Another factor has been the industry's reluctance to install additional features, namely air bags, into newer car models. The manufacturers have rejected air bags in order to reduce costs, but the resulting savings are minimal compared to the personal and economic costs of the injuries and deaths caused by inadequate restraint systems. Litigation against car manufacturers usually is based on the inadequacies of the restraint systems including three-point door-mounted automatic belts, shoulder-only belts, defective buckles, lap-only belts, and tension relieving devices. The civil litigation system provides the only assurance that the automobile industry will take the "buckle up for safety" campaign as seriously as do most consumers. 44 notes