I can speak on TN and GA law, since I not only investigated many accidents, am POST certified to investigate and wrote 100's of tickets because of accidents.
While the parked vechile may be ticketed for iilegally parked, or because of blocking the highway, the person at fault for the accident would be the moving vechile, since my law, they are required to not be moving at a speed faster than they can stop before hitting something in the road way. So yes, if your reflexes are so poor that you can not drive the speed limit and stop, then you perhaps should not be driving or drive slower. If you can not go the min speed on a highway and have the reflexes to stop, then you should not be on the highway.