California Case Sets Important Precedent for Leica ScanStation Data as Scientific Evidence

Julia Bertoli was crossing an intersection with three high school friends in Sebastopol, Calif., on June 3, 2009, when the 15-year-old was struck by a car. The impact—which threw Bertoli approximately 30 feet in the air and 40 feet down the roadway—resulted in traumatic brain and bodily injury.

It was a bright, sunny day when the accident occurred. The teenagers were using the designated crosswalk. There were no line-of-sight obstructions. Yet the driver, who was traveling within the speed limit, said she never saw the pedestrians. After reviewing the details of the case, Bertoli’s attorney pinned the cause of the crash on significantly overgrown trees that violated city, county and state codes.

To build his $20 million case against the city and the California Department of Transportation (Caltrans), Bertoli’s attorney turned to Craig Fries, of Precision Simulations Inc. “The real fight came down to the shade of these trees—having to prove that they shaded the crosswalk and having to prove that, had these trees been cut according to code, it would have made a functional difference in the outcome of the event,” said Fries, founder and CEO of the California-based crime scene documentation, reconstruction analysis and 3D visualization firm.

Over the next six years, Bertoli’s attorney, who had no previous experience with laser scanning technology, employed not only the most prolific but also the most novel use of laser scan data that Fries has ever seen. As a result, the judicial rulings in Bertoli v. City of Sebastopol et al. set an important legal precedent in California when Fries’ Leica ScanStation data—and all the expert analyses built upon it—was admitted into scientific evidence.

Creating the 3D Working Model

Precision Simulation’s case preparation comprised nearly 1,000 hours of labor. It began with the documentation of the scene. Fries laser scanned the roadway, buildings and the trees with his Leica ScanStation C10 system. “We opted for exceptionally dense scanning in order to create a very detailed and dimensionally accurate model,” Fries said.


The surface of the road and the outline of the trees were first modeled within the Leica Cyclone point cloud processing software. Then, using the Leica CloudWorx for 3DS Max plug-in, the point cloud was imported into AutoDesk 3DS Max software for further modeling in that native environment. “3DS is the software used to create all of our computer animations,” Fries said. “Having the data in 3DS allows us to mix scan data with all the other computer-generated elements in the same piece of software. Without the Leica CloudWorx plug-in, we couldn’t do that.”

From there, Fries began building the 3D working model. Vehicle data, including speeds, distances and rates of deceleration, was provided by the accident reconstruction expert and then input into 3D vehicle models that Fries created within the software. The human factors expert supplied data on pedestrian movement, rates of travel, etc. Fries imported the positions of all of the physical evidence documented by the police immediately after the accident. This evidence data, which was collected with a total station, included victim and vehicle points of rest, skid marks, blood and clothing.

All of this data was overlaid and aligned to the laser scan data. “This interactive, three-dimensionally accurate model that we created from the laser scan data became the basis for every expert’s work,” Fries said.

Reconstructing the Accident

Typically, when Fries collaborates with experts, they interact with the 3D scan data in a 2D format. “They want measurements. How far is it from here to there? What’s the slope?” Fries said. “They ask very basic questions of the data.”

FireShot Capture - Precision Simulations Inc. __ 3D Workin_ -

However, in this case, the experts utilized the 3D laser scan data, including the captured colors, for all their analyses. “That’s something I do all the time,” Fries said, “but I’ve never seen an entire team of experts interact with it directly.”

In more than 100 hours of online conference calls meetings, dozens of experts from around the state viewed and experimented with Fries’ 3D working model. This unrestricted access to the virtual accident scene allowed the experts to finely hone their analyses as opposed to making general calculations. They changed speeds, widths, angles and trajectories, lines-of-sight, etc., until the outcome matched what was observed at the scene. “They were able to line up the exact strike and impact and scrape marks on the hood of the car and the windshield with the belt buckle that the girl was wearing—all of that in 3D, which you would never be able to do any other way,” Fries said. “That was revolutionary.”

Analyzing Causal Effects

In this case, the 3D working model was used not only to reconstruct the accident but also to determine causal effects. “We were honing our analyses with the environmental features—the trees and sun—and then combining the two of them together to see how one affects the other. If the trees had been cut by X, how would that have affected the driver’s behavior and, therefore, the outcome of the accident?” Fries explained. “That was something I hadn’t done before.”


To answer this key question, Fries undertook a shadow study within the 3D working model. His team returned to the scene to observe and record the environmental conditions at the time of the accident. “We did our reconstruction on the same anniversary date, at the same time of day, used the same pedestrian clothing, going the same speed in the same car,” Fries said. “Because the setting sun was in the driver’s eyes, we couldn’t see those pedestrians at all, even though we knew that they were there, until we entered that shadow that they were in and our eyes adjusted. That happened when we were only 40 feet away from where Bertoli would have been in the crosswalk, which is less than one second. By that time, it was far too late to avoid the accident.”

After photographing and video recording the shadow, Fries extracted the shadow from the video and precisely overlaid it in the laser scan model using a process called laser-assisted photogrammetry, which he pioneered in 1999. He then developed a program to animate the sun’s transit across the sky over a 12-month cycle. The animation demonstrated that the crosswalk was shaded nearly five months of the year. “It wasn’t a freak occurrence just on that day,” Fries said. “It was something that the state had plenty of notice of.”


Next, Fries virtually trimmed the scanned trees according to city, county and state codes, each of which had different trimming instructions. “We dialed up the sun to the right time and date and then looked at the amount of shade that was created,” Fries said. “Using laser scan data, we were able to prove that the shade was reduced significantly—enough to make a difference had those trees been cut to code.”

The shadow study gave Bertoli’s attorney the proof he needed to argue his case. “Without the 3D working model, the attorney would be left making the suggestion that the trees were a causal factor,” Fries said. “There’s not very much depth to that argument if challenged.”

Prolific Use of Scan Data in Court

When the case came to trial in 2015, Bertoli’s attorney continued his prolific use of the laser scan data to provide depth and clarity to his arguments.

He presented a comprehensive list of reasons why the crosswalk was dangerous. Bertoli had not been the first person injured. “Many other people had been hit in the same crosswalk,” Fries said, “and citizens had been complaining about it for quite some time.” For each argument made, the attorney queried the scan data and presented supporting graphics created by Precision Simulations. “So the entire trial—everything he put in front of the jury that was related to the accident itself—was visualized to the jury with laser scan data,” Fries said. “I’ve never seen that before.”

Additionally, every expert used the laser scan data directly or graphics created from it when testifying. And they used it to critique the opposition’s testimony. “Every single thing that the other side claimed was true was checked against the laser scan data and was found, in many cases, to be inaccurate,” Fries said. “Because we had the laser scan data, we were able to say to the judge, ‘This is inaccurate, not just because we say so or in general terms, but here is the specific measurements from the scan data that contradict what these other experts are saying.’”

Fries' laser scan data was an integral part of this case. “Almost every piece of this case relied on the original laser scan data to either determine the conclusion and or illustrate the results of the analyses,” Fries said. “This guy really understood the power of what he had when he saw the working model.”

A Precedent-Setting Move

Most demonstrative evidence—computer animations, laser scan data, expert opinion, etc.—is not admitted into evidence. “It is considered opinion and hearsay,” Fries said. “You can show it to the jury while you are testifying, but they don’t get to consider it when they are back in the jury room deliberating at the end of the trial.”

So Bertoli’s attorney took a novel approach. He attempted to move all the scan data—as well as the analyses based upon it—into scientific evidence. “That was a radical thing,” Fries said.

The move was met with vociferous opposition. “Of course, the other side fought tooth and nail,” Fries said. “We went around and around. Many motions were filed back and forth trying to keep it out and trying to keep it in. I wrote four declarations myself in defense of the data.“

Leica Geosystems’ published accuracy for the ScanStation proved critical to countering the opposition’s challenges. Fries explained: “If we were using another manufacturer’s scanner, I don’t believe we would’ve been able to show the necessary steps to get through their challenges about the validity of the scanner because we wouldn’t have had the published accuracy standards. And that was something that both the city and the state were very savvy to during their cross-examination. They clearly did their homework and probably hired a consultant on laser scanning to ask those questions.”

In addition to the manufacturer’s accuracy standards, Fries provided independent validation from Caltrans, one of the defendants in this case. Before adopting laser scanning into its survey operations, Caltrans hired the University of California Davis to assess the technology. The subsequent 2007 report, Creating Standards and Specifications for the Use of Laser Scanning in Caltrans Projects, validated the use of the technology and the specific use of Leica Geosystems laser scanners. “That went a long way towards getting buy-in from the judge about the scanner itself,” Fries said.

In the end, Fries laid enough foundation to demonstrate that the ScanStation provided highly accurate engineering data. “We were able to show that there is no bias, no human error, no storytelling or coloring or shading. It’s data,” Fries said. “Not only is it data but it’s data that’s critical to the jury to help them make their decisions in this case.”

The Leica ScanStation data was ruled by the judge to be scientific evidence generally accepted by the scientific community as reliable and accurate. The judge admitted into scientific evidence the scan data and the expert analyses built upon it, including the 3D working model, the shadow study and two 8-inch binders containing hundreds of exhibits—all of which was provided to the jury for deliberation. “That was a first,” Fries said. “I don’t know if that’s ever happened before. I can’t recall a case that I’ve been involved in where an attorney has ever attempted to do that.”

The Future of Laser Scan Data in Court

Because the laser scan data, as well as the analysis based upon it, was admitted into evidence, it is now accepted into the judicial record of the case evidence. “That’s a huge deal,” Fries said.

He explains: “Trial courts are all about precedents. Has it happened before? Yes or no? If it hasn’t happened before, you’ve got a massive uphill fight. But if the answer is, ‘Yes, I have, and here’s where,’ it makes it much easier to do it again in the future.”

From now on, Fries will be encouraging Precision Simulations’ clients to try and move the scan data and the analysis into evidence. “I will now be providing the case citation, the motions and the court transcripts to my clients saying, ‘We were successful in doing this,’” Fries said.

It’s a strategy available to Leica Geosystems’ customers, as well. "In the past, the jury didn't get to consider the scan data or the analysis when trying to decide guilt or innocence, liability and damages. They only got to hear about it one time when the expert was on the stand. Now, Leica scan data can become a common tool that the jury uses during deliberations,” Fries said. “This precedent is going to open the door for it to happen again and again and again."

To learn more about high-definition 3D laser scanning solutions for accident reconstruction and crime scene investigations, contact the Leica Geosystems PSG team.

To view the shadow study and accident-reconstruction animation, visit the Precision Simulations Inc. website.

About the author: Wendy Lyons is a freelance writer living in Canton, Georgia, and has a degree in journalism. Lyons was introduced to geomatics through her work as associate editor for the nation’s leading land surveying magazine.