It is well documented that among the whole population,small female,elderly,and obese populations are often at increased risk of death and serious injury compared with mid-size young male in motor-vehicle crashes.This study explored the reasons of these increased injury risks and reviewed current and future injury assessment tools that would benefit the protection for various vulnerable populations.An overview of recent research focusing on vulnerable populations,including field data analyses,statistical human anthropometry model development,and parametric human finite element modeling,conducted at the University of Michigan Transportation Research Institute (UMTRI) was also provided.