I would think that following distance would be a result of Traffic Aware Cruise Control, but the 40% drop in airbag deployments cited by the NHTSA was due to the installation of Autosteer. My understanding is that TACC came before Autosteer.
I would think it would be a combination of the two. If it is just due to autosteer, what is it doing better than a human to reduce frontal impacts? This seems to suggest that the humans wreck more often when making lane changes or making evasive maneuvers.