It's funny that you posted this because when I was 15 getting my learners permit to drive that was the one and only question that I missed. And if you miss one road sign you fail the whole thing and have to come back another day. I knew what the sign ment! It means no right turn! Me being dyslexic haha I chose no left turn! Haha I know my left from my right I just got excited nervous whatever you call it and messed up! Hahaha but that sign means no right turn! Its usally at an intersection where the adjacent street is one way!