"The future isn't what it used to be." Yogi Berra
In the future, when all of the noisy pollution spewing automobiles are obsolete... and illegal, a goodly number of pets, children, and other innocent pedestrians (and bicyclists) will fall victim to electric cars, simply because the electric motor is so quiet and stealthy.
The time will come when all electric vehicles will be required to emit a safe decibel level of sound when in operation in order to protect the unsuspecting public. And, according to market trends, we'll have a choice of big brother approved sounds to personalize our fancy futuristic rides, in the same manner customized ringtones are available today... for a price, with hundreds of different audios available to satisfy our individual taste. Among the most popular will be jalopy, muscle car, galloping horses, Jetson's space car, Fred Flintstone's twinkle toes, and even Harley Davidson, (hopefully a toned down version of the latter).
"When everyone lives in the future, the present is au revoir." A Resident