Actually, I had used this as my starting place with:
Evalutaion of 2004 Toyota Prius Hybrid Electric Drive System, R. H. Staunton, C. W. Ayers, L. D. Marlino, J. N. Chiasson, T. A. Burress, May 2006, ORNL/TM-2006/423, UT-Battelle
But roll-down tests would be impractical.
If I do this, I will put the front on jack-stands and some mechanism to keep the tires rotating at the same speed . . . some kind of hillbilly dyno. But I won't be putting 3,000 lbs of rolling, unpowered metal on the street.
Bob Wilson