The driver of a semitrailer had a lucky escape when the truck she was driving careened into another truck before jackknifing and coming to rest southbound on Mt Ousley Rd.The driver, aged in her 40s according to ambulance officers, was travelling south along Mt Ousley Rd when she lost brakes and crashed into a tipper truck.The force of the collision sent the women's truck past the tipper truck, where it jackknifed around 500m south of the Mount Pleasant overpass.Emergency services arrived to find the woman out of her truck and the male driver confined inside the cabin of his tipper truck.The woman and the 45-year-old male driver of the tipper truck were taken to Wollongong Hospital, where they were both in a stable condition according to the ambulance service.The male driver was treated for chest and back injuries, while the woman suffered an injured arm.The accident caused gridlock for southbound traffic on Mt Ousley Rd, which was closed for more than six hours.Police diverted vehicles to Picton Rd and Mt Keira Rd, with cars queued back to the F6 at Appin Rd, more than 14km north of the accident.Emergency services used a crane to move the tipper truck and clear the way. Traffic northbound was also affected, with police closing a lane while efforts were made to clear the scene and rescue the drivers.Hazmat teams from Shellharbour cleaned up hydraulic fluid leaking on the road.Shellharbour Hazmat station commander Garry Lawler said he was on scene for the accident."The [female] driver of the truck was was an extremely lucky person to be alive," he said.