Sorry, the link doesn't get you any data unless you are a subscriber (only free videos and an overview). For risk of getting a talking to from my boss, here's some data on the Dodge Rams...

Without a trailer, we got 19mpg at a steady 65 mph and 13 mpg in mixed driving in both the Hemi 1500 Ram and the Cummins 2500 Ram (both crew cabs). But the 1500 went 0-60 1.2 seconds quicker, stopped 23 feet shorter in the dry, rode better, was easier to get into, had full-time 4WD, stability control, traction control, cost about $10,000 less, etc., etc.

We only saw and advantage with the Diesel when with a big trailer. With a 7,400lb enclosed trailer we got 8mpg with the Hemi vs. 10 with the Diesel at a steady 65mpg.