Out of position (OOP), in crash testing and car accident medical literature, indicates a passenger position which is not the normal upright and forward-facing position.[1] For example, a common case observed in crashes is the position of an occupant when reaching for the car radio,[2] or panic braking in unbelted passengers.[3] The concept is of interest because small changes in a passenger's position can have profound effects on the actual kinematic response, especially in rear impacts, as shown both in practical testing and theoretical models.[1]
Risk of injury
Out of position occupants are at increased risk of injury. Even low speed impacts can cause disc herniation and lumbar fracture on OOP passengers.[2]Airbags can prove fatal on OOP passengers:[4][5][6]
modulating the airbag folding pattern has been proposed as a method to reduce injuries.[7] Crash testing has shown increased forces acting on the neck and torso when dummies were leaning forward and not upright; a partial correlation with the seat stiffness has been observed, with stiffer seats increasing the force loads on the upper neck.[8]