I don't have any idea, why both cars crashed. Both cars use different lanes and run straight to the road until the crash. The crash occurs just in the time, the passenger car reaches the rear axle of the truck, so that no reason is to see, why both cars are accelerated so hard. What part of the truck can be hit by a passenger car, driving parallel to the truck, just at the rear axle and not in the front of the truck?
Can it furthermore be, that the passenger car passes two times the sceene (one time short before the accident), which would explain, how they cut the car into the scene?
As I can not get any physical explanation of this accident, one possible explanation would be a good made fake, whereas the movement of the pedestrian would have been intentionally added or recorded in another time.