A position securing system for restraining an occupant in a vehicle includes a harness placed about an occupant's body and including a two-part lap belt defining two lap belt straps, two leg loops, a rear belt, two shoulder belts, a back belt, and a belly-side center buckle. Anchored to the vehicle and interacting with the lap belt straps are a plurality of retractors connectable to the vehicle and interacting with the shoulder belts and the belt straps of the lap belt in one-to-one correspondence, wherein at least the retractors interacting with the lap belt straps are each constructed to include a winding drum for winding in a reel-in direction a traction member which is integrated in the lap belt strap, with the winding drum loaded by a spring in the reel-in direction. Rotation of the winding drum at least in a pay-out direction of the traction member is automatically blocked by a locking mechanism, when the occupant assumes the seated position. The blocked position of the winding drum can be released via a hand-operated control mechanism so that the occupant is able to move between seated and standing positions. A pay-out lock is operatively connected to the winding drum and constructed to act upon the winding drum in response to a sensed acceleration of the occupant, wherein the winding drum so interacts with the control mechanism and the pay-out lock as to be either securable in place by the control mechanism or acted upon by the pay-out lock, when the occupant assumes the standing position.