It wouldn't necessarily be a sentence it'd be a word it'd be therefore <span />
The revision that will make the sentence more precise is this: I HAVE SOME CHANGES THAT I BELIEVE WOULD MAKE THE TRAFFIC LIGHT SYSTEM WORK BETTER.
This sentence is more precise, because it gives accurate information about the intention of the speaker. The original sentence was a little bit confusing because of the word choice of the speaker but the revised version chose the right words to express the speaker's intention.
