Active bolster with double-hinged tether tabs

An active bolster for an automotive vehicle has an inflatable bladder formed by a reaction wall for mounting against a rigid structure of the vehicle and an expansion wall overlying the base wall. The base wall and expansion wall are comprised of molded plastic components. At least one of the reaction wall and the expansion wall includes a plurality of tether tabs, each tether tab having a contoured edge defining a movable flap. The contoured edge has first and second ends defining a first hinge axis and a pair of complementary undulations defining a second hinge axis substantially parallel to the first hinge axis. The movable flap has an attachment region joined to the other one of the reaction wall and the expansion wall, and the second hinge axis extends between the attachment region and the first hinge axis.