Car Accident: Rear End Collision, Who is Liable?

This is very similar to the accident that I got in 1 few years ago. Almost always, the person that rear-ends the other driver is at fault no matter what the circumstances leading up to that may be. I had to stop suddenly when a truck slammed on it's brakes in front of me and was rear-ended and the girl that hit me was cited for reckless driving for not leaving enough space between us to stop when I stopped.