Red Means Stop, and So Does 'X'

I'm colorblind and I run in to a lot of instances where information is conveyed by color. Occasionaly, there is additional information to help provide distinction (position of stop lights) but not always (multi-color charge LEDs). Stop lights could use a little bit more information. Most people wouldn't even think twice about it, but to some people the red and yellow and/or the red and green lights look very similar (they actually add blue to the green light to help with colorblindness). When I am unable to see the position of the light in the stack of 3, it is hard to tell yellow from red at a distance. This is worse at night as you can't see the housing of the light to distinguish position. Luckily, 4 way stops on country roads with blinking lights also include the familiar octagon stop sign.

I don't know for sure, but it seems like stop lights are round because the original light sources within them illuminated a circle well. As stoplights made of LEDs become more and more popular, it seems that we are given the opportunity to use shapes, in addition to color, to let people know whether they should stop or go.

I'm not proposing a huge change here, just suggesting that we add a simple shape within the round stoplight. The green light would include a dot. The yellow line would include a line. The red light would include an 'x'. These shapes could be made of white LEDs, or perhaps a void of light, resulting in a black shape. I wouldn't think this would cost much more, if any. You'd only need to use a different color LED, or leave it out completely. However, this minor change could add safety and clarity to a lot of people out there on the roads.