No one protests in a highway at night, alone, in a blind turn. When people protest on the highway, they do it in numbers large enough to stop the traffic.

Your argument is disingenuous.

I disagree that it never happens, but take it as a hypothetical test case. what then?

The devil doesn't need an advocate.

Im not playing devils advocate, I was answering a question.

>How is it possible to kill someone with your car while exercising "due care"?

It is extremely easy to kill someone with a 2 ton piece of metal traveling 70+ miles an hour.

Surely, even if you don't believe a protestors has ever been on a low visibility road, you can understand that they could be. There are limitations to how fast cars can react to pedestrians being where they aren't supposed to be.