Abstract: A passive seat belt system comprising a two-point belt that in passenger restraining position extends diagonally over the upper torso of the seat occupant from a floor attachment to a retractor mechanism anchored in the vehicle roof. A carriage or trolley movable along a track that in part parallels the vehicle body roof rail and in part the windshield pillar has a belt engageable "D" ring that engages the belt intermediate the ends of the latter. This carriage is movable along the track by a nonelectrical energizer that is energized by door opening movement. Upon movement of the carriage from the retractor end of the track along the roof rail and then downwardly along the windshield pillar, the carriage automatically draws the belt forwardly from its passenger restraining position to provide unobstructed ingress or egress to the compartment through the door opening.