As a driver of a Civic hybrid, I am used to the stunned reactions of people jumping out of the way as my car glides silently behind them across a parking lot when the gasoline engine shuts off. The Toyota Prius uses a back-up beeper to alert the driver as the car runs solely in electric mode in reverse.
The US Army is funding the development of a prototype military hybrid vehicle that will use the silence of electric drive in developing a diesel hybrid electric version of its Alternative Mobility Vehicle (AMV) "Aggressor."
Some benefits of the vehicle are a silent mode for patrolling, a 0-40 mpg acceleration in 4 seconds and improved fuel economy. Quantum Technologies
While it's true that I've surprised my share of unsuspecting pedestrians while silently gliding through the parking lot in my Prius (ahhh, the joys of hybrid ownership!), I don't think the back-up beeper on the Prius was designed to warn anyone other than the driver --it can't be heard from outside the car (or at least not very well).
My theory is that Toyota put it in to warn the driver that the car is in reverse due to the fact that the shift knob automatically toggles back to it's rest position once a selection is made and the knob let go. If it didn't beep, a person might accidently think the car was in drive because visually, the knob returns to the same position whether "drive" or "reverse" was selected. Kinda quirky but you get used to it.
I stand corrected. The one I test drove beeped, but yeah, i guess it was in the dash and come to think of it I have never heard one beeping in a parking lot.
You can also shut off the beeper with some dash switch sequences, i believe.
I remember reading somewhere that the British government was trying to figure out if fuel cell (electric) motorcycles should emit artificial motorcycle noises to warn peds.
Yeah, you can shut the beeper off, but I haven't bothered.
Boy I sure hope they don't start putting noise makers into hybrids. Part of the joy to driving one is the sweet sound of silence.
Yes... a consortium of anti-hybrid automakers and Exxonmobileshell will pay congress to pass a law requiring all hybrids to emit the sound of a 1984 Cavalier with 150k on it... ha