Collision types refer to the different ways in which objects can interact during a collision. The main types include elastic collisions, where both momentum and kinetic energy are conserved, and inelastic collisions, where momentum is conserved but kinetic energy is not. In perfectly inelastic collisions, the colliding objects stick together after the impact. Another classification is based on the nature of the objects involved, such as head-on collisions, which occur when two objects collide directly, and oblique collisions, where they strike at an angle. Understanding these types helps in analyzing the outcomes of collisions in various fields, including physics and automotive safety.