People affected by color blindness do see a difference between the little green man who is walking and the red man who waits to turn green. Maybe the difference is not the same difference as you can see it, but there is a difference.
For my colorblind eyes the first and the second pictures are similar and the third is almost the same again. Only the last one is definitely different. It looks more like a grayscale picture to me.
 |
 |
 |
 |
Photos taken by J. Ignacio Stark – 
Some rights reserved.
The photographs are shown in the following order: Normal – Protanopia – Deuteranopia – Tritanopia. Choose the one which is most suitable to you.
Related articles:
At the Traffic Light
5 Misbeliefs about Color Blindness
That’s pretty cool. The two in the middle look purple-ish to me. The first and last look alike, except the first one is red and blue and the last is red and green