Turn signals and back-up lights...

In North America, rear turn signals can be amber or red. You see cars with amber turn signals all the time. NHTSA has studies that indicate there is a significant overall safety improvement with amber turn signals (e. g., http://www-nrd.nhtsa.dot.gov/Pubs/811115.PDF). It makes sense to me. :) I'm more interested in how to handle things cleanly for a back-up light.