Data for the Heck of It, Hybrids vs. Gas prices

I'm working on a talk for a symposium in April. The topic is "Sensors for Transportation". Along the way I visited the Department of  Energy "Alternative Fuels Data Center" website. They have a host of accessible data showing everything from types of electric vehicles to average consumption prices of various fuels. Being that I'm a data enthusiast I thought I'd generate a silly plot of hybrid electric vehicle sales versus average US fuel prices.

 (left axis) U.S. Hybrid Electric Vehicle Sales compared to (right axis) Average U.S. Fuel (gasoline) cost per gallon. Data is from http://www.afdc.energy.gov/

The overlay suggests, as is probably obvious to many, that increased fuel costs result in more people buying fuel efficient vehicles. One might also make some other hypotheses from this plot:

• Fuel prices play a majority incentive in the masses buying more efficient vehicles.
• Thus, policy makers should maybe look to steeply increase gasoline taxes IF they want to truly expand AF vehicle market. Note: I'm not necessarily advocating, I'm just saying.
• Another option would be a AF vehicle purchasing rebate to make cost recuperation more immediate
• The incentive of being "green", while desirable to most, is not a sufficient incentive
• Those who control oil production/pricing also then have leverage to control the emergence of alternative fuel vehicles (i.e. OPEC)
• A caveat to this is OPECs "full capacity production ahead" was likely a push against alternative fuels policy making and while it was pleasant relief it likely stymied efficient vehicle R&D
• Vehicle purchasing is exceedingly short-sighted and is done largely with only current fuel cost in mind.
• Alternative fuel vehicles are a wise diversification for fleet vehicles to better average fuel prices.
• Fuel price guarantees may do the same, but could result in volatility near the expiration of the guaranteed price
• Bicycles are fun to ride, good exercise and only require fuel that is edible. :)