A Large-Scale Characterization of PyCrash Collision Model Behavior Using Real-World Collision Data

PyCrash is an open-source collision simulation software package that includes a formulation of the Carpenter–Welcher collision model. Upon its release, PyCrash was accompanied by a companion paper that described its functions and provided preliminary validation results against staged collisions. However, the collisions investigated in the original report were limited to a single type of alignment. The purpose of this study was to characterize PyCrash collision model behavior against EDR data collected from a heterogeneous cohort of real-world two-vehicle collisions. PyCrash simulations were informed by the published vehicle geometries, crush profiles, and available pre-impact EDR data; simulation outputs were compared to EDR data, which served as the surrogate for “ground truth” with respect to the collision mechanics. Simulation settings were tuned to the specifics of each crash, based on previous published work and engineering judgement. Using optimized inputs for each crash, PyCrash simulations produced collision findings that were, on average, within 1 mph of the recorded EDR data. Average disagreement, normalized to EDR data, was 10% or less. The use of a large cohort of published real-world crash data indicates that PyCrash simulations can be tuned to model collision mechanics within the known error rate of EDR data for a range of crash alignments.