An adjustable airbag system for a vehicle includes an inflatable airbag and at least one tether formed from a shape memory material. The at least one tether has at least one portion thereof secured to the airbag. The at least one tether is structured to contract so as to control an inflated dimension of the airbag when the at least one tether is heated to a temperature above a transformation temperature of the shape memory material and also above a superelastic temperature range of the shape memory material, prior to airbag deployment.