Technological advances, along with relatively high crude oil prices, have led to sharply higher U.S. crude oil production. Historically, most crude oil has moved from production areas to refineries by pipeline. However, much of the recent increases in crude oil output has moved by rail. In 2008, U.S. Class I railroads originated just 9,500 carloads of crude oil. In 2012, they originated nearly 234,000 carloads and will likely originate around 400,000 carloads in 2013.