When adjusting the head restraint in a vehicle, it should be positioned at the level of the top of the ears or the top of the head, and as close to the back of the head as possible. This helps to prevent whiplash in the event of a collision, by limiting the movement of the head and neck.
The head restraint should be adjusted so that it is at a level higher than the top of the shoulders, and it should be as close to the head as possible without causing discomfort. It is important to adjust the head restraint properly for each individual who will be sitting in the seat, as people come in different sizes and shapes, and a poorly adjusted head restraint may not provide the necessary protection in a collision.
It is also important to note that the head restraint should never be removed or adjusted in a way that takes it away from the proper position, as this could increase the risk of injury in the event of a collision.