The Application Of Photogrammetry And Fixed-parameters Computer Simulation In Traffic Accidence Investigation And Analyzing

Objective To study applying digital photogrammetry with common digital camera and commercial software to traffic accident scene investigation, and applying fixed-parameters computer simulation to analyzing crash-course and biomechanical responses in automobile-to-pedestrian and automobile-to-bicycle accidents. Method The process of digital photogrammetry included taking photos, calibrating the digital camera, analyzing photos with photogrammetry software, and processing with computer-aided-design software. The accuracy and the precision of this method were tested in simulative traffic accident scene, and the feasibility of this method was tested in real traffic accident scenes. Automobile (bus, minibus, car and truck), bicycle and pedestrian models were constructed by multi-body dynamics computing method, then the crashes were simulated under different impact speed (20, 30, 40, 50 and 60km/h) and position (automobile-to-pedestrian: automobile's front side impacted the front, lateral and rear of pedestrians; automobile-to-bicycle: automobile's left-front, front and right-front impacted the bicycle left side). Crash-courses and their biomechanical response (head, neck, chest and legs) were studied. Result In simulative traffic accident scene the mean relative error and the standard deviation were respectively used to represent the accuracy and the precision. The results were respectively 0.58% and 0.68%. In two real traffic accident scenes, this technique was successfully applied in measuring, sketching and reconstructing scenes. Based on fixed-parameters computer simulation, following results were accessed: If the type of automobile and the impact position were the same, the crash-courses are similar (impact speed≤60km/h); There were some characteristics in head, neck and leg's injuries under different speed, automobile type and impact position; In automobile-to-pedestrian simulation under low impact speed the primary injury was head injury caused by falling; There was a linear correlation between the crus axial force and impact speed. Conclusion The accuracy and the precision of this photogrammetry method meet the demand of traffic accident scene investigations, and there are several special advantages. The fixed-parameters computer simulation can be well applied to analyzing crash-course and biomechanical responses (head, neck, chest and leg).