Hybrids, electric cars may be too quiet, says DOT

The U.S. Department of Transport has become the latest group to look further into noisemaking devices for electric and hybrid vehicles.

Several pressure and safety groups have proposed such devices in the past, reasoning that the silent nature of cars using electric power at low speeds would prove a risk to pedestrians.

The DoT's National Highway Traffic Safety Administration (NHTSA) is proposing a minimum sound standard for hybrid and electric vehicles, which would require them to produce a noise detectable under 18 mph.

"Safety is our highest priority, and this proposal will help keep everyone using our nation's streets and roadways safe, whether they are motorists, bicyclists or pedestrians, and especially the blind and visually impaired," explains U.S. Transportation Secretary Ray LaHood. 

For many owners, an electric or hybrid vehicle'slow-speed silence is one of its greatest virtues.

Yet, as the number of electrically-propelled vehicles has increased in recent years, some groups have been putting pressure on carmakers to attach noisemakers to their vehicles, making it easier for pedestrians, and particularly the visually-impaired, to detect an approaching vehicle.

As yet, there's been little conclusive evidence that the silence of electric and hybrid vehicles is a contributing factor in accidents--nor that existing, noisier vehicles are safer, despite thousands of pedestrians worldwide being injured or killed each year by internal combustion vehicles.

The NHTSA says that carmakers would have the freedom to pick their own noise, but this noise would have to meet certain requirements in order to be audible.

The Administration predicts that there would be 2,800 fewer pedestrian and cyclist injuries over the life of each model year of electric and hybrid vehicles as a result of the noise-making devices.