The objective of the present study was twofold. First, to evaluate the External Peripheral Instrument for Deformation Measurement (EPIDM), and arrive at a methodology to be used in impact experiments. Second, was to conduct sled tests on an unembalmed human cadaver and a 50th percentile Hybrid III manikin to determine the thoracic deformation contours and, using these contours, to evaluate injury criteria such as normalized chest compression and viscous response. Initial evaluation of the EPIDM indicated the static drift over time to be minimal when the device is allowed an initial “warm up” time of 15 to 30 mts. The EPIDM methodology used in this study was based on three steps: (1) Prior to any testing, zero all gauges on a flat surface. (2) instrument the surrogate last before conducting the sled experiment, and (3) after the test, repeat the calibration procedure to ensure a proper working of all the gauges. A three-point belt restrained human cadaver and a Hybrid III manikin surrogate underwent sled tests at 48 kph velocities. These tests indicated that the EPIDM device can follow the dynamic thoracic deformations at impact. The deformation contours also permitted the computation of the following variables: Normalized compression histories, chest compressive velocities, as well as the viscous response (product of the normalized compression and the compressive velocity) characteristics. These studies suggest the potential of the EPIDM to derive injury criteria in an attempt to assess the crashworthiness of vehicular structures.