Psychological evaluation of auditory warning signal for train horn

Abstract

Air horns are commonly used to signal danger or caution during railroad operations. The main objectives of those auditory signals (i.e., whistle cords) are to "warn of danger," "call attention," and "notification of approach" in the situation before an accident occurs or "report an emergency" to those around after an accident occurs. Further, in case of using auditory signals in nonemergency situations (e.g., during the departure or arrival of a train), loud or unpleasant sounds should be avoided to the greatest possible extent, considering noise pollution in the environment. This study examined the nature of auditory signals for railroad vehicles through psycho-acoustic experiments using 11 types of auditory stimuli, including a "short, rapid horn sound" and a "long, slow horn sound." In the rating experiments, the auditory stimuli were presented via headphones to individual participants. The results indicated that upon initiating the auditory signal with an electronic horn sound (less unpleasant and dangerous impression) before blowing the air horn to alert perceived danger, the impressions of "warning," "caution," and "danger" tended to decrease, whereas those of "pleasantness," "quietness," and "relaxedness" tended to increase. The combined usage of electric and air horns can effectively provide auditory signals for maintaining the safety of railroad operations while addressing the associated noise pollution.