Flaser int he rear it he US can be red. take a loo at most any ford, or GM truck made, as well as many other ford's and chevy's..
Most had all red taillights. I believe the new caddy's do too.
As long as its visible in the rear it should be legal in the states... But it has to be red or orange to be considered legal.
Though I haven't had any issues with mine using clear bulbs at all front and rear... yet.
'92 300CE - Sold
2004 C240 - C7 Wheels
2015 ML350 - P1, Pano, Ash poplar wood, Sport Dinamica interior, Running Boards Keyless go.