Audible pedestrian traffic signals: Part 3. Detectability.
This project (10) evaluated audible pedestrian traffic signals (APTS) from three perspectives: 1) the patterns of use and the impact of these signals on pedestrian travel; 2) the physical characteristics of the sound emitted by the Nagoya/Traconex APTS; and, 3) the detectability of the sounds emitted by this brand of APTS. This paper, the last of three companion articles (13,14), describes the detectability of the sounds emitted by the Nagoya/Traconex audible traffic signal, the unit most commonly found in the western United States and almost exclusively in California. To determine detectability, three groups of subjects with normal hearing--young sighted adults (controls), elderly sighted adults, and elderly blind adults--participated in an audiological study. Auditory stimuli, which consisted of APTS sounds embedded in various levels of interfering traffic noise, were presented to subjects seated inside a double-walled sound-treated chamber. The subjects were instructed to press down on a response button as soon as they heard the audible pedestrian traffic signal. The percentage of correct detections determined the absolute detectability of APTS under various S/N ratios. The subjects' speed of response indicated how quickly a pedestrian might begin to cross the intersection upon hearing the APTS.
Szeto
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Department of Electrical Engineering, San Diego State University, CA 92182-0190.
Valerio
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Novak
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D000063:Accidents, Traffic / Q000517:prevention & control*; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001307:Auditory Perception; D001309:Auditory Threshold; D003143:Communication Devices for People with Disabilities / Q000592:standards*; D005069:Evaluation Studies as Topic; D006309:Hearing; D006801:Humans; D009622:Noise / Q000009:adverse effects; D013018:Sound Spectrography; D014786:Vision Disorders / Q000534:rehabilitation*