Even if the police have already taken pictures, you also need to take pictures of the crash site and the vehicles involved in the accident. A 35 mm camera is best, but even a cell phone camera or disposable camera will do, if that is all you have available. It’s always better to err on the side of too many photos than too few when photographing an accident scene. A safe guideline would be to take 3 times as many photos as you think are necessary.
Take photographs as soon as possible after the accident because tire imprints and skid marks only last 24 to 48 hours after an accident. A tire imprint, called an “impending skid mark” is the impression left on the road when the car brakes before it actually starts skidding. By examining the impending skid and skid marks, an expert can accurately determine the speed of the car before braking. If possible, lay a yardstick or ruler next to the marks, and it will help an analyst to calculate distances when viewing the photograph.
Another photography technique that helps analysts judge distances is called the parallax approach, which creates several angles of the same object. To use this approach you plant your feet in a fixed position, and then lean as far to the left as possible and shoot the picture. Next, lean as far right as possible without moving your feet and shoot the picture. The two angles provide a perspective that can be used to judge distances.[:]