A little while ago, Skyward hosted a webinar with the West Virginia Department of Transportation (WVDOT). We discussed WVDOT’s drone program and the great ROI they quickly began to see. Now we want to take you inside one of their primary use cases. Here’s how WVDOT used drones to transform what has always been expensive, accident-prone work — surveying aggregate stockpiles — for gains in accuracy, efficiency, safety, and cost savings.
Getting buy-in for drones at the DOT
When launching their program, WVDOT was able to follow in the footsteps of the state’s Environmental Protection Agency, which was already regularly using drones for watershed delineation and reclamation work estimates. Nevertheless, WVDOT was wary about the potential risks and liability of using drones.
“If someone on a road crew dropped a wrench off a bridge and it busted a windshield on a car below, everybody knows our insurance would pay for that,” explains Travis Long, chief of surveys at West Virginia Department of Transportation. “And other than that person’s supervisor and maybe one level higher, no one would hear about it. But if I did exactly the same amount of damage to the same windshield with my drone, the incident’s going to go all the way up the chain to management, and it’s probably going to make the news, because it’s new technology.”
With this kind of attention on the program, Travis and his team put a big emphasis on making sure they had the right pilots. They hand picked their team, pairing pilots with experienced surveyors.
The WVDOT drone team also emphasized starting small and not reinventing the wheel while gaining initial approval. Travis’s advice was to “Get through the part that none of us likes to do — the policies and the standard operating procedures — and get that done quickly. Borrow from what others have done and make sure you tailor it to what fits your program.”
Using Skyward’s software to manage drone operations
WVDOT began using Skyward’s Drone Management Platform to manage all their flights, pilots and equipment. When they needed to fly missions in controlled airspace, they also used Skyward’s software to submit LAANC requests for access to controlled airspace. This helped Travis keep track of WVDOT’s drone program no matter where his pilots would be flying that day.
“Without a system for tracking our flights, it became evident very quickly that we couldn’t keep up, especially as we began to add pilots,” Travis said. “You really need to have your finger on the pulse and know what’s going on statewide so you can answer any questions you get about your operations.”
Surveying stockpiles more accurately, safer, and faster
During the drone program’s early stages, surveying some of WVDOT’s 177 aggregate stockpiles was one of the first use cases.
State highway departments store large piles of crushed rock, sand, salt or gravel, used for road building, maintenance, and winter traction. We’re talking a lot of aggregate: it takes roughly 25,000 tons of crushed stone per mile to construct a two-lane asphalt highway.
West Virginia’s stockpiles include about a dozen classes of materials. These stockpiles must be physically surveyed annually to get an inventory. Until drones, such volumetric calculations have been done in a few ways. One was counting the number of trucks carrying bulk material coming and going, a method that one company found can cause inaccuracies of much as 20 percent. Another was having surveyors measure the piles, requiring them to climb around hazardous stacks of shifting material.
“It’s always been a project that none of our surveyors like to do, because walking on gabion piles is a good way to break your ankle or some piece of equipment. And then nobody believes the data because they’ve been counting trucks or tonnage,” explains Travis. The West Virginia ODOT survey team saw drones’ potential to speed up this process, reduce risk, and increase accuracy.
Travis’s team invested $25,000 investment in equipment and pilots and set up a model to verify the data they collected. Crews flew drones around stockpiles and quickly captured extensive imagery. These images were stitched together with software that builds 3D models of the piles, which can then calculate their volume. After taking physical measurements to check the model, the WVDOT team found the drone measurements to be remarkably accurate, which impressed Travis.
Not only that, but the work was completed more than twice as fast as traditional surveys.
“We would typically have 21 survey crews working on this project, and it would usually take right around three weeks to complete it,” said Travis. “When we took it on with drones, it only took us nine days to collect this data, process it, and report results. This is the best way to survey stockpiles.”
Calculating ROI for drone stockpile surveys
The strong return on investment the West Virginia team demonstrated early on gave the program traction. WVDOT calculated their returns by comparing the cost of conventional surveying of stockpiles with surveys using drone technology. The conventional method took 42 surveyors 15 workdays, at a cost of about $378,000. With drones, the same workload took seven drones pilots only seven workdays, costing about $35,000. The department saved $343,000 in a single month.
These cost estimates don’t include additional benefits, such as fewer risks to the workforce, higher frequency of surveys, and less equipment needed.
(Pro tip: to calculate your organization’s potential ROI on drones, try Skyward’s ROI calculator.)
Next: expanding to other use cases
Since aggregate is one of the biggest materials used in construction projects, stockpile inspections are a logical first drone use case for many public agencies. In fact, about 50 percent of all aggregate is used for publicly funded construction projects. That includes highways, water and sewer systems, public buildings, airports and other county and municipal public works projects.
Other common department of transportation uses for drones include traffic monitoring, disaster response, construction progress updates, ice control, snow removal, and inspections of pavement, high-mast light poles, and bridges.
WVDOT is considering expanding its drone program to additional jobs:
- Construction material cost estimates (quantity takeoffs)
- Surveying and topographical maps as part of designing new road routes
- Road safety assessments using point clouds
- LiDAR surveys for even higher accuracy
Drone stockpile surveys: less than half the cost, more than twice as fast
WVDOT’s experiment in using drones for stockpile inventory quickly expanded to a department-wide program. In West Virginia, drones are delivering survey-grade accuracy in a fraction of the time at half the cost of conventional inspections. Other state transportation agencies are also discovering that the return on investment in drones technology is attractive regardless of state geography and size, from populous states like Ohio and Minnesota to small, rural states like West Virginia.
Wanting to launch a drone program at your agency or company? Check out the Skyward Guide to Starting a Drone Program.