Four Ways Laser Scanning Benefits Accident Reconstruction
August 18, 2014
With 33 years in accident reconstruction under my belt, I go back, not quite to the stone-and-chisel era, but to the 100-foot steel tape, chalk and bubble line level. It began in 1982 with the Maryland State Police where I specialized in and taught accident reconstruction.
In 1993, my wife and I started TransCon Crash Scene Investigations, a private reconstruction services and collision analysis firm. In 2010, after 17 years of shooting scenes with a reflectorless total station and delivering 2D work products, we wanted to move forward in bettering our services for our clients, so we began looking into how we could do that through technology. We considered a robotic total station. But there was also this new thing coming into the forensic field called a 3D laser scanner.
So instead of taking a little step, we decided to take a large step. We looked at our options and trends and were most impressed with the Leica ScanStation C10. Now, with four years of using it in the crash scene world, I can say that the leap in technology—and the benefits the laser scanner provides—was well worth the investment.
1. Scanning Keeps Users out of Harm’s Way
One of the biggest benefits of laser scanning for accident reconstruction—and my wife really likes this part—is user safety. We’re not entering the roadway at all. We’re up on a hill or on a sidewalk and out of harm’s way. I know all too well the dangers of working around traffic. In 1986, I was run over by a tow truck while working an accident scene as a Maryland state trooper. After my medical retirement, I was encouraged to put my accident reconstruction experience with the Maryland State Police to work in the private sector. (That’s how TransCon Crash Scene Investigations came about.)
2. Scanning Accelerates Reopening of Roadways
From an incident-command scenario, the trend throughout the nation is to get traffic free-flowing as fast as possible, especially on interstate systems. The laser scanner is a tool that can take 80 percent of the typical closure time right off the chart.
Documenting a traffic incident by hand takes hours. But with a laser scanner, we can clear the scene of a fatal accident within minutes, open the roadway, and continue to scan the marked evidence while traffic is free-flowing. By not disrupting traffic, we’re providing the police an incredible service in significantly reducing the traffic backups that are created while fatal accidents are under investigation. Instead of saying, “We’ll be ready to open traffic in two hours,” they can say, “We’ll be able to open traffic in 20 minutes.”
3. Scanning Provides Comprehensive Documentation
Even though the laser scanner enables us to work faster, we are documenting even better. Without a laser scanner, it’s up to investigators to choose what we want to gather and archive and document. As a result, we’ve been challenged with, “Well, you didn’t get this,” or “Why did you choose that to measure?” With the laser scanner, interpreting what we need to measure on the scene to provide our service is eliminated because the point cloud captures everything.
This comprehensive documentation is important for our clients and for business. When we travel across the nation to perform a scan for an accident investigation, we don’t know if the case is going to morph into a big case or remain a small case. We’re not sure how the witnesses are going to testify. Back when we were using a total station, there were times when we had to go back to the scene to capture measurements from a different perspective because new witnesses came forward. With the laser scanner, no matter what happens, we now have everything we need. So the ability to grab everything at one time is a huge benefit for everyone involved.
4. Scanning Delivers Accurate, Compelling Data in Court
In the litigation world, laser scan data solves cases; it closes cases; it enlightens decision makers. Instead of an opinion from an expert that can be challenged, we provide a demonstrative piece of evidence that is what it is.
In my pre-scanner days, we first interpreted what we wanted to measure, and that interpretation was often challenged. Then we were challenged on how we measured it. And then we got challenged on how we took the measurements for our demonstrative data—whether it was the old days of graph paper or more modern methods using CAD systems. And accuracy does count. In a lot of cases, if you’re off in your calculations by more than five percent, your credibility is challenged.
In comparison, it’s very difficult to challenge our laser scan data because the point cloud in its raw nature is what it is. We just upload it, and it’s done. We don’t have any manipulation to the point cloud. When the other side sees that the scan data is not subjective, and that scan data from this same technology has been accepted as evidence in previous court cases, they just fold. So on the litigation side of this, it’s pretty black and white once the ScanStation data is developed into the strategy outline of the case.
Jurors also like the visual work products we create with scan data and point cloud processing software. With the advent of “CSI” on television, jurors are expecting the police or a forensic expert to come in and give them that “CSI effect.” The Leica ScanStation is able to produce that for them. Whether it’s in mediation/arbitration, depositions or trials in front of a jury, a picture is worth a thousand words holds true in either settlement or in criminal proceedings, right or wrong, guilty or not guilty.
For more information on 3D laser scanning for accident investigation and reconstruction, contact us.
————- About the Author: Glen Reuschling, is founder of TransCon Crash Scene Investigations, one of the nation’s leading accident reconstruction firms. He is certified by the Accreditation Commission for Traffic Accident Reconstruction (ACTAR), an internationally recognized commission with more than 1,260 accredited reconstructionists.