If the seatbelt is not worn correctly, can it affect the consequences of an accident?

The seatbelt is one of the most important passive safety elements in vehicles; since its invention it has saved millions of lives. However, it is essential that the seatbelt is positioned correctly to avoid suffering serious injuries. The chest strap must pass over the collarbone, halfway between the shoulder and the neck, and must descend across the centre of the chest. The lap strap must be placed over the hip bones, always below the abdomen. Once the seatbelt is properly fastened, pull the strap slightly upward so that it fits snugly against the body. Improper use of the seatbelt, or placing towels, cushions, covers, etc. on the seat, can cause the submarine effect, which is when the seatbelt is unable to restrain us in an accident and we slide under the lap strap.