"Safety First Pays" ....then what?

There is a truck that often sits by the construction happening on Amherst Alley. It's red, and on the hatch, printed in bright yellow cursive, it says "Safety First Pays."

Everytime I see it, it takes me a while to understand. What happens after safety pays? Does it cost you?

Everytime, I shake my head. Of course not. What they really mean is "'Safety First' pays." I suppose it's not quite on par with "The panda eats, shoots, and leaves," but I think it comes close.