Every time I visit the Philippines, I always see on road signs that say road was a project of a mayor, or...?

The road signs are misleading. One road sign says, "The highway was a project of President Arroyo and another one by Congressman Lapus". Isn't this illegal? There's got to be a law against this. First of all, the money to build the roads were government's money. If I were a politician and had my name on road signs, I'd be too embarred. That is too obvious. Why would politicians do that? In many countries, that is illegal and you won't see that kind of hypocisy. Which law is it that applies to this?