At least one person is dead after a head on collision involving a big rig occurred on Highway 156 this afternoon. The accident took place between San Juan Bautista and Hollister near Bixy Road, when a big rig and a truck collided into one another, causing 15 to 20 gallons of diesel fuel to be spilled onto the roadway. One person was pronounced dead at the scene and a 2nd person was airlifted to an area hospital. Traffic from highway 156 was diverted onto Bixby Road while CHP cleared the roadway.