How long does it take for an auto insurance company to investigate and claim liability?

My daughter was in a car accident on Feb. 25. She was traveling straight in the southbound lane, when a rushing man in the northbound lane turned left in front of her. The driver admitted that he was upset because he had been following a school bus for the last 20 minutes and his friend, whom he was trying to pick up, was late for work. He stated that when he saw the driveway that he cut from behind the bus to turn in then realized from the skidding that he turned in front of a car. His insurance company is still investigating and waiting for pics of the scene and his friends statement. I was told by his insurance company (USAA) that witnesses not listed on the police report could not be used, but his friend is not on the police report and they are waiting for her statement. NC State Highway Patrol responded to the scene and the driver was cited for failure to yield the right of way. The driver was apologetic and admitted several times around a number of people that he must have blanked out or was daydreaming from the frustration of the school bus. USAA is saying that they need to make sure that my daughter was not 1% at fault, meaning speeding perhaps. The officer estimated her speed at impact at around 40 mph and the speed limit is 55mph. She hit the drivers back tire of his Jeep Wrangler (small truck) causing him to rest in a small trench or ditch ion the side of the attempted driveway. The front penger side above the front tire and the front by the headlight is damaged on her car. She tried to avoid him, protect her younger sister (13) and avoid veering to much left in fear of hitting the school bus. My girls were terrified when I arrived 15 minutes after the accident. USAA stated that she may have had time to instanly stop, but she tried everything that she could do. In my opinion, she should have never been put into that situation. USAA is saying that points of contact are off, but my insurance agent said that she hit the back tire because a Jeep Wrangler is only 5 ft long and he was not towing a boat or driving a common sized vehicle. Plus the driver admitted to pushing down on the accelerator when he realized what was happening. I just need to have someones advice on this matter before hiring a lawyer. Thank you.