Abstract
The proliferation of video recording technology has led to an increased prevalence of visual evidence in judicial proceedings concerning road traffic accidents. Litigants and forensic experts utilize this footage to reconstruct scenes and address legal inquiries. Although these recordings enable viewers to comprehend the sequence of the accident, the technical process involved in capturing a three-dimensional (3D) environment and converting it into two-dimensional (2D) electronic data inherently results in data alteration or loss. Conversely, rapid advancements in Unmanned Aerial Vehicle (UAV) technology have reduced the technical and financial barriers associated with aerial photography. Employing UAVs to acquire aerial perspectives of accident scenes facilitates the verification of the relative positions among objects and supplements the limitations posed by insufficient dynamic trajectory data. Reconstruction specialists are able to establish a simulation experiment protocol by integrating adjustment principles and permissible error margins, utilizing transverse and longitudinal measurements derived from the scene diagram, vehicle damage assessments, roadway trace evidence, dashcam or surveillance footage, as well as the final resting position and injury patterns of the pedestrian. This approach guarantees the creation of a comprehensive record for future reference. This study presents a forensic case from April 2023, wherein Pedestrian A, walking with a cane along the side of an east-west road, fell near a residential community. During the incident, three vehicles—Electric Vehicle A, Sedan B, and Sedan C—passed by and were identified as suspects. Pedestrian A succumbed following the fall. Post-mortem examination revealed contusions on the head, face, and scalp from the right parietal region to the pre-auricular area; however, no fractures or severe injuries were observed on the neck, trunk, or limbs. Scene investigation revealed no obvious damage to the vehicles, road trace evidence, or eyewitness testimonies. Surveillance footage from a parking lot across the street captured the movements of the pedestrian and the three passing vehicles. Nonetheless, the reconstruction team determined that the current camera angle and focal length differed from those at the time of the incident, likely due to post-incident shifts. Unable to physically restore the camera to its original configuration, the team employed a UAV to obtain aerial footage of the scene, which enabled the simulation of the movement trajectories of Pedestrian A and the vehicles. This approach effectively compensated for the absence of dynamic information. The forensic report was subsequently accepted by the court, and the case was concluded. This case report serves as a reference for professionals involved in accident reconstruction.
Key words: Fixed surveillance footage, UAV aerial photography, Scene reconstruction, Road traffic accident