Electric vehicles are really, really quiet, which is nice - unless one sneaks up on you in the parking lot and scares the bejesus out of you. Not to worry, our legislators have come up with, um, legislation that electric vehicles should make some kind of noise when traveling up to a certain speed (forward or backwards).
Above that certain speed (19 mph, for some reason), road and other noise should be sufficiently loud that the artificial noise will not be needed. One can only hope the manufacturers might allow sound options (tractor, choo-choo train, bulldozer) rather than just dumb old car engine noises.
There is a more serious side to this of course, if you are visually impaired to any degree and are trying to cross the street or otherwise navigate around eerily quiet electric motor vehicles.
Consumerist“We all depend on our senses to alert us to possible danger,” said U.S. Transportation Secretary Anthony Foxx. “With more, quieter hybrid and electrical cars on the road, the ability for all pedestrians to hear as well as see the cars becomes an important factor of reducing the risk of possible crashes and improving safety.”