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A dynamic rollover test system (DRoTS) capable of simulating rollover crashes in a laboratory was designed for research use at the University of Virginia. The goal of the current study is to describe the system's capabilities and specifications as well as to explore the limitations of the system's ability to simulate rollover crashes. The test apparatus was designed to permit simulation of a single roof-to-ground interaction of a rollover crash with the potential to be modified for evaluation of pre-roof contact occupant motion. Special considerations were made to permit testing of both dummies and post-mortem human surrogates in both production vehicles and a parametric test buck. DRoTS permits vertical translation, pitch, and roll of the test vehicle while constraining longitudinal and lateral translations and yaw. The study details the ranges of test parameters capable with the DRoTS and evaluates the limitations of the system relative to rollover crash conditions.

Rollover crashes are often difficult to reconstruct in detail because of their chaotic nature. Historically, vehicle speeds in rollover crashes have been calculated using a simple slide-to-stop formula with empirically derived drag factors. Roll rates are typically calculated in an average sense over the entire rollover or a segment of it in which vehicle roll angles are known at various positions. A unified model to describe the translational and rotational vehicle dynamics throughout the rollover sequence is lacking. We propose a pseudo-cylindrical model of a rolling vehicle in which the rotational and translational dynamics are coupled to each other based on the average frictional forces developed during ground contacts. We describe the model as pseudo-cylindrical because vertical motion is ignored but the ground reaction force is not constrained to act directly underneath the center of gravity of the vehicle.

A follow-up case study on rollover testing with a single full-size sport utility vehicle (SUV) was conducted under controlled real-world conditions. The purpose of this study was to conduct a well-documented rollover event that could be utilized in evaluating various methods and techniques over the phases associated with rollover accidents. The phases documented and discussed, inherent to rollovers, are: pre-trip, trip, and rolling phases. With recent advances in technology, new devices and techniques have been designed which improve the ability to capture and document the unpredictable dynamic events surrounding vehicle rollovers. One such device is an inertial measurement unit (IMU), which utilizes GPS technology along with integrated sensors to report and record measured dynamic parameters real-time. The data obtained from a RT-4003 IMU device are presented and compared along with previous test data and methodology.

A simple two-dimensional particle model was previously developed to calculate occupant ejection trajectories in rollover crashes. Model parameters were optimized using data from a dolly rollover test of a 1998 Ford Expedition in which five unbelted anthropomorphic test devices (ATDs) were completely ejected. In the present study, the model was further validated against a dolly rollover test of a 2004 Volvo XC90 in which three unbelted ATDs were completely ejected. The findings from the experimental testing were then compared to two real world rollover crashes with occupant ejections that were captured on video. The crashes were reconstructed by analyzing the video footage and aerial images of the crash sites. In both cases, the model was able to accurately match the observed trajectories of the ejected occupants, and the optimized model parameters were similar to the values obtained from the dolly rollover testing.

A simple two-dimensional particle model was developed to predict the airborne trajectory, landing point, tumbling distance, and rest position of an occupant ejected in a rollover crash. The ejected occupant was modeled as a projectile that was launched tangentially at a given radius from the center of gravity of the vehicle. The landing and tumbling phases of the ejection were modeled assuming a constant coefficient of friction between the occupant and the ground. Model parameters were optimized based on a dolly rollover test of a 1998 Ford Expedition in which five unbelted anthropomorphic test devices (ATDs) were completely ejected. A generalized vehicle dynamics model was also created assuming a constant translational deceleration and a prescribed roll rate function. Predictions using the generalized model were validated against the results of the full-scale rollover test to estimate the expected error when using the model in a real world situation.