The Cd figure alone doesn't tell the whole story, though.
Frontal area is equally important, and drag area--frontal area multiplied by the drag coefficient, even more so.
Here, the scores even out a little. The large, boxy Leaf has a 7.8-square-foot drag area, the largest of any vehicle in the test.
The relatively compact CLA is next up at 7.0 sq ft, the Volt hits 6.7, and both the Prius and the much larger Model S feature a drag area of just 6.2 square feet. The Insight, on account of its tiny 20.1 square-foot frontal area (over 5 sq-ft less than the Model S) has a wind-cheating drag area of just 6 square feet.