Speaking of colors - you would expect that someone(s) does a comprehensive, extremely detailed study based upon surveys, tests, experimental models, etc. Either that, or they just spin a wheel.
From a purist POV, you'd lean towards black / silver / white / red / BRG / dark blue / tan / burgandy, and so on.
Beauty is in the eye of the beholder of course, but for instance baby blue / pink / brown / gold for example may not look too great on a bike.
Also of interest is how many otherwise good car colors do not translate well to bikes. You can easily "date" a vehicle by choosing a trendy color, if that color turns out to be unpopular, and is dropped soon from the line-up. "Copper" is a color I've seen lately on cars and SUV's, that may end up as billboards saying "Late 2000nds".
"Speedtrip Brown"

IMHO, is one color that doesn't seem to work well on either. My personal vast and comprehensive research on this subject, having spent over 1.5 minutes pondering the issue, results in black being the new... black, which is also the fastest color by the way. Just sayin'.
Ride Safe (and colorfully)!
Bob