A safety system includes an airbag configured to deploy from a rail and restrain motion of an occupant, a tether configured to deploy from a pillar, and an anchor coupling the tether and the airbag. The anchor is configured to travel from a stowed position proximate to the rail to a deployed position spaced apart from the rail and spaced apart from the pillar in unison with deployment of the airbag. The safety system includes a tensioning mechanism configured to apply force to the tether. Motion of the anchor is controlled by the force applied by the tensioning mechanism.