Most of the time traffic accidents are fairly standard—the typical fender bender where one person runs into another. The officer on duty responds, assesses the situation, and completes the proper paperwork. But sometimes officers deal with much more serious, complex situations. Dealing with a hundred car pile-up, for example, is quite challenging, since it’s like carrying out multiple investigations simultaneously. When responding to multiple car accidents, hit and runs, fatalities, and high speed chases, officers can benefit by calling in Crime Scene Officers to assist with the investigation.

Because this type of case usually involves extensive damage to property, serious injuries, and/or fatalities, lawsuits will likely result. Questions of liability, product failure, etc. will also come up. Given these facts, it’s important to work together to conduct a thorough investigation. Since the CSO’s responsibilities include documentation, evidence identification, and evidence collection, we’ll look at each of those areas.

One of the most important aspects of traffic investigation is proper documentation. By observing the scene as a whole, you’ll understand it, determine what actions need to be taken, and identify the areas to search for evidence.

Photograph the scene completely. Include overview, mid-range, and close-up shots. With digital photography, you can shoot all day; there’s no excuse for not taking enough photos. Video may also be useful. Occasionally, aerial photography may be needed.

I had a case where a guy hit a girl on a bicycle. The girl broke the windshield, hit the roof, broke the back wiper blade, and then landed in the middle of the road. The driver continued on—with the bicycle attached to the front of the vehicle—for another 1.9 miles. We photographed all aspects of the scene, including damage to the bumper, skid marks, and street markings. The evidence indicated that the girl was to the right of the white line when the driver hit her. In other words, the driver crossed the white line and was nearly off the road at impact. We used aerial photography to document the scene, beginning with the impact point and including all 1.9 miles the driver traveled. In court, we used all of the photos to show what happened.

Planning is key. Develop a list of contacts and services beforehand. Then when you need something unusual, like aerial photography, you don’t have to waste time in the middle of a case trying to find it.


Careful diagramming can help explain the scene. Each diagram should be clearly labeled with relevant information such as the case number, date and time of accident, location (name of street/road/highway), orientation (North), landmarks, etc. Also indicate the location of the vehicle(s); victim(s); and evidence such as skid marks, debris, broken glass, etc. Also show obstructions or other problems.

Replicating Events
Sometimes you need to replicate important elements of the event. For example, I investigated another fatality involving a girl on a bicycle. This time, however, the driver crested a hill while the sun was setting. To see if the sun was a factor, we returned to the scene and crested the hill at the same time of day, videotaping the whole process. By replicating the event, we discovered that the driver was sun blinded when he crested the hill. In other cases, road conditions, weather, lighting, etc. may also be relevant to determining fault. Following up on these issues can be crucial to your case.

Evidence Identification and Collection
As with any case you work, finding and collecting evidence are essential. Always document where you find evidence, and photograph it before removing it. The most important source of evidence is usually the vehicle involved. Once the scene is processed and documented, the vehicle can be taken to the proper facility for processing. Before it’s moved, check for alcohol, guns and other weapons, drugs, stolen property, etc.

Important evidence may also be scattered throughout the scene. Check for debris, skid marks, broken glass, gasoline, oil, blood, and items that may belong to the victim. Evidence may be on the side of the road, in adjacent ditches, etc., so pay attention to the areas surrounding the crash.

With questions about fault and product failure, specific evidence is important. For example, in the case of the sun blinded driver, we examined the bottom of his shoe and matched the pattern we found to the brake pedal, proving that he hit the brake and tried to stop. In another case I worked, a person drove into a bridge pillar at a high rate of speed. Were the brakes faulty? Was there some other kind of mechanical failure? Driver error? Again, we examined the bottom of the driver’s shoe. This time, we found the unique pattern of the accelerator transferred to the shoe, proving the driver had committed suicide. In another case, a child was killed in a car wreck. By examining the impressions left on the body, we determined that the seat belt buckle was defective. If you don’t take the time and care, you can miss this kind of crucial evidence.

Traffic investigations can be overwhelming. But no matter the situation, the key is to follow your training. Also remember that at a traffic scene, you’re part of a joint venture. You and the other officers and specialists all bring unique skills to the job; your combined efforts make for a better investigation. It’s not about trying to take the glory. Whenever you’re involved in such an investigation, keep an open mind. Don’t assume anything. Even if a case seems obvious, investigate and see where the evidence and facts lead. Then when you turn everything over to prosecutors, you’ll be confident that they’ll have everything they need to go forward and make decisions on charges.

Dick Warrington is in research and development and a crime scene consultant and training instructor for the Lynn Peavey Company.