They're green, fuel efficient.
But too quiet and a potential threat to cyclists and pedestrians -that's what the Department of Transportation says about hybrid and electric cars.
The federal agency just proposed rules that would require new green vehicles make sounds loud enough to alert pedestrians and cyclists like George Abbott.
"I have experienced going alongside them and not realizing that there was one there," Abbott says.
It's what's under the hood that really makes these electric and hybrid cars run so quietly on the road.
This Nisean Leaf already has technology similar to what the government wants in all hybrid and electric cars. Hear that sound? The government thinks it could save lives.
Eddie George sells the vehicles at Darscars in Maryland.
"The car is very quiet, you cannot hear anything so you have some people when they come in test drive the cars, is the car on," he says.
But a flip of a switch and its pedestrian alert feature turns on. Without the feature, it's a much quieter drive. "I think that would help, but I think you know again people just need to pay more attention."
DOT says the sounds would need to be loud enough to still be heard despite other street and ambient noises when the vehicle is traveling under 18 miles per hour.
The National Highway Travel Safety Administration estimates the proposal would mean 2,800 fewer pedestrian and cyclist injuries per year.
Each company will decide what sound they want their cars to make.
The Nissan Leaf developed the sound for their vehicles with the help of students who are hearing impaired.