Fleetwide Vehicle Fuel Efficiency

Doesn't seem like much of a mystery.

- Emission standards were tightened in the 1990s and again in the 2000s.

- Low gasoline pump prices allowed consumers to indulge in larger and larger vehicles (some of this might have been to more easily contain their more and more obese bodies and those of their progeny, and some of it might have been consumer fetishism of increasing size attempting to compensate for the increasing depth of the emptiness in their soul....or not) without feeling much financial pinch.

- Increased stop and go traffic and more air conditioner use in the often warmer summers in the 1990s and 2000s probably hampered mileage, though I'm not sure if the study was done on actual fuel usage and mileage, or assumptions about the vehicles that comprise the fleet.

It's people buying what they want and what they can afford. Funny how the free market works...

Inflation...inflation of "...fuel economy apathy...".