MAIDUGURI, Nigeria — Authorities in Nigeria said Monday that a bus has crashed into a car in northern Nigeria, killing more than 20 people.A witness told The Associated Press the vehicles burst into flame during the collision and that villagers tried to stop the fire by using buckets of water drawn from a well.At least 10 people were injured in the head-on collision in Yobe state, which borders Niger.Fatal traffic crashes are common in Nigeria, where old roads are rarely maintained and drivers often ignore speed limits and safety regulations.