[Dominik]

It has been done with an accelerometer on a know road (profile).

Yes: you accelerate, take reading. You decelerate (coast down) to get your baseline of resistance. From 120kph rolling resistance is small in comparison to aerodynamic drag.

We took 2 readings per front wheel revolution. OPEL tested their faster cars there too, like DTM and Lotus Omega.

My number look similar to the ones posted above. I pdf'd the Excel (one page) but the file size exceeds the limit. I try to send to ERA Chas.

I also aim to upload a pic here. It was a UK RAM with Hardtop, no side windows.
My passenger was very heavy, so we got 1.250kg as weight with the equipment.

Pics not working, I guess I can add them to my photo library?