Shadow toll

Okay kiddo, so let's say you have a toy car and you want to race it on a big road that your dad built. But your dad doesn't want you to pay the money for using the road (like a toll road) because he wants other people to also use it without paying. So, he asks a company to take care of the road and makes a deal with them.

Now, this company gets paid by counting the cars on the road that you and other people use. It's like they are counting the shadows of the cars that pass over certain parts of the road. These are called "shadow tolls."

So, the more cars that use this road, the more money the company gets paid by your dad. This helps your dad maintain the road and keep it safe for everyone to use.

In summary, a "shadow toll" is a way of paying for using a road based on how many cars use it, without people having to stop and pay a toll fee every time they travel on it.