They forgot an important one in their tests: driving the speed limit. The difference in MPG while driving 65 MPH, versus driving 80 MPH, is probably as significant as the "leadfoot" situation.

This seems so blatantly obvious, but always seems to remain unspoken in the "how to save gas" articles I have read. Given that they broached the touchy subject of "leadfoot" versus "featherfoot", I'm surprised they didn't do a test related to traveling at the posted speed limit.