It's an environmentalist site.
They can be trusted to give us accurate information regarding gas mileage, pollution and a return to the dark ages.
HIGHWAY gas mileage stickers are actually quite accurate.
Whatever they post on the sticker for highway speeds is tested at HIGHWAY SPEEDS... often 75 mph or so.
the 55 lie was a carter era attempt at cooling down the nations economy, cars were not aerodynamic as they are today, nor were they geared to wind as tight....
things are a LOT different.
the data being posted at enviro sites is propaganda.
Highway gas mileage stickers are based on an EPA test conducted on what amounts to a treadmill at an average speed of 48mph. There is no air resistance and unrealistic rolling resistance. Accessories such as AC are off. Acceleration is limited to about 3mph per second, or 0-60 in 18 seconds. To try and account for these inadequacies, results are then tweaked downwards by an arbitrary 22% irrespective of model.
The test is so divorced from actual driving as to be absolutely meaningless to the consumer, and the occasional instances where EPA numbers match real driving are purely coincidental.
Actually, and I can find the link if you like, the EPA hwy mileage ratings are based on a loop that involves some speeding up and slowing down, and a top speed of 55. The test simulates a 10 mile trip and averages 48 mph. At steady speeds, like out on the interstates in rural areas, especially with the cruise control set, many cars can do better than the EPA hwy ratings at speeds of 65-75.