The structures in the tracheobronchial tree are well protected, so it normally takes a large amount of force to injure them.[6] In blunt trauma, TBI is usually the result of violent compression of the chest.[5][14] Rapid hyperextension of the neck, usually resulting from vehicle crashes, can also injure the trachea, and trauma to the neck can crush the trachea against the vertebrae.[14] A crush injury of the larynx or cervical trachea can occur in head-on collisions when the neck is hyperextended and strikes the steering wheel or dashboard; this has been called a "dashboard injury".[14] The larynx and cervical trachea may also be injured in front-on collisions by the seat belt.[14]