But petroleum is also an ingredient in many other things, like tires. Most tires aren't made of natural rubber.
"There are made of a lot of synthetic rubber, a substance called carbon black, and other petroleum-based materials," said Yokohama spokesman Fred Koplin.
As the world looks for ways to use less oil, Yokohama is showing off a new line of tires that aren't made from crude oil, but the oil in orange peels.
"We eat the good part, and you have the peel left over. We take that, natural rubber, and we create a tire that has 80-percent petroleum-free content," said Koplin.
Yokohama says these are the greenest tires ever produced, and that they're just a bit more expensive, $3 to $5 extra per tire. They also have a special liner that keeps them better inflated, so theoretically they'll help with fuel economy too.
The primary applications for the new orange tire right now are hybrids from Honda and Toyota.
But they're available for other cars as well, like the sporty Mini Cooper.
"For a 'green' tire it performs well, and for a performance tire it's truly green," said Koplin.
They even use orange-based racing tires on some Porsche race cars.
Most would agree that making things out of organic materials is better for the environment. But the concern is that using something that's thought of as food to build non-food things would run up the price of food.
Well there's no danger of that here. What they say is that when orange juice is made, the peel of the oranges is just a waste product.
This green theme is working its way into other car parts too. The Ford Escape Hybrid has seats made from recycled plastic.
And Lexus is introducing interior plastics on some of its cars that are both recycled and recyclable. These innovations make so-called green cars that much greener.
But for all kinds of cars these new tires can help them use less oil, not just in the tank, but on the pavement.
