One thing we read everyday and dont even know about it. Without these signs we more than likely couldnt get around town and know where we are going. I have been lost before driving in unfamiliar places and these road signs helped me out a lot.
What is the speed limit? It is hard enough going the speed limit now you have to figure it out too? What if you solve it wrong? All the people who never took algebra would be getting a lot of tickets. The answer is 45 mph.