This interim report documents the progress made in the development of Vehicle Structural Identification Program (VSIP) for determining the non-linear automobile structural characteristics from barrier crash test data. Efforts have been directed toward improving an existing system identification method initiated in 1988 by Hollowell of NHTSA. The improvements made thus far include:​

• a provision for predefining certain load paths in a 1-D lumped-mass-spring (LMS) model
• relaxing the requirements of non-negative stiffness parameters in the approximation process.

Good correlations between the extracted results with the actual data either from analytical models or simplified crash test data demonstrate the feasibility of this vehicle structural characterization technique currently under development. Theoretically, the system identification approach has the potential of developing vehicle structural models totally based on accelerometer data from barrier crash tests. The method, when developed and validated, will offer an opportunity in reducing static crusher testings of components traditionally required in LMS model simulations. This opportunity will become evident as the development of the methodology continues. Further applications of this system identification approach to a full scale vehicle system using crash test data need to be explored for identifying feasibilities and issues of the technique.