Montana Highway Patrol Uses Drones Located throughout the State for Crash Scene Investigations
BY Zacc Dukowitz17 December 2020
Crash scene investigation technology has come a long way in the last twenty years.
Photo credit: Montana Highway Patrol
When Shawn Hazelton, a sergeant with the Montana Highway Patrol (MHP), first started working as a crash scene investigator all of the work he did was manual.
He and his colleagues would spend hours laboriously measuring distances at crash scenes by hand, walking back and forth on the road where the accident took place.
Traffic would usually be stopped the entire time, so someone had to be devoted to managing traffic while this data was being collected.
This method of investigation was dangerous both for the officers and for those on the road. The chances of another crash—called a secondary crash—happening near the site of a crash is higher than under normal circumstances, and that chance goes up by 3% for every minute the original crash site isn’t cleared.
The window of time immediately following a crash is the most crucial—according to data from Purdue University, secondary crashes go up by a factor of 24 right after a crash.
If the crash site stays intact for hours while investigators collect data, that means the dangers continue to mount for everyone involved.
A lot of scenes that we did . . . it was me and one other guy, and that was it. You would hope people would pay attention and slow down for your lights.
– Shawn Hazelton, Sergeant with the Montana Highway Patrol (MHP)
This all means that officers have a tricky path to navigate when it comes to crash scene investigations.
On the one hand, it’s important for them to determine what may have happened at a crash site, but on the other hand, it’s important to clear the accident as soon as possible in order to prevent more accidents from happening.
But in the last few years, new drone technology has been helping to speed up crash investigations, allowing officers to clear accident sites more quickly than ever before.
How the Montana Highway Patrol Uses Drones to Investigate Crash Scenes
The Montana Highway Patrol first started experimenting with the use of drones for crash investigations about two-and-a-half years ago, in the summer of 2018.
Since then, officers have gone from testing the technology to regularly implementing its use at crash sites.
When an officer arrives at a crash site, they can put a drone in the air and begin collecting high-res visual data—images and video—that will be processed later using Pix4D to create 3D models of the scene using photogrammetry.
The 3D map can then be used to investigate the scene at a later date.
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.
– Aaron Freivalds, MHP Trooper and Traffic Homicide Investigator
Not only are drones quicker than other crash investigation solutions, they also have some unique added benefits:
- An aerial perspective allows investigators to see things that might be concealed from someone standing on the ground, like the location of a person thrown from a vehicle
- Thermal payloads allow officers to find crash victims at night, when it might be extremely difficult to do so otherwise
- An aerial view can also help recreate accidents in challenging terrain, such as vehicles that have crashed into a ravine or some other location that is hard to access
To support crash investigation needs in the state of Montana, MHP has made sure to have drones stored in strategic locations so that a drone pilot can come to a scene and collect visual data even if an investigator can’t be present.
The Evolution of Crash Scene Investigation Technology
Crash investigations have improved dramatically since Sergeant Hazelton first joined the Montana Highway Patrol, with new technology allowing officers to collect crash data more quickly and in a way that is more accurate and efficient.
But some of these newer methods can still be time-consuming.
With the use of a “total station”—an electronic surveying device that first came into use for crash scene investigations in the 1990s—a team of officers can process a site in about three hours. This is faster than manual methods, but still far too slow to avoid the danger of secondary crashes.
And the data collected by a total station, while better than that collected manually, is still fairly sparse, with only about 150 data points provided despite the long period of time required for its collection.
The next generation of the total station was the robotics total station, which came with features like auto-pointing, on-demand target reacquisition, and reflectorless EDM (Electronic Distance Meter). This solution required fewer people for investigations and it was faster, reducing the amount of time needed to process a crash site down to about an hour-and-a-half.
But an hour-and-a-half is still far too much time, from a safety perspective—if officers could close this window, they stood to make the roads much safer for everyone.
And this is where drones come in.
Photo credit: John Bullock and Erin Easterling/Purdue University
Here’s a quick look at how drones have changed the timeframe for processing an accident scene:
- Manual method—up to 10 hours, or more
- Total station—3 hours
- Robotics total station—1 and 1/2 hours
- Drones—5-8 minutes
Using a drone, an investigator can collect all of the data they need to conduct a thorough crash scene investigation in under 10 minutes.
This means that officers can clear the accident faster than ever before, improving safety for them and for those on the road.
Drones also reduce the number of people that need to be present to process the scene, and they present the added benefit of not requiring officers to walk the scene on foot (something still required by the robotics total station solution), which can be a safety hazard for officers.