The Chinese government says 18 people have died after a bus overturned in Tibet. The State Administration of Work Safety said in a notice on its Web site Monday the bus flipped over on Friday morning in Naqu district. It did not say why there was a delay in reporting the incident. The notice said 28 people were injured, 17 seriously injured. Road accidents are common in China, where often overloaded vehicles must contend with poor road conditions and bad driving habits.