A driver killed by his own container truck after being hurled out of the cabin in a crash in Lai Chi Kok last week was not wearing a seat belt, a preliminary police investigation has found. Lau Kwai-yam, 37, was hurled out of his vehicle last Tuesday when his truck ploughed into the central divider in the New Territories-bound lane of Ching Cheung Road. The truck continued to travel forward before rolling backwards and running him over. He died in hospital. The container, loaded with textbooks, shot across the central divider, hitting four other vehicles in the opposite carriageway and injuring eight people. The accident happened as Lau was returning from the mainland. A police source said the container was not properly secured on to the back of the vehicle. Four twist locks, two on each side, are used to secure cargoes. 'Initial checks showed two twist locks on the left side of the vehicle were not in the locking position,' the source said. 'But we believe this is not the single cause of the accident. Other factors like speed and the road situation might be included.' Officers and government chemists will carry out a test at the scene in an attempt to determine whether the truck was travelling faster than the limit of 70km/h. Investigations failed to find any mechanical problems with the vehicle nor evidence it was overloaded. Container Transportation Employees General Union chairman Tse Long said some container truck drivers ignored regulations and did not wear seat belts because they found them uncomfortable and inconvenient when they got out to load and unload goods.