One of our staff members recently had an experience that pointed out the downside of silent-running hybrids. He almost got hit by a hybrid car backing up in a parking garage that he couldn’t see or hear. Read his account of the tale here.

Full-hybrid cars that drive at low speeds on electric power without starting the gasoline engine (as well as battery electric and fuel-cell vehicles) can pose a hazard to pedestrians who can’t see or hear them, as his experience illustrated.

The issue of silent hybrids has been percolating for years. The National Federation of the Blind asked the National Highway Traffic Safety Administration (NHTSA) in 2008 to devise a standard requiring that cars be required to make some noise when they are moving. NHTSA is studying the issue.

Last week, Nissan made a proposal to NHTSA for how hybrid and electric cars should sound. The company plans to introduce its first production electric car, the Leaf, next year. Nissan has been studying what kinds of sounds electric cars should make, and it has consulted music composers in an effort to find more pleasant solution than just beeping. “We decided that if we're going to do this, if we have to make sound, then we're going to make it beautiful and futuristic," the company’s sound engineer, Toshiyuki Tabata told Bloomberg News   

In the end, Tabata and his team settled on a high-pitched sound reminiscent of the flying cars in the 1982 sci-fi classic film "Blade Runner." The sound would come on when the car starts and continue until it reaches about 12 mph, when even electric cars make enough tire noise that pedestrians can hear them.

Whatever sound is used, it needs to be a defined and standardized sound that is identifiable as a car in motion. Random sounds and tunes could be misidentified. We are looking to NHTSA and the SAE to step forward in this potential safety issue.

What do you think would be an appropriate way for silent cars to warn blind or unsuspecting pedestrians?

—Eric Evarts