I don't think this test is any more representative than the AAA winter test, but for opposite reasons. Temperatures weren't very cold (no more than a few degrees below 0°C) so heating requirements were modest and heat pumps were fully functional, and there was a lot of long distance driving at slow speeds. Some roads pictured were snow-covered (which would cause an increase in rolling resistance), but others looked like smooth sheets of ice - no wonder they were driving at 50-60 km/h much of the time.
A heads up for anyone trying to read the google translated version: when you see "mile" as a distance unit, it is a Scandinavian mile (10,000 m), not an English / US mile (1609 m).