The silent Prius

I rode in a Prius recently and was intrigued that it is silent during certain phases of operation. I was wondering if this is a safety hazard, because pedestrians, kids, dogs, etc. can’t hear it coming?

of course it can be…see this web site…
http://www.thecarconnection.com/tips-article/1010548_blind-want-prius-to-make-noise

They can hear the wind noise and the noise of the tires. Besides, the engine is off only at low speeds. If you see a pedestrian on the road and the engine is off, you should have enough time to brake or honk the horn.

Yes. Advocates for the blind and deaf are trying to have some sort of warning noise mandated for electric cars.

I don’t see how a warning noise would help the deaf.