I need to know if I should sue the county for negligence.

I was in an accident this morning with a vehicle that had a flat tire and decided to just park in the lane instead of moving off to the side of the road. When the cop arrived he asked if we had seen him, we responded no because the car did not have lights on and it was 6 am. The cop then said, and this is verbatim, " How could you miss him, he's been out here two hours. I have already been out here once." Now if the cop left the scene knowing there was a car in traffic and he did not stay with his lights on to notify others, is he at fault for the wreck, or at least liable for damages since if he had done his job and been there this would not have happened.