Auditory Localization of Backup Alarms: The Effects of Alarm Mounting Location

Heckman, Genevieve M.; Kim, Robyn S.; Khan, Farheen S.; Bare, Cleve; Yamaguchi, Gary T.

doi:10.4271/2011-01-0086

Cited by 4 publications

(6 citation statements)

References 9 publications

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“…Participants also performed better with earplugs compared to earmuffs, while localization performance was not improved in the level-dependent mode over that in the passive mode and at times was further degraded. Other researchers ( Brown et al, 2015 ; Heckman et al, 2011 ; Mlynski & Kozlowski, 2017 ) have also shown best localization accuracy for lateral positions (90° and 270°) compared to sources coming directly from the front and the back (0° and 180°). Further analyses of the localization data obtained in the current study yielded similar findings, in all listening conditions, of more frequent front/back confusions for signals coming directly from the front and the back (0° and 180°) and more accurate judgments for signals coming from the two side positions (90° and 270°).…”

Section: Discussionmentioning

confidence: 87%

Effect of Hearing and Head Protection on the Localization of Tonal and Broadband Reverse Alarms

et al. 2021

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Objective This study explored the effects of hearing protection devices (HPDs) and head protection on the ability of normal-hearing individuals to localize reverse alarms in background noise. Background Among factors potentially contributing to accidents involving heavy vehicles, reverse alarms can be difficult to localize in space, leading to errors in identifying the source of danger. Previous studies have shown that traditional tonal alarms are more difficult to localize than broadband alarms. In addition, HPDs and safety helmets may further impair localization. Method Standing in the middle of an array of eight loudspeakers, participants with and without HPDs (passive and level-dependent) had to identify the loudspeaker emitting a single cycle of the alarm while performing a task on a tablet computer. Results The broadband alarm was easier to localize than the tonal alarm. Passive HPDs had a significant impact on sound localization (earmuffs generally more so than earplugs), particularly double hearing protection, and level-dependent HPDs did not fully restore sound localization abilities. The safety helmet had a much lesser impact on performance than HPDs. Conclusion Where good sound localization abilities are essential in noisy workplaces, the broadband alarm should be used, double hearing protection should be avoided, and earplug-style passive or level-dependent devices may be a better choice than earmuff-style devices. Construction safety helmets, however, seem to have only a minimal effect on sound localization. Application Results of this study will help stakeholders make decisions that are more informed in promoting safer workplaces.

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Section: Discussionmentioning

confidence: 87%

Effect of Hearing and Head Protection on the Localization of Tonal and Broadband Reverse Alarms

et al. 2021

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“…Large differences in the loudness and urgency evoked by the alarm can stem from such abrupt variations in sound pressure levels, depending on the exact position of workers in the danger zone and confusions can arise in the perceived direction and distance of reversing vehicles that fall outside the visual field of nearby workers. The sound propagation behind the vehicles will also be affected by the alarm mounting location on the vehicle, thus impacting auditory perception of the alarm signal as shown recently by Heckman et al [14] These authors have found that localization of the backup alarm was strongly affected by the mounting location, most notably when the alarm stimuli originated from either behind or in front of the listener. In addition to these sound propagation issues immediately behind the vehicles, conventional (tonal) backup alarm signals can travel over distances well beyond the danger zone, resulting in noise annoyance in workers, which are not at risk.…”

Section: Introductionmentioning

confidence: 89%

“…Although interaural time differences (ITDs) aid in localizing sounds below 1500 Hz and interaural intensity differences (IIDs) allow one to localize sounds higher than 3000 Hz, high frequency (>5000 Hz) spectral cues help resolve front/back (F/B) confusions and identify the position (elevation) of a source in the vertical plane. [14,[20][21][22][23] Broadband sounds (BBS) are theoretically easier to localize as they offer a greater number of cues (IID, ITD and spectral cues) compared with sounds with a limited frequency spectrum such as conventional ambulance sirens and tonal backup alarms, which typically have a dominant frequency between 1000 and 4000 Hz, [12] a frequency region where few localization cues are available. The SAE J994 [2] standard currently states that the dominant frequency of backup alarms should be between 700 and 2800 Hz.…”

Section: Introductionmentioning

confidence: 99%

Comparison of sound propagation and perception of three types of backup alarms with regards to worker safety

et al. 2013

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A technology of backup alarms based on the use of a broadband signal has recently gained popularity in many countries. In this study, the performance of this broadband technology is compared to that of a conventional tonal alarm and a multi-tone alarm from a worker-safety standpoint. Field measurements of sound pressure level patterns behind heavy vehicles were performed in real work environments and psychoacoustic measurements (sound detection thresholds, equal loudness, perceived urgency and sound localization) were carried out in the laboratory with human subjects. Compared with the conventional tonal alarm, the broadband alarm generates a much more uniform sound field behind vehicles, is easier to localize in space and is judged slighter louder at representative alarm levels. Slight advantages were found with the tonal alarm for sound detection and for perceived urgency at low levels, but these benefits observed in laboratory conditions would not overcome the detrimental effects associated with the large and abrupt variations in sound pressure levels (up to 15-20 dB within short distances) observed in the field behind vehicles for this alarm, which are significantly higher than those obtained with the broadband alarm. Performance with the multi-tone alarm generally fell between that of the tonal and broadband alarms on most measures.

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“…Tonal alarms are used on forklifts in many industries to meet OSHA's safety requirements. However, the effectiveness of these alarms can be reduced due to ambient noise conditions, use of hearing protection, and inability to localize the direction of the sound source (Heckman et al, 2011;Lancaster, Alali, Casali, 2007;Purswell and Purswell, 2001). Increased ambient noise levels can significantly impact the effectiveness of audible alarms by reducing worker's ability to localize the direction of the alarm (Lancaster, Alali, & Casali, 2007).…”

Section: Introductionmentioning

confidence: 99%

“…Alarm fatigue due to constant alarms could also result in pedestrians 'tuning-out' backup alarms notifying the pedestrian they are in the travel zone of a forklift (Brammer and Laroche, 2012). Another concern with tonal alarms is the impact of pedestrian localization performance based on the location of an alarm on a vehicle (Heckman et al, 2011). Blue safety lights are increasingly popular method of warning pedestrians of oncoming forklift traffic and are used in conjunction with audible alarms.…”

Section: Introductionmentioning

confidence: 99%

Industrial Workers Perception of Reverse Motion Warning Devices on Forklifts

Abulhassan

Wilbanks

Kilpatrick³

et al. 2019

Proceedings of the Human Factors and Ergonomics Society Annual

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In the United States, forklift accidents account for one in every six workplace fatalities (Bostelman and Shackleford, 2010). Backup warning devices such as tonal alarms and blue safety lights are commonly used to alert pedestrians of approaching forklifts. The purpose of this research is to identify worker’s perception on the effectiveness of two configurations of backup alarm systems: the level of nuisance perceived of these systems; and the importance of having a forward motion warning system. Results of this study indicate no statistically significant differences in the level of satisfaction between facilities using tonal backup alarms and facilities that use both tonal backup alarms along with blue safety lights. Additionally, results of this study indicate that the majority of the pedestrians and forklift operators sampled are in favor of having forward motion warning devices installed on forklifts.

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Auditory Localization of Backup Alarms: The Effects of Alarm Mounting Location

Cited by 4 publications

References 9 publications

Effect of Hearing and Head Protection on the Localization of Tonal and Broadband Reverse Alarms

Effect of Hearing and Head Protection on the Localization of Tonal and Broadband Reverse Alarms

Comparison of sound propagation and perception of three types of backup alarms with regards to worker safety

Industrial Workers Perception of Reverse Motion Warning Devices on Forklifts

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