The most common accident scenario involves the truck in either a roll-over or a frontal collision sequence. In this case, as well as in other accidents in which the cab is struck by an exterior object or hits the ground, the cab's primary task is to transfer energy backwards through the cabin in order to maintain sufficient survival space inside the cab for the occupants.
To manage this, the cab frame is made of high-strength steel, and is reinforced at the doors and the front. The cab mountings are also designed to give to a certain extent. This enables the cab to be pushed backward so as to minimise penetration and deformation likely to injure the driver.