Traffic insertion problem

Hello
I want to insert traffic to graphhopper.
regarding this post "https://www.graphhopper.com/blog/2015/04/08/visualize-and-handle-traffic-information-with-graphhopper-in-real-time-for-cologne-germany-koln/"
this Vague point for me is about the fetching data format (contain which information) and how parse those to data that garphhopper can use them.
Can i have your kind assistance to help how can gather traffic information and use it in garphhopper for traffic layer?
Best Regards

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