What tint colors are most useful for cycling sunglasses? There seem to be a lot of different lens options for sunglasses, and there must be objective differences. For example, I've seen golf lenses advertised as filtering out blue light to improve reading of greens, but this would not seem to have any benefit for cycling. What particular tint colors are most useful for cycling sunglasses?

Would it be adequate to stick to neutral-colored filters (which would presumably be ideal for enjoying the scenery), or do any particular colors provide a significant advantage? Do photochromic (a.k.a. photochromatic or Transitions) lenses vary the darkness ideally, or is it really better to have multi-lens glasses with a few different colors?

Related questions: Sunglasses for commuting? (which asks for recommendations for brands/models of sunglasses), What are the features that I should seek in cycling glasses? (which asks for which features are desirable in general)
There are many factors that influence choices. -  terrain you ride, sunlight intensity, shade effects etc, and personal preference. A quick internet search will give you technical answers on what colors do look here . 

For me personally, I mostly Mountain Bike, I live in New Zealand, which has extremely high UV light levels. Therefore I do not venture out for more than an hour without some protection. I will use different glasses for different rides, but only because I have them. For use while riding, the all rounder is Yellow, for other things as well, I would head towards amber. If correct color perception is important, then you will struggle to get glass that work as well as Yellows/Amber's - especially in low light.   

The advantage of the blue filters (blue blockers) is they lift depth perception and contrast - maybe roadies don't need it, but off road MTB it is a definite advantage.   

Clear - I use these where protection from things other than sunlight is desirable (insects, sticks, dust etc), and maximum use of available light essential - mostly night riding. 

Yellow - I use these a majority of my riding. Do a great job at smoothing the transition from shade to full sunlight (i.e. I can see into dark forest from bright sunlight). On bright days, let too much light in for comfort (But still protect from damaging UV). Mine are specific sports style - not really a fashion accessory.... 

Amber - Similar to yellow, but filter more light, making the shade a bit darker. Probably my most versatile sun glasses - use them when the yellows will look dorky -rides with family, beached etc. 

Blue/polarised -  Better color perception so I use the driving, fishing and general wear. Mine are pretty much towards the "fashion" end of the style range, not good for riding - too dark for forests.