Cologne (dpa / lnw) - In a rear-end collision on Autobahn 4 in the south of Cologne on Monday, a man was trapped in his van and suffered life-threatening injuries. The 57-year-old drove shortly before noon in one of the two turning lanes of the A4 towards the A555, the police said. There he drove onto a semi-trailer truck. Rescue workers freed the driver from the wreckage and took him to the hospital. The 55-year-old truck driver suffered a shock, police said. Since the two people involved in the accident have not yet been heard, the Cologne police are looking for witnesses.