Approaching traffic data integration: averaging

I am planning to integrate traffic data into my GraphHopper server by modifying the speed of edges. I am thinking about taking averages from historical data first, because that seems easier to me and except for accidents it might already do a good job. But, I somehow have to solve the time dependency problem, either by modifying the edges during the day (which requires a separate source of traffic data) or by creating a separate GraphHopper instance for every hour of the day, each having time specific edge speed values.

Any thoughts on this approach?