Workers install engine on the bus in a factory of Chongqing Hengtong Bus Co., Ltd., in Chongqing, southwest China, Dec. 26, 2011. (Xinhua/Li Jian)

Workers install windows on the bus in a factory of Chongqing Hengtong Bus Co., Ltd., in Chongqing, southwest China, Dec. 26, 2011. (Xinhua/Li Jian)

Workers pull the bus out of painting workshop of Chongqing Hengtong Bus Co., Ltd., in Chongqing, southwest China, Dec. 22, 2011. (Xinhua/Li Jian)

A worker paints the school bus body in painting workshop of Chongqing Hengtong Bus Co., Ltd., in Chongqing, southwest China, Dec. 22, 2011. (Xinhua/Li Jian)

Workers in a factory of Chongqing Hengtong Bus Co., Ltd., in Chongqing, southwest China, Dec. 26, 2011.

Founded in 1939, the company started the research and development of safe school buses in 2004. Its new type of school bus is equipped with ten leading safety systems to guarantee the safety of passengers.

A string of school bus accidents in recent days raised national concern over school transport safety. Chinese Premier Wen Jiabao has called on government departments to "rapidly" draft safety regulations and standards for school buses while further improving the design, production and distribution of the vehicles.