With all the commotion lately of pipelines closing and/or leaking, perhaps its a good time to answer the question- how do pipelines work?

There are hundreds of thousands of miles of pipelines in the U.S. that carry just about every imaginable petroleum product- oil, gasoline, diesel, jet fuel, heating oil, and more! Some of these pipelines are massive systems that can carry millions of barrels of oil per day, supplying not only refineries with the oil they need to refine into gasoline, but then shipping the finished gasoline from the refinery to local terminals.

According to the Association of Pipe Lines (AOPL), "Pipelines are the safest method of transporting fuels, as pipelines have the least amount of releases of any transportation mode. Liquid pipeline spills along right-of-ways have decreased over the past decade, in terms of both the number of spills and the barrels of product spilled per 1,000 miles traveled. For every barrel of oil (42 gallons) shipped 1,000 miles, less than one teaspoon is lost from a liquid pipeline."

"Liquid pipelines transport more than 17 percent of freight moved in America, yet pipelines only account for 2 percent of the country's freight bill. Only 2 to 5 cents of the cost of a gallon of gas to an end-user can be attributed to pipeline transportation, resulting in a low and predictable price for their customers. Significant competition among oil pipelines and other transportation modes keeps prices reasonable. "

So... having said that, its time for a video! HowStuffWorks presents History of Transportation: How Pipelines Work