Deploying ScanStation Speeds I-75 Reopening and Aids Investigation After Fatal Overpass Collapse

Sergeant Mike Miller’s cruiser was positioned on southbound Interstate 75 about 20 yards away from the Hopple Street overpass in downtown Cincinnati. He was working as an off-duty safety officer the night of January 19, 2015, while lane closures were in place for the demolition of the obsolete left exit ramp off northbound I-75. “There were cones and barrels set up,” said Miller, supervising sergeant of the Cincinnati Police Department’s Homicide Unit and Criminalistics Squad, “but my car was like the physical barrier with its flashing lights and the big fat POLICE on the side that would make sure motorists slowed down.”

Above him, construction workers were clearing the concrete deck from the structural steel on one side of a vertical support. As Miller watched the excavator move back onto the non-demoed portion of the road surface, the center span of the exit ramp suddenly collapsed onto southbound 1-75. “Going down, it met in space and time with an 18-wheeler and stopped it in its tracks,” Miller said. “The trailer of the semi, which was next to my car, literally went up in the air—you can imagine if you throw a Matchbox car against the wall, the back ends pops up. That’s exactly what happened.”

Seconds later, the east span collapsed. Miller thought the trucker was dead. But as he radioed for help, the driver emerged from the cab. “He had some bumps and bruises,” Miller said, “but it was amazing that he was alive.”

The emergency response

Miller immediately began orchestrating the extensive emergency response. He called for police officers in marked cars to close the highway and redirect traffic. He had fire companies come with heavy rescue equipment and ambulances staged while hospitals were notified in the event of additional injuries. He requested the traffic unit along with additional detectives to sequester and question witnesses. “Cops always talk about their training kicking in,” Miller said. “I wasn’t thinking about what just happened. I was doing my critical tasks to get resources there to help.”

As first responders arrived, Miller and construction workers assessed the scene. They were able, due to the channels at the end of the bridge, to confirm that no vehicles were smashed underneath. However, as they climbed onto the decking, they confirmed one fatality. Tragically, one of the construction workers  had been standing on the center span when it fell. “The excavator, which is a huge piece of equipment, had been secured onto something,” Miller explained. “So when the bridge decking fell, the excavator didn’t fall immediately. The slight delay was enough for this poor fellow to slide underneath. It fell on him and killed him.”

Capturing an immense and dynamic scene

Shortly afterward, the assistant police chief—unaware that Miller was already at the scene—called Miller’s cell phone to put him in charge of documenting the collapse. “We have the expertise and the personnel trained properly to do a mass scene like that,” Miller said. “So I brought everybody out, and we began the process of documenting through photography and the use of the laser scanner.”

Miller’s decision to deploy the scanner was automatic. “We needed to scan the scene because it was going to be our greatest chance to capture as much information as possible before they had to clear the roadway,” he said. “So it only made sense to me that it was the only option.”

Miller and his team worked through the night into late the next day. Two criminalists operated the Leica ScanStation capturing data from 11 positions around the bridge at medium density while another team of two took photographs. “After that, we called the police helicopter down and sent the criminalists up to do aerial photography so we could provide high-quality images from above to link together with all the point cloud data,” Miller said. “Whatever investigative response there was, we wanted to make sure we had as complete a picture for folks as possible.”

Miller knew that the investigators and engineers studying the failure would have a limited window to observe the collapsed overpass in its final rest position. “This was the opportunity to show them to-scale as if they had been at the scene,” Miller said. “If they wanted to take measurements, they could do it within the point cloud. They could get whatever images they needed from our photography, from the point cloud as it had those images laid upon it, and from the aerial views, so they could get whatever aspect ratio, whatever formula they needed to apply to it to understand the failure. It was all there. It was all captured. It was ready for them to use.”

Scanner speeds reopening of highway

The scan data not only virtually preserved the scene for future investigations but also facilitated the speedy reopening of one of the busiest highways in the nation. “When you have an interstate such as I-75,” Miller said, “you can’t hold that scene long. It must be reopened.”

After just eight hours of scanning, the scene was released and the construction firm began clearing the highway of the debris. “The best guess for reopening was three days right out of the gate before we started,” Miller said. “And that was a collaborative guess by folks who were engineer types, not just a dumb old cop like myself. The scanner saved tons of time. Had we not used the scanner, we probably would’ve been right around that three-day mark quite frankly.”

Miller has been involved in major crimes for a very long time, and he’s seen dynamic scenes captured in an analog way. “It takes an excruciatingly long time,” he said. “And then when it’s all said and done, if you didn’t make the correct annotations on your triangulations, then your diagram is off. So we were not rendering diagrams that were to-scale. We’d always have the annotation, ‘Not to Scale.’ With the Leica ScanStation, we’re actually to-scale to an acceptable variance. And the massive scene was manageable with just one scan team and one forensic team doing the photography. So this entire scene was captured and documented, in essence, with four criminalists.”

From the time of collapse to the point where southbound Interstate 75 was reopened was less than 24 hours. “That is pretty impressive when you think about the size and scope of what happened,” Miller said. “ODOT officials were amazed.”

Scan data is focal point of multiagency investigations

Back at the office, the 11 ScanWorlds were united via a manual cloud-to-cloud registration routine.* The billions of points of data, which stayed as a point cloud overlaid with scene photography, became integral to the extensive multiagency inquiries that followed. “There were several investigations launched that are a point of protocol in the engineering world for why engineering structures fail,” Miller said. “They all used our data for their investigation needs.”

Officials from several agencies—the Ohio Department of Transportation, the National Institute for Occupational Safety and Health, the Occupational Safety and Health Administration, the Ohio Attorney General’s office and the construction firm—came to the police department to study the scan data and photographic evidence. “We set them up with an oversized monitor and a computer. I gave them a criminalist familiar with Leica Cyclone software who sat there to help them get whatever view they needed to get from the point cloud, extract measurements, and do everything they needed to do,” Miller said. “We had people here for days, and the scan data was the focal point.”

“It was part of a larger response where they actually looked at all the metal involved in the failure. They couldn’t look at the concrete because that had to be removed in order to reopen the highway. The I-beams remained that were part of the bridge. The cleats on the vertical supports remained. The vertical supports themselves, the pylons, remained. They had site visits where they would go through and see hands-on those connections, but it was the scan data that allowed them to see where something fell, its exact location, how it related to the pylons, how far away the decking moved from the pylons, and that sort of thing.”

Conclusions of investigation

In May 2015, OSHA released the conclusions of their investigation stating that the demolition plan prepared by the construction company’s engineers was flawed and led to the incident. No criminal charges were filed. The collapse was treated as an industrial accident.

Though the Cincinnati Police Department’s Homicide Unit and Criminalistics Squad had never documented a construction failure of this magnitude, Miller knew the Leica ScanStation was the right technology for the job. “When you deal with something dynamic, scanning is the way to capture everything. And much like a crime scene would be, in that particular engineering failure, they didn’t know a lot that first day, but they sure as hell learned a lot over the following weeks to the point that they could identify the point of failure,” Miller said. “And I would like to think that that scan data contributed directly to that finding.”

To learn more about high-accuracy mapping solutions for law enforcement and crime scene investigation, contact the Leica Geosystems PSG team.

*Cyclone 9.0 and newer versions automatically align and register scans upon import.

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