Photogrammetry I We make measurements from photographs using overlay techniques which can be strikingly accurate at a glance. (Please be patient, depending on your system, this may take several seconds. You will need the latest version of Windows Media Player click here for a free download.) In the above example, our use of a 3D computer scale model of an accident truck "bends" to match the accident photo, thus proving that the dashboard moved back to hit the seatbelted driver.

	Photogrammetry II Analog techniques of determining measurements of skidmarks and other objects from accident scene photographs. Analog techniques involve overlapping measurement grids included in a comparison photograph taken from the same viewpoint as the accident photo. The result is usually more accurate than purely mathematical approaches, and is easily understood by any viewer. The following is an example of using overlapping photos to accurately reconstruct an accident scene. The berm, the PG&E Plant, road edge, etc. are exactly positioned in each photo. This allowed the jury to access the accuracy of the reconstruction.
		Lights of PG&E Plant Right wheel mark in dirt Gouge on berm right wheel path		PG&E Plant Left wheel path (relative to right) Gouge location Reconstruction of right wheel path
	CHP PHOTO		RECONSTRUCTION OF ACCIDENT SCENE
	TRANSITION	The CHP photo disolving into the overlap of the reconstructed gouge and skidmark.

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