Federal Register | Federal Motor Vehicle Safety Standards; Transmission Shift Position Sequence, Starter Interlock, and Transmission Braking Effect Looks like the Feds were considering requiring HEVs to creep backwards when you had no foot on the gas and in reverse. Toyota argued that they could inform the driver in other ways that they were in Reverse other than redesigning their software to allow a backwards creep. Toyota (and Honda) was trying to change the law that prohibited using the starter when in gear. (I know my 1989 Corolla could move by starter alone) [Edit: Is it just me, or is there no 'general Prius information' forum?]
But my Prius does creep in reverse--quite agressively. I can understand another rationale and that would be that since the "gear" selector does not remain in a discernable position the beep gives an additional cue that all is not "normal" (in Drive).
Whatever the rationale, I should be grateful for the reverse beep. If it hadn't existed, I never would have found PriusChat (by Googling "disable reverse beep 2006 Prius" the day after I brought home my Gen II). Think of all the fun I would have missed! I still have it disabled, and keep a copy of the instructions in the glove compartment. I was in someone else's Pri recently and checked my seatbelt when his reverse beep started...
