The National Highway Traffic Safety Administration wants to pass a new rule that would require some cars to make more noise, specifically those silent electric and hybrid vehicles.

Jamie Kitman, the New York bureau chief of Automobile magazine, remembers test driving the very first Tesla, an electric sports car, when he saw two guys about to cross the road in front of him.

"I was thinking: 'God these people are pretending they don't even hear me coming,' and sure enough right as I was about to run them over, they turned with a start and ran," says Kitman.

That problem is expected to grow as more electric cars hit the road. The new rule is in a public comment period. It would require automakers to add some kind of sound that the cars emit at low speeds, loud enough for bicyclists and pedestrians to hear. Kitman says the sound could be customizable.

"There's no reason your car couldn't sound like Rush Limbaugh or Rachel Maddow or Led Zeppelin," he says.

Most likely, the car companies will choose something that sounds like a traditional car engine. That's not too far off base from what they already do, says Michelle Krebs at Edmunds.com. She points out that many cars already have artificial mechanical sounds, added to enhance the driving experience.

"When you're driving a performance car, they can tune it to sound really gutteral or throaty," says Krebs.

But most electric and hybrid car drivers like that their cars are quiet. So expect whatever sound the car companies choose to be subtle.