Most anthropomorphic test devices possess both an upper neck and a lower neck load cell to measure the risk of neck injury in crash simulations. For post‐mortem human subject (PMHS) testing, the neck is frequently assumed to be a “massless link”. It is unknown how much error is generated by this assumption. The objective of this study is to investigate lower neck loads using inverse dynamics techniques in frontal impacts. A mini‐sled was designed to dynamically test a PMHS head‐neck complex. A custom‐sized elliptical ring was used for attaching upper thoracic structures in an anatomic configuration, to account for the contribution of these structures to the overall kinematics. A six‐axis load cell was attached at the T3 level of the spine to measure the reaction loads at the upper thoracic spine. The PMHS head, C3, and C6 kinematics were measured to calculate lower neck loads using inverse dynamics techniques (IDT). A total of five PMHS tests were conducted to simulate a frontal impact. Lower neck loads were calculated using IDT, while considering either a massless link assumption (IDT‐MLA) or the actual mass moment of inertia (MMI) and center of gravity (CG) of the neck, along with measured cervical kinematics (IDT‐MMICG). The IDT‐MMICG method resulted in less error from the measured forces and moments than the IDT‐MLA method. It is recommended that instrumentation of at least one cervical level between C3 and C6 along with head/neck mass properties should be used for improved estimation of lower neck loads.