The newest “smart bag” airbag design, required in all vehicles since 2008, may not provide optimal protection for drivers wearing seatbelts, according to a study performed by the Insurance Institute for Highway Safety. Drivers wearing seatbelts—an estimated 80 percent of drivers, according to federal figures—have a 21 percent increased risk of death in cars equipped with the latest airbag models versus cars with the earlier model. The current airbag systems are more complex, go through a series of assessments before deployment, and provide restraint force that may not be sufficient or may not work as well with updated car designs.