When a traffic accident occurs, it’s up to investigators to try and piece together what happened. This usually involves a number of steps, including interviewing the people involved in the accident, and consulting any video footage that happened to be taken by surveillance cameras in the area. However, it’s rare that accidents are fully caught on video, and eyewitnesses are usually unreliable.
That leaves investigators with one reliable method to determine exactly what happened (and who’s at fault): forensic mapping.
The Basics of Accident Scene Mapping
Forensic mapping can be described as both an art and a science, since it relies on the objective collection of information and the process of creating a representation of the scene. The idea is to create a landscape to represent exactly what the scene looked like upon arrival, including features that suggest what happened leading up to the accident, such as:
- Scuff and skid marks. Oftentimes, drivers brake in response to a potential accident—even if it’s already too late. Understanding when and where the skid and scuff marks stretch can help investigators understand vehicle direction, pre- and post-impact driver actions and if timely braking action was applied.
- Damage points. The type, location and depth of damage, on vehicles and on pieces of property, can help forensic experts determine what came in contact with the objects, when, and at what force (to determine the speed each vehicle was going).
- Vehicle angles. There are a handful of main types of accident scenarios, based on the angles of the vehicles involved, including head-on, right-angle, rollover, and rear-end. Each type requires a different approach to accident reconstruction, and in combination with information from points of damage and scuff and skid marks, can help forensic mapping experts understand exactly what happened.
What You Didn’t Know About the Current Face of Accident Scene Mapping
Even if you’ve heard of forensic mapping in the past, you probably didn’t know just how advanced it has become:
1. Drone-based modeling is being increasingly used.
First, the burden of photography and accident scene reconstruction no longer rests squarely on investigators’ shoulders. They now employ the use of drones, which can take images of the surroundings, and take advantage of software like PhotoModeler to completely reconstruct a 3D representation of the area. This is advantageous because it allows investigators to view the scene of the accident from new angles, and without the need to infiltrate the scene on foot; plus, investigators can virtually “return” to the scene at any time to double check their suspicions or confirm new information.
2. Measurements are taken instantly, with tremendous precision.
Reconstructing the scene of the accident visually is a major step in understanding the root causes of an accident, but investigators also need to have a precise measure for the scale of the landscape. Historically, investigators have used “walking wheels,” which allow them to measure distances on the ground by rolling a wheel on the ground and walking from one point to the next. Now, they often rely on laser-based distance measuring tools, which use concentrated beams of photons to accurately determine distance.
3. Laser scanning provides a 3D snapshot of the crime scene.
Forensic investigators are also using laser scanning to create 3D models of the accident or crime environment. A laser scanner emits a laser beam to hit a surface and reflect back to the scanner. The angle encoder information along with the time of flight of the beam are used to map that point precisely in 3d space. A scan of thousands or more points recreate a digital model of the scene. However, this method can’t provide a detailed photographic landscape the way drone photography can.
Forensic accident reconstruction has come a long way since its roots, many decades ago. However, we still have a long way to go. These three innovative technologies are making it easier for investigators to reconstruct the scene of a vehicle incident, and do so more accurately, but there’s still plenty of room to grow. The more details we can gather about the present state of the scene of an accident, the more we can learn about the events leading up to it, and the better we can serve justice to those who deserve it.