The THOR ATD is being developed as part of the NHTSA's advanced dummy development program. This test device is considered to have improved biofidelity when compared to the Hybrid III and is being considered for future inclusion in federal regulations. In this study we conducted five barrier crash tests in order to assess THOR's performance relative to the Hybrid III. Full THOR, Hybrid III with THOR-Lx, and standard Hybrid III ATD configurations were used in flat rigid barrier and offset deformable barrier test modes. Comparison of data from these tests shows similar values for head injury and chest acceleration, but the data traces for these injury values have different characteristics. The differences in the injury curves are the result of kinematic response differences attributable to the anthropometry and spinal compliance of the ATD's. This shows that using an ATD with a more biofidelic response than the Hybrid III may alter the kinematic response of the simulated occupant and its interaction with the occupant restraint system. Further, it is shown that addition of the THOR-Lx lower extremity to the Hybrid III does not substantially affect the head and torso response.