Wednesday, July 30, 2008


Miles Per Gallon Regular Unleaded Gasoline vs Price

1976 to Present

CPI from here.


UPDATE: Recalculated with Diesel added in.


Miles Per Gallon

13 Month Moving Average

Vehicle Miles Driven is from DOT.

Gasoline Consumption is from EIA.

My guess is that DOT over estimates VMT and/or EIA under estimates product supplied, leading to the high MPG calculated.

What's important here is the trend.

UPDATE:Finished Motor Gasoline doesn't include diesel. New numbers with diesel here.

Tuesday, July 29, 2008


Trends in Fuel Efficiency

Fuel Efficiency is higher now than back in 1998. Efficiency Declined from 1998 unitl the end of 1999 and then improved quickly. It remained relatively flat until 2004 and then began improving until the middle of 2006. Since 2006 fuel efficiency has been in steep decline.

(Data is from EIA and DOT. The graph is of % change from one year prior in vehicle miles driven minus gasoline consumption % change summed for each month since Jan 1998)

Friday, July 25, 2008


Rational and Irrational Reaction to High Energy Prices

Bryan Caplan links to a snippet from Richard Posner on people's resonses to high gas prices.

I wonder, too, whether the recent decline in U.S. gasoline consumption doesn't represent to some degree an irrational panic reaction. To take a huge loss on the sale of your SUV in a market that is depressed because so many other people are doing the same thing at the same time is unlikely to be justified by the gains from the improved gas mileage of the car you buy with the modest proceeds of the sale. Likewise, driving a substantial distance to save a few cents a gallon on the gas you buy is unlikely to be worthwhile. A recent article suggests that people fixate on the price of gasoline because unlike most regularly purchased items, such as food, gasoline is purchased separately from other items so that its price is not buried in a bill for multiple items.

Pile on top of that, entirely rational reasons fuel efficiency may decline with higher gas prices.

And, it gets worse. From CNN, communities are cutting back on public transit, police, and road maitenance.

Food prices are greatly affected by oil. It accounts for most of the production cost.

Fuel consumption is declining much less than driving is.

Not to worry, people are discovering ways to reclaim their lost efficiency.

The last time there was a significant reduction in gasoline consumption was 17 years ago.

17 and a half years ago, there was an upward spike in oil prices in August 1990. It was followed by a recession from Sept 1990 to Sept 1991.

Tuesday, July 08, 2008


Gasoline Consumption and Vehicle Miles Driven

As a percentage of the same month, one year earlier.

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