Sometimes it seems absurd that a smelly black liquid found in the ground can absorb media attention and elicit dire or hopeful predictions from world leaders. But oil is not just any old smelly liquid: It's an indispensable resource for all industrialized economies. As such, the price of oil has a tremendous impact on producer and consumer behavior.

For those of you who just stepped out of your caves, oil prices have been pretty high. Sure, Hurricane Katrina is to blame for the most recent spike. New York Mercantile Exchange crude oil futures, though, have been closing above $40 a barrel for more than a year. When oil prices will settle down even to that level remains an open question, especially as we approach winter with its added energy demand.

The recent elevated prices have been stimulating subtle responses in producer behavior, a fact most recently illustrated in Ford's (NYSE:F) announcement of an alliance with Italian automaker Fiat. The two firms will produce cars for the European market. While U.S. consumers may find gasoline prices exorbitant, they have nothing on Europeans, who have to pay heavy taxes on fuel. In some parts of the U.K., for instance, gas recently sold for almost $7 per gallon. Given that price, it's not surprising that Ford and Fiat will be developing two new car platforms for fuel-efficient subcompacts. To keep costs low, the cars likely will be produced in Poland.

Anecdotal evidence suggests that the two companies' move is part of a larger trend. As oil prices remain high, other automakers are becoming more interested in producing vehicles that are more miserly with fuel. General Motors (NYSE:GM) and DaimlerChrysler (NYSE:DCX) are belatedly getting serious about developing hybrid offerings. Meanwhile, Volkswagen and a Chinese firm recently announced a deal to create a hybrid automobile for the Chinese market.

For investors, the key will be singling out automakers that produce fuel-efficient cars with the style consumers want. The obvious leader in the hybrid market right now is Toyota (NYSE:TM), thanks to its uber-popular Prius. But the higher price tag of many hybrids vis-a-vis their gas-only counterparts also opens the door for firms able to produce attractive and fuel-efficient conventional automobiles.

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Fool contributor Brian Gorman is a freelance writer in Chicago. He does not own shares of any companies mentioned in this article.