Average vehicle fuel economy hit its all-time high [1], and there's been a massive cut-back in how much people drive [2]. Americans are driving less and when they do drive, they're driving cars that use less fuel per mile.
You can likely credit the fuel economy increase on the federal mandates for higher MPG ratings on new cars, and the cut-back in driving on the high unemployment and stagnant/falling real wages of the employed.
Whatever the cause for the drop in September/October 2011 was, that was only a drop in refinery sales, as gas sales at the pump experienced no such fall [3].
Thats not what the data represents. It represents sales by refiners to retail. That is buying gas from a Shell gas station (also a refiner) counts, buying gas from a mom + pop corner store who wholesale buys their gas from a refiner (or distributor) doesn't count. The graph seems to just say that some refiner sold off their retail gas stations (or something like that).
Alternatively, you can credit both the fuel economy increase and the cut-back in driving on higher gas prices, which can in turn be credited to rising global demand for gasoline.
You can likely credit the fuel economy increase on the federal mandates for higher MPG ratings on new cars...
I'm not sure how likely that is. Seems to me that when gas is cheap, people buy big, powerful cars (e.g. SUVs) with little regard to fuel economy. When gas prices rise, people buy small economical cars. People buy what they think they can afford and makes sense for them, and automakers make more of what the customers are buying and less of what they are not buying.
You can likely credit the fuel economy increase on the federal mandates for higher MPG ratings on new cars, and the cut-back in driving on the high unemployment and stagnant/falling real wages of the employed.
Whatever the cause for the drop in September/October 2011 was, that was only a drop in refinery sales, as gas sales at the pump experienced no such fall [3].
1: http://www.csmonitor.com/Business/2012/0223/Americans-trend-...
2: http://www.brookings.edu/research/reports/2008/12/16-transpo...
3: http://ycharts.com/indicators/us_gasoline_station_sales