An aging population's effect on MAIS 3+ injury trends for passenger-car drivers in frontal crashes is projected and compared to the effects of projected changes in fleet composition, changes in belt usage, and changes in airbag availability. It is determined that increased frailty due to an aging population will result in 19816 to 43568 additional injuries from 1996 to 2012. Aging is shown to have an effect similar to the increased presence of light trucks in the fleet (a cumulative increase of approximately 47428 injuries). Aging and changing fleet composition are shown to have a smaller effect than the projected increases in seatbelt use or airbag availability. After 2012, however, airbag availability and seatbelt use will plateau, while societal aging will continue.