I do not understand why that study you linked is a “garbage study”?
The study posted is a typical epidemiological study. In order to address a problem—in this case, of high pedestrian deaths—the problem must first be understood.
I completely do not understand the hostility towards the CDC. All I can guess is that the CDC is not a quasi-military force like you see in movies, and people are upset that they see no Hollywood-style action from the CDC. The CDC is basically a bunch of lab-coated geeks, not exciting people at all, doing jobs whose descriptions bore most people to tears.