TrafficSurvey – Video post-processing platform

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Intertraffic 2024
16 - 19 April 2024
Amsterdam / Netherlands
22 - 23 May 2024
Coventry / England
Let's meet!
Intertraffic 2024
16 Apr -
19 Apr 2024
Amsterdam / Netherlands
22 May -
23 May 2024
Coventry / England

Assessing roundabout safety in Denmark

Road safety is critical for both pedestrians and cyclists. To take the right steps towards increasing it, municipalities need to take data-driven decisions. The town of Slagelse in Denmark, striving to improve their roundabout safety, asked their partner COWI to analyze the situation. To get profound analysis, COWI utilized AI based tools by DataFromSky.

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Project highlights:

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Easier analysis

Thanks to advanced filtering options of TrafficSurvey, our partner COWI was able to get rich insights in no time.

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Result evaluation

Our AI-powered speed measurement helped COWI to assess the impact of proposed improvements.

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decrease in car speed was detected thanks to the newly installed speed bumps.


Since the beginning, the municipality council had to handle the ever-changing environment in the town. The main concern the council keeps on the top of their mind is safety on their roads. That is a bit more challenging due to the popularity of using bicycles in Denmark. Cyclists are vulnerable road users so the council is applying different measures to keep them safe from accidents with cars.

This specific roundabout was just a part of their traffic safety initiative across the whole municipality. There were multiple traffic accidents with cyclists on this road, so the task was simple – make the roundabout safer
based on the actual hard data.

About the customer

Use-case: Traffic safety
Vertical: Municipality
Location: Scandinavia
Products: TrafficSurvey

About Slagelse

Slagelse is a town located on the Zealand island in Denmark, being approximately
100 km from the capital Copenhagen. The town has more than 35.000 citizens and covers area of 16,2 km2. History of the town dates back to 10th century.

Utilizing video analytics

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To increase the safety of the roundabout, it was necessary to understand all the transport participants passing the roundabout every day. The municipality approached a traffic engineering company COWI to conduct the study and suggest improvements. Back then, COWI already had significant experience with drone traffic safety analytics, so they decided to apply this successful method to get accurate traffic data about the roundabout.

Thanks to fully automated DataFromSky TrafficSurvey service, COWI received accurate trajectory data about each road user from the recorded aerial videos. They uploaded the file to fully automated online platform, applied geo-registration and requested 100% guarantee service to reach the ultimate precision in the traffic data. Geo-registration allowed to analyze distances and speeds of all objects during every millisecond of the footage and a 100% precision guarantee ensured that all the traffic objects are tracked.


After recording the first footage with the drone, COWI was able to set up advanced filters to get the desired data outcome for their analysis. They found out the average speed on the roundabout was 24,7 km/h. Based on that, COWI suggested the municipality of Slagelse installing speed bumps on each inbound and outbound lane to and from the roundabout. 

After the installation, COWI conducted another drone shooting to do the post-analysis and provide a full report according to the municipality requirements. The positive change was obvious as the average speed had been lowered to 13,7 km/h, proving a significant reduction. Details of the analysis can be found in the chart, where the data are visually presented.

COWI could simply fly the drone to do the recording and set all the analysis filters afterwards thanks to the DataFromSky TrafficSurvey. That helped them reduce the time for the project preparation and gave them more flexibility in adjusting the outcomes. To make sure the road behaviour changed, COWI conducted recordings before and after the speed bump installation.

"The precise DFS statistics and flexibility of the filter setup made it easy to understand the pain point and to prove the security increase in the municipality."
Jonas Olesen
Jonas Olesen
Head of the Project, COWI