vehicle accident

Last Thursday morning at 650 am. My wife rear ended a truck. It was dark, foggy, and raining.She was she was on her way to school, Speed limit is 45, she was driving at under 40,the trucked was stopped to make a left turn,his tail lights were tinted so dark, you couldnt see them in this condition, by the time she drove up it was to late to stop. She hit his vehicle. She turned sharp right to avoid a serious accident. it damaged his right side fender and bumper.her car the whold front was severe. The man got out of his truck to check his damages and the got back in to move his truck and then called for medical assitance for him self. He never ask my wife if she needed help. a pass byer stopped to assist her. We know if you rear end somebody, your quilty. But his tail lights were so dark his vehicle was like invisible .How can somebody be quilty by hitting somebode with tail lights tinted dark,,can you give us advise