A restraint system for use in a vehicle may include a seat; a belt system having at least one belt and at least one belt-adjusting mechanism; and at least one buckle. The belt-adjusting mechanism may be disposed at a first side of the seat and the buckle may be disposed at a second side of the seat. An end portion of the belt may be connected to the belt-adjusting mechanism; and the belt system may have a locking member for locking with the buckle. The restraint system may also include a belt pretensioner that includes a force transmission member; and an actuator configured to actuate the force transmission member for tightening the force transmission member and/or the belt. The actuator may be configured to be actuated and/or triggered by an operator.