Vehicle Shape Influence on Virtual Forward Simulation of Car Crashes

The progressive deployment of active safety systems requires precise tools to assess collision mitigation performance. Virtual Forward Simulation (VFS) plays a pivotal role in the prospective assessment of Advanced Driver Assistance Systems (ADAS). Reliable VFS routines depend on validated models capable of simulating driving dynamics and accurately resolving collision mechanics when ADAS interventions fail to prevent impact. However, in accident reconstruction practice, software tools often do not include the exact geometries of the vehicles involved. As a result, when graphical data is compiled for detailed accident records, vehicle shapes are typically represented in a simplified way. This means that VFS, when used to evaluate ADAS performance, relies on simplified vehicle shapes as input. Such simplifications can have unpredictable effects on the accuracy of impact simulations. This study examines how vehicle shape influences the reliability of 2D car-to-car collision simulations A validated special-purpose VFS tool, based on a Reduced Order Dynamic Model (RODM), was used to simulate road collisions using progressively simplified vehicle geometries. The simulations were statistically analyzed and verified through a case study based on real-world accidents. The analysis highlights the drawbacks of simplified shapes for both ADAS evaluation and reconstruction accuracy. Findings indicate that while simpler collision models remain insensitive to geometric variations, vehicle shape exerts a significant influence on advanced VFS models. Therefore, when utilizing advanced methodologies like RODM, incorporating detailed and realistic vehicle geometries is essential. Neglecting this leads to a significant underestimation of key parameters, specifically Delta-V (by more than 5 km/h) and occupant injury risk (by up to 60% in real-world scenarios).