Audible pedestrian traffic signals: Part 3. Detectability.

Area of Science:

• Human Factors Engineering
• Auditory Perception
• Assistive Technology

Background:

• Audible pedestrian traffic signals (APTS) are crucial for pedestrian safety, especially for visually impaired individuals.
• The Nagoya/Traconex APTS is widely used in the western United States, necessitating an evaluation of its sound detectability.
• Previous research has explored APTS usage patterns and sound characteristics; this study focuses on detectability.

Purpose of the Study:

• To assess the detectability of sounds emitted by the Nagoya/Traconex APTS.
• To determine how varying levels of background traffic noise affect APTS sound detection.
• To evaluate the response time of different demographic groups upon hearing the APTS.

Main Methods:

• An audiological study was conducted with three subject groups: young sighted adults, elderly sighted adults, and elderly blind adults.
• Subjects listened to APTS sounds embedded in different levels of simulated traffic noise within a sound-treated chamber.
• Detection accuracy and response speed were measured to quantify APTS detectability and reaction time.

Main Results:

• The percentage of correct detections was calculated to establish the absolute detectability of APTS across various signal-to-noise (S/N) ratios.
• Response times indicated the speed at which participants initiated action upon hearing the APTS, reflecting potential crossing behavior.
• Elderly blind adults demonstrated a capacity to detect APTS sounds, though specific S/N ratios and noise levels influencing this require detailed analysis.

Conclusions:

• The detectability of Nagoya/Traconex APTS sounds was quantified under various noise conditions.
• Findings provide insights into the audibility of APTS for diverse pedestrian populations, including the elderly and visually impaired.
• This research contributes to the understanding of APTS effectiveness in enhancing pedestrian safety and accessibility.