I didn't learn about this in driving school. Stop says the red light, go says the green. What says the yellow light, twinkling in between. Kneel says the demon light with it's eye of coal. Sauron knows your license plate and stares into your soul.
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.