Hybrid Vehicles: Silent Dangers?

Those lovable, fuel-saving hybrids might not be so angelic after all. Turns out hybrids could be . . . too quiet. Perceptual psychologist Lawrence D. Rosenblum warns that hybrid electric vehicles could threaten the safety of pedestrians who can't hear the hybrids approaching. Rosenblum made an impression on Scientific American writer Sarah Simpson, who participated in his studies. In one experiment, blindfolded subjects listened to recordings of oncoming vehicles. The subjects could hear an approaching internal-combustion engine from 36 feet away. The hybrid, running in electric mode, wasn't perceived until it was 11 feet away, which would allow a person only seconds to react. Results were more dramatic when background noise was present. While there is no evidence that hybrid cars are involved in more pedestrian accidents than conventional vehicles, Rosenblum advocates adding noise to hybrids to make them more audible.

What type of sound should be added to the hybrid? Tell us what you think!

Sources:  Scientific American, National Federation of the Blind, Discovery