Mastermind

I was waiting for a taxi on the street corner that suddenly a car stopped in front of my feet. Before I speak, he opened the front door and said: "Get in". I looked in the car with wonder and saw Hosseinqoli Khan (an old friend).
When he drove the car, I saw a written sentence on the front of the car dashboard: "60 h - 90 H 120 C", I didn’t understand what that means, inevitably I asked: "Mr. Hosseinqoli Khan, what do you mean by this sentence at the front of your car? I can’t understand it."
He changed the gear with laugh and said:
"You do not know what it is! A world of wisdom lies in it! ... "
I said: "For example?" He said: (60 h) means the result of 60km speed is home. In fact, "h" is the abbreviation of home. (90 H) means the result of 90km speed is Hospital! ... And God made a good pass. At the end, (120 C) means the result of 120km speed is the cemetery. It means that if you want to get rid of this world and its faithless people, always drive over 120km. Now, did you find out why I am saying this sentence is fantastic?! … Because every time I feel that my feet is heavy on the car gas, immediately I look at this sentence to ensure myself and pedestrians and the other vehicle drivers! ... I took a deep breath and said: "Mr. Hosseinqoli Khan, what a fantastic mastermind. I've never seen such an idea anywhere. But if I were you, I would make a cheesy cliché from this sentence and give it to a publication and tell them to print it in a large number and give to car owners for free so that they attach it on the front of their car dashboard. Because there is a three-variable equation in this sentence and it will robust mathematics and it is a world of advice too. Who knows?! Maybe police department that couldn’t solve this problem for years, like it and introduce you as a genius for solving the problem of traffic in communities! Moreover, consider a good gift for you!