Instead of the BEEP BEEP BEEP BEEP,
Why not a little melody? Keep the beeps, but make they play a song or something.
Or a computerized voice that's saying, "Backing up, move it, get out of the way?"
How about a little classic rock? That gets your attention. Although, I feel that could have logistical problems. Whatever, throw the concept to your R&D Department... that's why you pay the engineers the big bucks!
I mean, I get that it has to be loud so you can hear it, but I think it could be just as noticeable if it anything else as long as it's as loud.
Work it out people!