Why isn't anyone talking about this: dull looking and bright orange brake lights?

Yup, they are indeed yellow. If I’m not misinterpreting what @EpicEvan777 was saying, the in-game colors look “correct” per his HDR TV:

I’m guessing that his screenshots are showing yellow taillights because it was meant to be viewed on his HDR TV. I think that’s what he was implying by the following comment:

I’m not really sure, but that’s my interpretation of it. Anyway, this thread should probably be merged with that other one to keep things tidy.