This paper describes the biofidelity of the TRL lower leg impactor (here after referred to as “The Impactor”). The knee-bending angle biofidelity of The Impactor is compared with the THUMS (Total HUman Model for Safety) FEM human body model. Detailed sedan and SUV FEM models were generated and were correlated with test results. FEM results show The Impactor’s knee-bending angles correlate well with test results.

When the tibia deflection of The Impactor is small, The Impactor has a larger knee-bending angle than the THUMS model in a finite element (FE) analysis of the pedestrian impacted by a sedan. When the tibia deflection of the THUMS is small, The Impactor has a similar knee-bending angle to the THUMS model in FE analysis of a pedestrian impacted by an SUV.

Movement of The Impactor coincides with the THUMS model in an FE analysis of the pedestrian impacted by a sedan until the medial collateral ligaments ruptured. Movement of The Impactor does not coincide with the THUMS model in FE analysis of a pedestrian impacted by an SUV with a bumper height 520 mm. If the bumper height of the SUV is less than 420 mm, movement of The Impactor is similar to that in the THUMS model.

Biofidelity of the knee-bending angle of The Impactor is not sufficient if compared with the THUMS model. Deflection of the tibia should be taken into account to improve biofidelity of The Impactor’s knee-bending angle.