What is the procedure under PA personal injury law regarding the determination of fault of auto accident

Accident at an intersection.: Let Street A be the street I was traveling on before I make the turn.
Let Street B be the street I was about to turn into.

I was trying to make a left at an intersection from Street A to Street B. My car was half way pass the pedestrian crossing when the traffic light starts to turn yellow. My car is considered to be inside the intersection, and so I have to clear the intersection. As I pull up to the position for the left turn, I stopped my car and watch for any vehicle approaching from the opposite direction. I saw no vehicles approaching from the opposite direction; therefore, I proceed with the left turn. As I was proceeding with the left turn, I was looking at Street B. I was about to exit the intersection and proceed onto Street B, I saw a vehicle approaching toward my car from Street A. The vehicle was driving at a very fast speed; I was very surprised as I did not see any approaching vehicle the moment before I make the turn. The Vehicle traveled on 36th Street, passed the light (the light have to be yellow at that time if not red) and hit my car from the side. The collision is the right corner of his front bumper to the side of my right wheel. I stayed at the site of the accident until the tow truck came and towed my car. At that time, the police and the other party of the accident have already left the site of accident. As I watch the tow truck drive away, an operator of a newspaper stand at the corner of the intersection approached me. He told me 2 other people saw the accident and told him that the other party of the accident ran the red light and hit my car. However, the witnesses did not stay or leave any contract information.

I did a little research on online and found if I can prove that he was speeding or running a red light, then he is at fault. From my perspective, he was definitely speeding (maybe 40 mph) and that he ran a solid yellow light (possibly a red light since the light was already turning yellow when my car was at the zebra crossing). However, I have no contracts of any witnesses. Also I am worried that the other party might make the argument of how can I not see him coming. Truth is, when I looked at the opposite direction before I make the turn, I looked approximately 2 parking spaces passed the pedestrian crossing of the lane of the opposing traffic. The time it took me to make the turn, the opposing vehicle appeared within my sight. Judging from his speed, I think his car was not within my intended line of sight; therefore, I did not see him until he was within my proximity.

From what I’ve wrote here, who is at fault. Please advise.

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