Underride accidents occur when a car goes partially or fully underneath a truck or trailer in a collision. When the car goes fully under the truck, the risk of death is high. This type of car and truck accident typically happens when the car rear-ends the trailer of the truck or collides into the side of the trailer. Although trucks with trailers are required to have rear underride guards, the guards can fail when they have a weak design, are defective, or are weak from corrosion. Because there is no.