Boy critical after 'horror' Sydney crash A young boy is in a critical condition after a crash involving a cement truck in Sydney's southwest. A SIX-YEAR-OLD boy is in a critical condition after being thrown from a van in a "horror crash" involving a cement truck in Sydney's southwest. Police said the Toyota Tarago was stopped in a breakdown lane on the Hume Highway just before noon (AEDT) on Thursday when the cement truck crashed into its rear. The boy, who was sitting in a rear booster seat, was thrown some 10 metres from the van by the force of the crash and suffered head, chest and pelvic injuries and leg fractures, CareFlight said. The green van was left a mangled and crushed wreck. Describing it as a horror crash, CareFlight said one of its trauma doctors performed emergency roadside surgery on the boy. The six-year-old was then placed in an induced coma before being flown by helicopter to Westmead Children's Hospital in a critical condition. His 13-year-old sister, who was sitting in the front passenger seat of the van, sustained minor injuries including cuts and abrasions and was also taken to Westmead. Their mother, standing outside the van at the time of the crash, suffered suspected pelvic injuries and was taken to Westmead Hospital for treatment, police said. The driver of the cement truck and his passenger were trapped in their vehicle before being freed by emergency services and taken to hospital. The truck driver, believed to be in his 30s, is undergoing mandatory blood and urine tests. Southbound lanes of the motorway have been re-opened.