Audibility of Train Horns in Passenger Vehicles

摘要

Studies of accident rates associated with train horn bans indicate that motorists rely on horns to warn them of approaching trains. However, researchers have not yet established the levels of horn sounds necessary for detection at railroad crossings. The purpose of this study was to obtain baseline measures of the auditory component of the motorist's detection task. Horn sounds recorded in three test vehicles were presented to 20 normal-hearing listeners in quiet and in four types of vehicle interior noise: engine idling, ventilation fan off; engine idling, fan on; vehicle moving at 30 miles/hr (mph), fan off; and vehicle moving at 30 mph, fan on. Thresholds of the horn sounds were determined by an adaptive procedure. Mean thresholds were lowest in quiet (1.8-4.4 dBA) and highest for the 30-mph, fan-on condition (49.7-58.4 dBA). Mean horn thresholds for all 12 noise conditions were more than 10 dB below the overall level of the vehicle interior noise. Our data are compared with those of previous studies and their implications are discussed. Actual or potential applications of this research include the establishment of a lower limit of signal-to-noise ratios required for the detection of horn sounds at highway-rail crossings.