An 18-year-old man was killed when his motorbike collided head on with a jeep in the cavalcade escorting Union minister Ram Kripal Yadav in Patna district today, police said. Six security personnel in the jeep were injured. The collision took place near Devdahan village under Dhanarua police station when the Minister of State for Rural Development was going to Patna and the man was on his way home in Bir village under the same police station.