Six people were killed and two others seriously injured Thursday morning in northern Serbia when a van slammed into a tractor trailer, DPA quoted Tanjug news agency. The van, driving medical workers to a conference in Belgrade, had slammed into the trailer loaded with corn. The accident, still under investigation, occurred before dawn 100 kilometres north of Belgrade, in the farmland province Vojvodina. Particularly when agricultural work peaks in spring and autumn, Serbian roads become infested with farming machinery which moves in the dark without lights. In combination with the traditionally erratic driving style, the practice often leads to fatal accidents.