Current procedures for evaluating vehicle safety designs for drivers use human surrogates with only a small number of body sizes, while field data analyses have shown significant stature and obesity effects on occupant injury risks in frontal crashes. In this study, six finite element human models, including three models corresponding to the three sizes of adult crash test dummies (small female, mid-size male, and large male) and three obese models with the same reference statures but a BMI of 40 kg/m², were developed by morphing the GHBMC M50-OS model using a landmark-based radial basis function and a regional mesh morphing approach. US NCAP frontal crashes were simulated with the human models on the driver side. For both non-obese and obese drivers, the short female and tall male had higher injury risks than the mid-stature male. At each stature, higher injury risks were observed for obese drivers than for non-obese drivers. These results suggest that driver body size and shape affect occupant interactions with the restraints, occupant kinematics, and injury risks in severe frontal crashes. Simulations with parametric human body models capable of representing the diversity of occupant populations may provide a means of improving protection for individuals who differ in size, shape and position from the surrogates typically used for restraint optimisation.