sentences:  Unable to make the turn, it hit the low barrier wall, which caused the back end of the bus to swing around to the right, pointing it due northbound.The momentum of this swing caused the entire right side of the bus to crash into and then over the low wall and through the guard rail on top of it.Flipping over 270° (¾-rotation), it dropped to the freeway below, landing on its left side and hitting a pickup truck.