Effect of artificial alert sound, background noise, and vehicle type on: Detectability and localizability of quiet cars by blind pedestrians

Blind pedestrians use traffic sounds to align when crossing a street, identify when to cross, correct veers while crossing, and know vehicle paths. Hybrid electric vehicles are quieter than internal combustion engine (ICE) vehicles, especially when starting from a stop, moving at slow speeds, backing up, and decelerating. A looped traffic recording was played to a group of four or five participants through loudspeakers in an empty parking lot. A sound level meter stood behind the center participant. No significant difference was found between the low and medium or the medium and high vehicle sound levels. Detection distance at the low background sound level was twice as far, on average, than at the high background level. Detection distance for ICE vehicles was not different from that for VSP vehicles. ICE vehicles decreased surge detection time as the vehicle sound level increased in both low and high background sound levels, but VSP vehicle data remained relatively flat. For the percentage of surge misses, there was no significant difference between the vehicle sound levels under either the low or high background sound conditions.