I've seen hundreds if not thousands of deer that've been hit @ Interstate speeds. I can't say I've ever seen body parts fly off while watching one get hit (I've seen 4 happen live). Even the deer that get caught under the front bumper of a semi just get ground up, body parts don't just fly off. Even buck antlers stay attached until someone comes along with a sawzall.
I'm going with helmet or backpacks.
years ago i was at the scene of a auto death. guy wandered out of a bar to take a leak off a bridge, semi hit hit got tangled up in the tire. his guts were scattered over probably 20 yards or so. but... it took off the top of his head right above the eyebrows, leaving this shinny brain cavity with nothing in it in the skull. the semi driver kept going.
