I am going to trust the Europeans on this one. My hunch is that red in such a small form factor won't be as visible as amber, so amber it is. It will match the amber reflectors on my headlights.

http://eosweb.larc.nasa.gov/EDDOCS/W...or_Colors.html
It would appear that amber (orange) has a shorter wave length then red and is thus easier to see.