Seems the NHTSA/DOT requires red & white on all large commercial trailers.
This article describes proper size, placement, etc.
http://www.seton.com/blog/2014/01/reflective-tape-regulations-what-you-need-to-knowSo, I've removed the yellow/black tape and bought some DOT approved red/white.
I understand what some replies have said about some people on the road running into emergency vehicles with their lights flashing. As someone said on a late night show - you can't fix stupid...
In any case, NHTSA/DOT says the reflective tape reduces trailer collisions by 29%. I'll take that over a nice looking back-end that I can't see anyway.