I am driving along XX.
At the intersection of XX and YY, the light was green so I continued to go straight.
The signal light turns yellow. Unexpectedly, traffic forms and the cars ahead of me stop. Hence, I am stuck in the middle of the intersection.
Note: this intersection is a camera zone (cars that pass on a red light will be fined).
I immediately decide to change lanes to the left, because if the light turns red and I continue to stay in the middle of the intersection, (1) I will cause traffic for the cars passing on YY, and (2) my photo will be captured and I will be fined for “crossing” on a red light.
Note: the lane to my right is backed up by traffic, but the lane to my left is free for many spaces ahead of me.
By this time, the signal light turns red. Thus, I look over my left shoulder, and after verifying 100% that no car is on the lane to my left, I signal and am changing lanes when all of a sudden, a car appears in the left lane and the front left portion of my car collides with the rear right portion of his car. I follow him to the nearest parking lot, where we exchange our information.

Possibility: There was no car coming from the lane to my left when I looked over my left shoulder. But a car was in my left lane when I changed lanes. Thus, he was behind me, and upon seeing the light turn yellow, he too changed lanes.


Possibility: There was no car coming from the lane to my left when I looked over my left shoulder. But a car was in my left lane when I changed lanes. Thus, he sped through the red light, which caused our collision when I changed lanes.

Am I 100% at fault? Please help!