Comparison of detection threshold measurements and modeling for approaching electric cars and conventional cars presented in traffic and pink noise

This study investigates the difference in audibility of an approaching conventional car with internal combustion engine and an electric car at various velocities. The goal was to compare the risk that pedestrians do not hear the approaching car in time. Binaural recordings of each of these approaching cars were presented together with either a traffic noise masker or a pink noise masker. In the first detection experiment, the threshold level was determined for which the cars could just be detected. In a second reaction time experiment, the moment was determined at which the approaching car was first detectable. This measured reaction time should give an indication about how much time a person has to evade an impending collision. Results indicated that slowly approaching electric cars where less audible than cars with a conventional engine. The results also showed that the decrement of reaction times as a function of SNR was halved when pink noise was used instead of traffic noise. A psycho-acoustic masking model [Dau et al., J. Acoust. Soc. Am. 99, 3615–3622 (1996)] was applied to predict detection thresholds and showed good correspondence with the subjective data.