Really sorry to hear about your accident, and I hope you recover quickly and get back on a scoot soon...
That being said, I don't think the loudness of your bike in this situation would have helped you at all... I have VERY loud pipes, and people still don't see me... Granted, I believe that the loud pipes help in thicker traffic, but in your situation, don't think it would have helped at all.
I have loud pipes, only because I wanted loud pipes!!
Good luck