I was approaching an intersection at a light that had turned red. I slowed down to stop but accidentally bumped into the car in front, 2 mph (approximately), no damage, not even a scratch. I put the vehicle in reverse and gently tapped the accelerator but it instantly raced backwards at full as though the accelerator pedal had been depressed to the floor. I tried to brake but it would not stop and smashed into the vehicle behind. It was scary and traumatizing. Sudden acceleration in reverse. I hope there are diagnostics that will corroborate what happened because I am certain to the highest degree that this vehicle is defective.