Towards the bottom of the article is a picture titled "The road to a better, better parking sign" that shows various iterations of the design. It isn't very clear, but if you look closely at the two iterations on the right there are stripes added to the red specifically for color blind.
I was about to make the same comment. It's really hard to distinguish between those two colors as implemented on the sign. Green and red colors by themselves are okay but there should be another clear identifying characteristic like shape, outlining etc.
In English, "America" is nearly always synonymous with "USA".
If GP meant "North and South America", he would have said "the Americas" instead. I understand this is different in other languages which I imagine must be confusing and arrogant-seeming for those with English as a second language.
