “Danger” at a high acoustically urgent presentation level – 85 dB was not effective in reducing crashes, nor was a low urgency signal word, “Notice” presented at a low acoustical urgency level – 70 dB. Implications of these results for the design and implementation of CWS systems and auditory alarms in general, are discussed.Research highlights► Auditory collision warning system (CWS) alarms can reduce crash probability if designed to convey appropriate hazard levels. ► Semantic and acoustics parameters of in-vehicle collision warning system (CWS) auditory alarms interact to effect driver response. ► Inappropriately hazard matched auditory warnings (extreme urgency or very low urgency) are ineffective. ► Auditory warning context impacts behavioral response and ratings of perceived urgency. ► The signal word “Notice” presented at a relatively high acoustic intensity of 85 dB and “Danger” presented at a relatively low acoustic intensity of 70 dB resulted in equal crash reduction probability and were perceived as having equivalent urgency levels.
Intelligent Vehicle-Highway Systems (IVHS) have been proposed in the wake of rapid worldwide growth in traffic volume and density. These systems involve the application of advanced sensor, communications, computational, and control technologies to the design of highways and vehicles to improve traffic flow and safety. Similar technologies have been applied in other transportation systems such as aviation and air-traffic control, and it is suggested that the human factors insights derived from these systems can be usefully applied, proactively rather than retroactively, in IVHS design. Several safety and human factors issues relevant to the design of IVHS technologies, both near-term and long-term, are discussed, including: (a) the optimization of driver mental workload in highly-automated “hybrid” systems; (b) the design of in-vehicle navigation aids and the resolution of display conflicts; (c) individual and group differences in driver behavior and their implications for training and licensure; (d) the evolution and integration of IVHS technologies; and (e) traffic management and the regulation of driver trust in IVHS. Successful resolution of these issues and their incorporation in IVHS design will provide for fully functional systems that will serve the twin needs of reducing traffic congestion and improving highway safety.
One of the main contributing factors with intersection accidents is lack of information due to attention allocation. In many cases, drivers fail to yield right of way to other traffic participants. One reason is that drivers have inappropriate expectations about a traffic situation. They allocate their attention primarily to certain areas of the intersection but neglect others. In a driving simulator study, the influence of intersection complexity on drivers' expectations and their driving behavior was examined. In two T-intersections, the complexity was varied by the traffic density (low and high) using either one or two important objects: vehicles (left) with or without pedestrians (right). Additionally, the reaction to two critical incidents in close proximity of the intersections was examined. Gaze behavior, vehicle reactions, and subjective data were recorded. 40 subjects (26 male, 14 female, M=31.0 years, SD=11.9 years) participated in the study. Interestingly, the least complex intersections showed the most accidents which was interpreted as the result of inadequate attention allocation. It was shown that both the drivers' attention allocation and vehicle velocity when turning off were responsible for this effect. The results contribute to a better understanding of the role of drivers' expectation and attention allocation in the causation of intersection accidents.
Multisensory integration and crossmodal attention have a large impact on how we perceive the world. Therefore, it is important to know under what circumstances these processes take place and how they affect our performance. So far, no consensus has been reached on whether multisensory integration and crossmodal attention operate independently and whether they represent truly automatic processes. This review describes the constraints under which multisensory integration and crossmodal attention occur and in what brain areas these processes take place. Some studies suggest that multisensory integration and crossmodal attention take place in higher heteromodal brain areas, while others show the involvement of early sensory specific areas. Additionally, the current literature suggests that multisensory integration and attention interact depending on what processing level integration takes place. To shed light on this issue, different frameworks regarding the level at which multisensory interactions takes place are discussed. Finally, this review focuses on the question whether audiovisual interactions and crossmodal attention in particular are automatic processes. Recent studies suggest that this is not always the case. Overall, this review provides evidence for a parallel processing framework suggesting that both multisensory integration and attentional processes take place and can interact at multiple stages in the brain.
The last 30 years have seen numerous studies demonstrating unimodal and crossmodal spatial cuing effects. However, surprisingly few studies have attempted to investigate whether multisensory cues might be any more effective in capturing a person's spatial attention than unimodal cues. Indeed, until very recently, the consensus view was that multisensory cues were, in fact, no more effective. However, the results of several recent studies have overturned this conclusion, by showing that multisensory cues retain their attention-capturing ability under conditions of perceptual load (i.e., when participants are simultaneously engaged in a concurrent attention-demanding task) while their constituent signals (when presented unimodally) do not. Here we review the empirical literature on multisensory spatial cuing effects and highlight the implications that this research has for the design of more effective warning signals in applied settings.
Collision warning systems offer a promising approach to mitigate rear-end collisions, but substantial uncertainty exists regarding the joint performance of the driver and the collision warning algorithms. A simple deterministic model of driver performance was used to examine kinematics-based and perceptual-based rear-end collision avoidance algorithms over a range of collision situations, algorithm parameters, and assumptions regarding driver performance. The results show that the assumptions concerning driver reaction times have important consequences for algorithm performance, with underestimates dramatically undermining the safety benefit of the warning. Additionally, under some circumstances, when drivers rely on the warning algorithms, larger headways can result in more severe collisions. This reflects the nonlinear interaction among the collision situation, the algorithm, and driver response that should not be attributed to the complexities of driver behavior but to the kinematics of the situation. Comparisons made with experimental data demonstrate that a simple human performance model can capture important elements of system performance and complement expensive human-in-the-loop experiments. Actual or potential applications of this research include selection of an appropriate algorithm, more accurate specification of algorithm parameters, and guidance for future experiments.