From the NHTSA via the Consumer Reports Car blog:

Turn signals: amber vs. red
A new report from the National Highway Traffic Safety Administration [NHTSA] has found that amber rear turn signals are 5.3 percent more effective than red signals in reducing crashes. The real-world study looked at rear-end crashes where the front vehicle was in the act of turning, merging, changing lanes, or pulling in or out of a parking lot.

I've always been a fan of amber signals for increased noticeability and I've been bothered to see some move back to red in recent years (especially from American car companies). I wonder if this will swing the pendulum back to amber signals. (Not that 5.3% is huge, but I LIKE to be noticed when I'm changing lanes or turning.)

 

I agree 100% Also I think they look better. I believe it is the law in Europe and Asia that rear turn signals must be amber which is why you see them on "foreign" makes.

 

I agree about amber rear turn signals. A lethargically pulsing red brake light is poor, in comparison.

Something else that bugs me: front turn signals tightly integrated with the headlights, most typically a thin strip running under the headlight. Sometimes these are near impossible to discern, due to their proximity to the bright headlight: they can be a menace with oncoming cars/trucks which may or may not be turning left in front of you.