Accuracy of Three-Dimensional Photogrammetry as Established by Controlled Field Tests

Photogrammetry is the science of obtaining spatial information from photographs given a set of key reference points. Vehicular accident reconstruction frequently requires using the photogrammetric process to obtain dimensions of such items as skid mark length, vehicle rest positions, or depth of vehicle crush. This paper briefly describes the generalized three-dimensional photogrammetric process. Findings are then presented which show the accuracy of this process when applied to simulated reconstruction situations involving skid marks and vehicle crush. Specifically, three sets of photographs of simulated skid marks and one of vehicle crush were analyzed photogrammetrically. The results were then compared to a blind set of survey data which was revealed only after the photogrammetry calculations had been completed. The comparison between the survey data and photogrammetry calculations are presented in graphical form.