Photogrammetry is often applied to the process of crash reconstruction in cases where photographs were taken, but measurements were not.
Many times the only evidence that exists after a collision has been cleaned up are photographs. These photographs can come from police, bystanders, news agencies and insurance adjusters. In many instances dimensional information can be derived from these photographs to provide greater detail for the collision reconstruction.
Clear the roads fasterRecently in an effort to reopen closed roadways more quickly on scene police investigators have used photogrammetry to speed up the process of collecting measurements. It has had very limited success for that application.
Crashteams reconstructionists have the training and computer software to take an old photograph and convert it to a top-down view, to scale. Essentially, with some reference measurements (4 known points that can be obtained after the photo is taken) the photograph can become the diagram, complete with measurements.
Often this is a procedure that becomes necessary when photographs of an accident scene have been taken by on scene investigators, but no measurements have been recorded.
Photogrammetry allows Crashteams investigators to measure the scene from the photos, many years after the fact.
How accurate is photogrammetry?This is a common question; especially when the entire reconstruction is based on the measurements of the scene gained by the process. It can be very accurate in the hands of a trained individual, with the right camera, right software, and many reference points. We hesitate to suggest a degree of accuracy.
However, we can say it is far less accurate than measuring with the total station instrument, and takes even longer. We can also say that the results can always be assessed for accuracy by a Crashteams professional.
Famous CasesPerhaps the best example is the James Dean crash of September 30 1955. Our Mike Kennedy was asked to reconstruct that crash to answer some key issues; who was driving, impact speeds etc. No proper measurements were taken by the on scene CHP officers, but they did take photographs. Mike used the picture below to rectify and transform it to a top down view.
The wheelbase of the old Ford business coupe was used to establish the mathematical relationship between the photograph and the real scene. The transformed photo was essential to the analysis, and integrated in to the scene diagram in 2D and 3D.
Photogrammetry has been a key process to solving lots of cold cases.
Scale models of the actual vehicles were simply placed on the skid marks after the photograph was rectified. This reveals the exact orientation of the vehicles at impact, and enhances the precision for the speed calculations.
Read the full story abouth James Dean's fatal accident reconstruction.
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Our ServicesOur Crashteams reconstructionists are the most highly trained and qualified individuals in the industry.
All Crashteams experts utilize survey equipment to produce precision crash scene diagrams and 3D models.
All Crashteams reconstructionists are qualified expert witnesses and have given testimony at all court levels and jurisdictions.
Your Crashteams experts can interview witnesses and secure detailed statements, as recorded interviews in audio and video formats.
Crashteams experts are all trained and certified as forensic animators. You will find it advantageous that your reconstructionist and animator are the same person.
Crashteams experts are qualified to use many different software applications to simulate the crash for the purposes of answering what if scenarios and exposing errors in the hypotheses advanced by oppsing experts.
You may send us reports from opposing experts and we will be able to tell you immediately if a rebuttal is useful and if so, we produce professional, objective, commentaries.
Crashteams have the expertise coverage and manpower to take on all the crash investigation requirements of a community as a public private partnership.