One of the best features of hybrids, besides the economic and environmental benefits, is that they don’t make much sound. It’s nice to not hear the growl of an engine. However, President Obama made his opinion known by signing the Pedestrian Safety Enhancement Act of 2010 which will eventually require hybrid vehicles to make a sound so that children, the visually impaired and all pedestrians will have the ability to hear hybrids as they approach at slow speeds.
It is a very obscure and flexible law, merely directing the Secretary of Transportation to “study and establish a motor vehicle safety standard that provides for a means of alerting blind and other pedestrians of motor vehicle operation.” As I read it, this means the Secretary has the freedom to explore this as an option at some point, with no firm deadline.
Here’s my two cents, what if hybrid manufacturers had to choose from a set of pre-approved classic rock songs to play? Then you could be walking down the street and hear ACDC’s Back in Black coming down the road and know you shouldn’t step out into the street because a hybrid is coming. Source