May I suggest that the reason that green is used for night lighting isnt so much the eye sensitivity, tho that IS true. It has to do with persistance of vision. Green can be easily seen at night while preserving your night vision. Brighter colors like yellow kinda mess-up your night vision. Green is more "friendly" to your night vision. Some car instrument panels (speedometer, etc) are lit in yellow. While that is easier to see it is hard on your night vision. This may not be true for everybody, but it is generally true for most people.