A "traffic light" is also the name of a cocktail, consisting of three layers. Making them is not really easy, since you have to pour three different drinks into a glass, without mixing them.

First, fill 30% of the glass with red berry liquor. Here in Holland they sell it, but I don't know about other countries. Of course you can try it with other red liquors.
Then carefully pour orangejuice on top, so that it won't mix. This can be accomplished by holding a spoon in the glass and slowly pouring the juice on it. Fill the glass with orangejuice until about 60% of the glass is full.
Finally, add Pisang Ambon, a green liquor with banana-taste. Pour this in the same way you did with the orangejuice: very carefully. Don't fill it to the top of the glass, or else you can't add ice.
If you do it right, you can see three layers in the glass.
Put in a straw, and enjoy.