A high energy side impact dummy (HE-SID) was developed for special vehicle development used for law enforcement and VIP protections subjected to improvised explosive device (IED). MIL-SID, i.e. ES-2 ATD with Hybrid III head/neck and MIL-LX design, was used to develop the test rig and define inputs to mimic the IED test conditions. It was found that the MIL-SID shoulder and rib modules were not durable enough to survive the impact during the testing. In addition, the shoulder biofidelity was lacking and requires improvement. A new shoulder structure was designed to improve the shoulder biofidelity. Finite element analysis was conducted to optimize the shoulder design according to the target biofidelity as defined by a series of 12 PMHS shoulder impacts. The MILSID shoulder cam design was replaced with a single shoulder rib integrated with damping materials. A 3D deflection measurement system was developed to measure the shoulder deflections. The 3D deflection measurement system consists of a linear potentiometer and two rotary potentiometers. An algorithm was developed to calculate the deflections at its shoulder joint attachment location. Hardware was fabricated and retrofitted in a MIL-SID for verification and validation. The preliminary test shows that the thorax durability issue was addressed. The ATD was able to withstand numerous tests without any damage. The new shoulder design demonstrated good biofidelity under high energy test conditions.