Once the types of collisions have been described, it is advisable to analyze what happens at the time of impact. In principle, a vehicle collision can be separated into two stages, for the simplest case of a vehicle colliding with a rigid barrier. The collision starts with an initial contact and then comes the final contact with only translation theoretically in the case of a central impact and with translation with rotation for an eccentric impact, because, in the latter case, the left corner is suddenly braked by the obstacle, but the rest of the vehicle continues to move forward, resulting in a typical rotation in this kind of collisions.