Originally Posted by YYZ-E55

The color and specific output requirements for the rear turn signals differ between the EU and NA. Rear blinkers in the EU must be amber. For NA, they can be amber or red, but if they are amber, they must meet a specific brightness requirement that is at the high end of the EU scale (the requirements overlap slightly, but in general NA requires brighter indicators).

NA regulations also stipulate a larger surface area for the rear blinker than EU. This is why you see cars like newer Audis where the signal light uses a totally different area of the lens in NA versus EU.

Finally, it was assumed that Americans had a preference for red rear blinkers, especially on SUVs/Trucks. For the most part, Benz's with LED rear blinkers are red in NA, though a noteable exception is the facelift R-Class, which gets amber LED rear blinkers globally.