Thanks very much for your concern. According to some of the insurance people, lawyers on free consultation, and a policeman who is my brother, the root of the issue seems to be my lane change which is of course what the responding deputy wrote the citation for as well. A technicality.

Because I changed lanes quickly and did signal, even though the citation states I didn't, I am apparently at fault for not correctly judging that the person in the adjacent lane was driving much faster than I expected, so I am the cause of the accident. The person was definitely speeding but I only had time to look for a 1 second and the car looked plenty far away and I was moving at about 35 MPH. I figured once I was clear of avoiding the rear end collision where I would hit the person in front of me that there was time to accelerate to match the speed of the person approaching me in the adjacent lane and there would never be a collision. Clearly, they were at an excessive speed and hit the brakes to slow down a lot but she ended up rear ending me.

So the fault system seems to work as if I never changed lanes, it would've never happened. What would've happened is that I would've rear ended the person in front of me. But because that didn't happen, it is irrelevant. They strike out any causes for behavior and just go with the end results.