The use of auditory icons in commercial truck cabs has the potential to increase the number of auditory displays that can be distinguished and understood by commercial vehicle operators, and this experiment sought to determine the utility of auditory icons in that situation. Nine auditory icons were evaluated by commercial vehicle operators as they drove an experimental vehicle over public roads. A comparison of the data collected in the truck-cab environment to data collected in a laboratory study on the same auditory icons revealed some differences in the perceived meaning, perceived urgency, and association with the auditory icons' intended meanings between the two conditions. The presence of these differences indicates that driver evaluations of auditory icons can be affected by the environment, and testing should therefore be conducted in a situation that approximates the end-user environment as closely as possible. This technical report describes an investigation of auditory icons within the domain of commercial motor vehicles.
Auditory icons are representational sounds in that they have specific, stereotypical meanings.
While typical non-verbal sounds are defined by their particular acoustic parameters, auditory icons are defined by the object or action that created the sounds. Attention was focused on the auditory icons' perceived meaning and perceived urgency in an attempt to reduce the influence of experimenter bias in the auditory icon selection process. Fifty-one auditory icons were evaluated on the basis of perceived meaning, urgency, and association of task with an expert opinion. After an extensive literature review on topics related to hearing and driving, a human factors engineering approach was used to evaluate the appropriateness of this hearing requirement, the methods currently specified to test drivers' hearing, and the appropriate hearing levels required. Task analysis, audiometry, dosimetry, in-cab noise measurements, and analytical prediction of both speech intelligibility and masked thresholds were all used in performing the evaluation.