CHILDREN aged up to 12 should be made to sit in booster seats because back seats on most Australian cars are too deep to allow them to sit up properly, making them seven times more likely than teenagers to sustain spinal and abdominal injuries in a crash.Although about 60 per cent of all back seat passengers are children, researchers at the Prince of Wales Medical Research Institute tested 50 common cars and found some had seats so deep that a 14-year-old of average height could not sit comfortably without slouching.”[Slouching] causes the lap belt to slide up over their abdomen instead of sitting low across the hip bones, and the shoulder belt to lie across the neck,” the institute’s Lynne Bilston, said yesterday.”This can put all the force of a crash on the child’s soft abdomen and lower spine and allow the head to hit the car. Having the belt across the neck can cause serious neck injuries.”She is calling on car manufacturers to consider urgently reducing the depth of back seats by at least five centimetres, a change which would fit about 34 per cent more children aged eight to 15 but also allow adults to sit comfortably.An average 12-year-old, at 150 centimetres tall, had thighs longer than the base of the rear seat and were tall enough to allow the shoulder belt fitted properly in more than half of the cars measured, she said.”Car manufacturers have slow design cycles so if this change was made, it would be three or four years before we would see it introduced, but it would definitely reduce spinal and abdominal injuries and save lives.”More than 3000 children are injured in car accidents every year, and older children would accept being in booster seats if it became normal practice, Associate Professor Bilston said.”It’s all about peer pressure. It’s common practice now in Europe and if it became common here, I doubt parents would have problems getting children to comply.”The institute also wants the NSW Government to introduce new road rules, approved by the Australian Transport Council in February last year, making it compulsory for children aged up to seven to sit in booster seats.The rules have been adopted in Queensland, Victoria, South Australia, Western Australia and the ACT, and a spokeswoman for the Roads Minister, David Campbell, said they were expected to be introduced in NSW soon.