When driving on a highway, there is nothing as worrying as seeing a tractor-trailer going out of control behind or ahead of you.  Due to their gigantic sizes, auto accidents involving 18-wheelers are often very consequential in terms of damages and casualties.  Jackknife accidents are especially fatal, as they usually involve multiple vehicles and a lot of momentum force.    So, How Do Jackknife Accidents Occur? A jackknife accident is where a trailer truck folds in on itself such that the cab bends at a sharp angle with the trailer, in an apparent "V" shape. The scenario derives its name from the hinging effect of a pocketknife folding into its handle while being closed. Jackknifes occur when a truck makes a sudden stop or swerves suddenly to avoid hitting something on the road. [...]