Narrator: This is Science Today. Cars in general are all becoming quieter and while this is a good trend in terms of noise pollution, cognitive psychologist Larry Rosenblum of the University of California, Riverside, says quiet engines are harder for blind pedestrians, as well as the elderly and children, to hear.
Rosenblum: Noise pollution is a very serious issue and if you talk to the blind community, they'll tell you the exact same thing. They want the world to be quieter as well, but they want the world to be quieter so they can hear the important things and this is one thing that they need to hear.
Narrator: Rosenblum has spent years researching how the brain reacts to approaching sounds, and recently discovered in a study funded by the National Federation of the Blind, that hybrid cars are very hard for the blind and other pedestrians, to hear.
Rosenblum: I think that adding a quiet noise to hybrid cars when they're going very slowly would probably solve the problem well. One thing that's good about the fact that our brains seem designed to be especially sensitive to approaching sounds is that we don't need a lot of sound to activate those parts of our brain.
Narrator: For Science Today, I'm Larissa Branin.