Norwegian government saves time and money on road surveys with VTOL drone data [ROI study]
The Norwegian Public Roads Administration (Norwegian: Statens vegvesen) is a government agency that oversees the national and regional road network spanning the longest country in Europe. It has earned Norway the title of having the safest roads in the continent from 2015-2017, and the team aims to reach a zero-fatality goal. This goal is to be achieved by 2024, and a big part of enabling it is road creation and inspection.
Engineers at the administration have begun to use drones for road surveying, which is transforming the way they work in the field and the quality of data that they can gather on-demand. They’re also reporting budget benefits.
- Infrastructure maintenance, Road monitoring
- Norway
The administration started using WingtraOne last year for regular, broad-coverage VTOL drone road construction surveys, and they’ve already cut project time and spending significantly.
Cutting field time: from 5 days to about an hour
Gry C.S. Kjellsmoen is a chief engineer at the administration and flies the drone once or twice a week. She says smaller projects take just 15 minutes, while larger ones can take up to two hours. When comparing this to traditional survey methods and to a multirotor, it’s obvious why the administration just purchased their second WingtraOne mapping drone for their Oslo branch to conduct road and highway construction surveys.
When asked about the time cut from traditional methods, Kjellsmoen explained that a road survey covering about a 5 km (3.1 mi) requires three WingtraOne flight plans, lasting between 18 and 22 minutes each. This adds up to approximately one hour of flight time.
Traditionally it would take me about five days in the field with a scanner to get the data we get in an hour with WingtraOne, and then I’d have to edit it inside afterward.
Gry C.S. Kjellsmoen
Chief Engineer, Norwegian Roads Administration
The best drone for road construction
Before WingtraOne, the administration used a multirotor for a short time to collect drone data and prove the value of it. But the coverage was no match for the average road construction survey.
As a public service, they invited students to conduct drone surveys on a 1.5 km (0.9 mi) stretch of road with a DJI Phantom 4 that they used before WingtraOne. The exercise offered a direct comparison of the two drones.
For the flight of 1.5 km with WingtraOne, we had one plan that took 14 minutes. And with the Phantom 4 we had five flight plans of 10 to 15 minutes each.
Gry C.S. Kjellsmoen
Chief Engineer, Norwegian Roads Administration
WingtraOne vs. a multirotor on a 1.5 km (0.9 mi) road construction survey
| WingtraOne | Multirotor | |
|---|---|---|
| Flight number | 1 | 5 |
| Flight time | 20 minutes | 2 hours |
| Processing time | 3 hours, 57 minutes | 7 hours, 48 minutes |
Kjellsmoen said that, although exact times around mission planning for the multirotor are not available, it was significantly more due to the need for five separate flights. The quoted WingtraOne flight time includes mission planning.
How to conduct a road survey
- Map the area to be paved
- Plot all road features—street lights, manholes, cables, ITS, curbs, bypasses, etc.
- Monitor construction over time to compare plan to actual and reconcile contracts
- Document project in the national road database
- Deliver data to the public map authorities to keep information updated
Today, according to Kjellsmoen, there is no more cost-efficient way to collect, use and share this information than with drones.
Time (and accuracy) is money
Kjellsmoen flies WingtraOne’s RX1R II camera with PPK at 100-120 m (328-394 ft) altitude and uses government base stations to correct accuracy down to about 2 cm (0.8 in) absolute accuracy. The administration is looking especially at the volumes of Earth moved and tracking these as tightly as possible across projects.
“We use the drone data to see how much stone and sand is moved in and out. We have a database with information about all the roads in Norway,” Kjellsmoen said. “We also use it to control the data and check that it’s correct.”
One of the key ways drone accuracy proves its cost effectiveness is in its ability to help reconcile contractor estimates. The administration hires contractors to build roads. With drone data, it’s easier, faster and much more accurate to compare work estimates with what is actually happening.
WingtraOne’s dependability, fast flight and processing time enable regular orthophoto maps, which are a massive improvement on the point cloud data they used to collect with terrestrial survey methods. And the frequency of these road construction surveys brings everything into context.
WingtraOne helps us to follow up with the contractors building the road. We can agree on estimates, how the work is going and how much money is to be paid for it. We have everything they did in detail, including how much debris was moved.
The future of surveys is on-demand
In order for contract reconciliation to make a difference, surveys must happen frequently, which renders classical aerial survey methods too expensive.
The administration had also looked into helicopter surveys, which run about 11,000 USD more than drone surveys for a 5 km stretch of road. At this price, the frequency would be too low. Kjellsmoen said the team can gather complete data sets more often with a drone.
“We would not order a helicopter twice a week to follow up on a project,” she explained.
Cost of a single 5 km (3 mi) road construction survey
WingtraOne
Multirotor
Helicopter
Terrestrial laser scanner
USD figures estimated conservatively based on ~1000 NOK (108 USD) per hour wage and helicopter flat rate per survey. Both estimates quoted from administration source. Set-up time for the multirotor will be significantly more due to more flights. Multirotor set-up time estimated as a ~2 hour block vs. a ~1 hour block for WingtraOne, conservatively. Post processing for all methods not included, but is less with WingtraOne due to a streamlined post-processing workflow (see WingtraOne-multirotor comparison above).
Higher accuracy, and no belly landings
When the administration wanted to upgrade from their multirotor drones, they researched a traditional fixed-wing. But belly landing was not an option, so they looked further. WingtraOne, with its VTOL capabilities, high-accuracy payloads and coverage seemed like the right fit, and over time it proved itself.
Kjellsmoen says she and her team are satisfied with the efficiency and ease-of-use of WingtraOne, including the straightforward workflow.
The administration has invested in a robust computer station to run the software and process the data-rich images into maps and insights. Over time, WingtraOne has emerged as a solution for her team’s immediate needs and those of other departments as well.
“When I’m out with WingtraOne, if one of the geo-technicians wants to see something, I can fly for them and they can see what’s happened,” Kjellsmoen said.
Another advantage of Wingtra is the VTOL. We looked at fixed-wing drones, but they need a passage to land, and we often have small places for landing. We can take off and land everywhere with WingtraOne. It’s really good.
Gry C.S. Kjellsmoen
Chief Engineer, Norwegian Roads Administration
New corridor mapping and better wind performance
With the Oslo branch now up and flying, the administration has benefited from Wingtra’s corridor mapping feature, which specifically enables easy mapping of long, narrow passages. Kjellsmoen said that they are happy with the feature. She also said Wingtra’s latest updates for wind tolerance and tipping prevention have made a noticeable difference.
“WingtraOne generally handles wind well. In the past, we had just one tipping. After the latest update, we have had no tipping or issues in the wind. Here, inland, we have winds from 5 to 7 m/s (11-16 mph) and we have no problems.”
The administration has adapted its workflows increasingly around the new level of clarity that professional VTOL drone data provides. With continuous improvement and feature upgrades, the benefits WingtraOne offers will only increase. So could there be a larger fleet on the horizon?
Yes, I think we will expand more. It’s a long country!
Gry C.S. Kjellsmoen
Chief Engineer, Norwegian Roads Administration
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