Backing up or entering a lane of traffic is always determined to be the cause of an accident. Drivers in those situations are required to yield to approaching traffic.
Answering "Pulling out of a parking lot onto a street and you have to back up to avoid on coming car and the car behind you hits you who is at fault?"
A lot of people will go to a school or church parking lot to practice. Also you can find a quiet road with one or two cars parked at the curb, practice parallel parking behind just one vehicle, then when you're comfortable with how you park behind one vehicle, find two cars to park between.
The person who ran into you from behind of course because they should be stopping, or slowing down when you turn in the parking lot.
I always turn on my hazard flashers to let the person behind know I am coming to a complete stop.
While there is no right way to parallel park, there are several unwritten rules to parallel parking that everyone should know. Rule#1 Never upset another parallel parker, especially if they park in front or behind you. Some things that upset other drivers are (a) not leaving them enough space to manuever out of a parking space (b) parking your vehicle with your front bumper mashed into their rear bumper. Rule#2 To keep your bumpers safe when parking, never park in a tight space and always give other cars enough space to exit a parking spot. A driver that's locked into a parking spot is like a caged animal...they will bump your car as many times as needed.
Good driving habits, using mirrors, parallel parking, 3 point turn, parking even in a parking space, using seat belts, signaling turns, lane changes, not speeding, etc. They just tell you where to go and watch how you do it.
Were you backing up? Would need more specific details regarding the facts of loss to be of more assistance.
Depends on the jurisdiction, but typically, two vehicles backing up is a 50/50.
behind the headlight
The person backing out. If you were in the lane/road behind them they needed to use caution when backing out.
If "Car A" is parallel parking, it has the right of way over "Car B". If the parallel park was indicated properly by "CAR A", then "Car B" should not have been in a position to pull into space behind "CAR A" as "CAR B" should have hung back as soon as the paralell park was indicated by "CAR A".
behind the headlight