Pipelines

Pipelines move oil.  It's a lot cheaper to push oil down a pipe than it is to load it in a truck.  There are problems with pipelines though.  They tend to stay where you put them, and the oil producing areas of North America are changing. 

Remember how the US's oil pipelines were designed primarily to move refined products from the Gulf region and the coastal refineries to inland customers? Well, those pipelines of yesterday now run the wrong way. Today what North America's oil machine needs are pipelines running from the oil sands to the Gulf Coast. At the moment there is just enough capacity to get bitumen partway there – it gets to Cushing, the oil hub. And then it gets stuck.

Great article explaining the pipeline infrastructure of the US and how the different in price between light sweet crude and Baaken sands oil makes a difference at the pump.