During 2018, the Montana Highway Patrol started using drones and photogrammetry software to examine crash scenes. Officers say the tech has dramatically increased efficiency, safety and accuracy.
Investigating a car crash on the highway is a time-consuming and potentially dangerous proposition for officers when it's done on foot and with manual processes. With a drone, however, the time and danger are largely removed from the equation.
Shawn Hazelton, a sergeant with the Montana Highway Patrol (MHP), remembers more than 20 years ago when his agency didn’t even use a total station, an electronic surveying device, to map out a crash scene. Officers would spend hours measuring lines with manual tools. Not only would they come away with limited data, they had to watch out for traffic as they walked back and forth across a road.
“A lot of scenes that we did … it was me and one other guy, and that was it,” Hazelton recalled. “You would hope people would pay attention and slow down for your lights.”
Departments started using total stations during the 1990s. Even with the more advanced equipment, the job would still require multiple people, only about 150 data points would be collected, and the process would take about three hours, said Aaron Freivalds, MHP trooper and traffic homicide investigator.
Robotic total stations would later cut the investigation time by at least half and reduce the amount of required manpower, but officers still had to walk across the highway.
Now an investigator’s feet don’t necessarily have to touch the road. A drone with a camera can be flown by a single officer parked near the scene.
“I can go out by myself and process a quarter-mile scene in 30 minutes without interfering with the flow of traffic, without having to walk in the roadway at all, and then take those photographs back to my office and finish processing the scene remotely,” Freivalds said.
Freivalds added that Montana has distributed drones across the state so that as long as a pilot near the crash is available to fly an aircraft, an investigator doesn’t have to come to the scene if they are hours away from the incident.
To re-create the scene, hundreds of high-resolution drone photos are uploaded into a software program (Montana uses a product from company Pix4D based on ease of use). From there, the program creates a fully three-dimensional image via photogrammetry.
The final product, a 3D environment, is the best part about the whole process, according to MHP Trooper Philip Smart.
“A jury can really experience what the scene was like,” Smart said.
Compared to traditional recording tools, photos taken from the sky reveal much more about crash scenes. If a driver or passenger was ejected onto some grass during an accident, officers can determine where the individual initially landed by looking at where the grass has been pressed down, Freivalds said.
If an ejection occurs at night, Montana officers can utilize a thermal camera on a drone to locate the individual. This method can help people get medical attention more quickly. It also decreases the need for expanded search parties.
“Rollover crashes can be very violent,” Hazelton said. “People can be thrown 100 feet or more from a crash scene. We would use our wrecker drivers at times to start searching an area. At night, you could only search as well as what your lighting is.”
Smart pointed out that if a vehicle falls down a steep embankment into a river, it would be difficult to accurately capture the scene without the assistance of a drone.
“When you’re in a place with plenty of contour like Montana, having a drone is certainly useful,” he said.
For any drone crash investigation program, Hazelton recommends getting Part 107 certificates for all pilots and a certification of authorization (COA) from the Federal Aviation Administration. Part 107 helps protect pilots if they follow the rules, while the COA protects the agency by allowing it to fly in some controlled airspace.
Hazelton added that if an agency is required to purchase U.S.-made drones, it might cost tens of thousands of dollars for a single drone. Montana doesn’t have such a restriction, so it was able to acquire DJI drones for a little over $2,000.
Freivalds said it’s important to engage with the press and public about any drone program. Live demonstrations, though difficult to set up, can address many potential misconceptions about safety. Freivalds, who flies remote control planes as a hobby, added that drones are much easier to manipulate.
“If you take your hands off the controls, it [the drone] will hold its position,” Freivalds said. “If strong winds come up, a traditional RC plane would get pushed along with the wind, whereas these drones automatically compensate for the wind.”
Smart suggested there’s nothing not to like about using drones for crash investigations. When it comes to alternatives, there are scanners that can shoot lasers at everything and produce superior 3D images, but scanners have very limited range compared to drones, he observed.
Looking for the latest gov tech news as it happens? Subscribe to GT newsletters.