A bridegroom and 15 of his wedding guests have died after his vehicle plunged off a cliff in central China.Li Zhimin was returning from his wedding with 31 friends and family when the small truck he was driving veered off a road and plummeted 80m (262 feet) down a cliff amid poor weather.Sixteen other passengers are being treated in hospital for injuries, with six in a critical condition.It is not yet known whether the bride was one of the victims.OvercrowdingMr Li and 13 others died immediately in the crash on Wednesday, while two others died in hospital on Thursday. The truck was only allowed to carry four people, but the... passenger number was eight times moreLiu XiangdongRescue supervisorAuthorities believe overcrowding and poor weather were the main causes of the accident, the rescue supervisor told China's state-controlled news agency, Xinhua."The truck was only allowed to carry four people, but the actual passenger number was eight times more," Liu Xiangdong said.China has the deadliest roads in the world, according to the World Health Organisation (WHO).Official estimates say 100,000 die on China's roads every year but the WHO says the road toll is double this figure