Analyses were performed to quantify the conditions under which the knee is loaded in frontal motorvehicle crashes and to thereby provide insight on the test conditions that should be used in future studies of the tolerance of the knee to loading of its anterior surface. These analyses estimated knee angle and the orientation of the femur relative to the knee bolster during bolster loading, the area of knee over which knee bolster contact loads are distributed, and knee loading rate. The postures of the lower extremities of 18 male and 18 female occupants relative to the knee bolster in three vehicles were used with a 2D kinematic model of the lower extremities to estimate occupant knee angle and the angle between the long axis of the femur and the plane of the knee bolster at initial knee contact and after 100 mm of bolster stroke. At knee contact, the average knee angle was 92°±13° (mean ± sd) and average bolster-to-femur angle was 67°±6°. After 100 mm of bolster stroke knee angle was reduced to 75°±11° and bolster-tofemur angle was 65°±5°. Bolster-to-knee contact areas produced by a single set of cadaver knees impacting four driver knee bolsters selected for their widely varying force-deflection characteristics resulted in forces being distributed over the majority of the anterior surface of the patella. Analysis of femur force histories in FMVSS 208 and NCAP tests indicated that median femur loading rate was approximately 250 N/ms and 90% of femur loading rates were below 1 kN/ms. These values are only rough estimates of knee loading rates, since contributions of axial and shear forces transmitted through the knee to axial femur force are not quantified in FMVSS 208 and NCAP tests.