I would avoid emerald green on a Subaru or probably any car, because I think that color is not as visible as other colors; although it does depend on the environment. I might want a black vehicle during constant snow conditions, or a white car otherwise, generally, except during heavy snow conditions. It seems to me that a car with two tones, contrasting each other, that both reflect light well, such as mostly silver with some black, or yellow and black, especially if the two tones are vertical (side by side) as well as horizontal. I think yellow taxicabs are probably good examples of being highly visible, because of the high intensity yellow with the contrasting letters, decals, etc, as well as black tires adding to the contrast. I also think that darkly tinted windows on a light colored vehicle help with contrast. The other day, I saw a small, black car with darkly tinted windows, and black wheels and tires, and I did not notice it until a gleam of reflected sunlight bounced off of it and hit my eyes. It seems like white or silver might be good, because they reflect a lot of light that hits the eyes of other drivers. Maybe a lot of chrome is also good for visibility. To summarize, I would want colors in the cooler end of the light spectrum (white, silver, yellow) with high intensity and contrasting tones, and other aspects of good light reflection (shiny, clean surfaces, chrome, glass).
There appears to be something you are all missing about what is the safest car colour. My problem is when my car is stationery, either in a car park with or without myself in it and even pulled up behind another vehicle who decides to reverse into me for no apparent reason!!! This is our first green car we have owned and we have never owned a car like it for getting scratched, dented and down right smashed into all while stationery. Older motorcycle riders may know that green is actually a superstitious colour to have a bike in for this fact - but I would like to know the statistics for “stationery” crashes sorted by their colour! hmmm food for thought do you think?