
Read the Energy Security Council explanation of why oil is so important to the U.S. Take note of why access to oil is important and flex vehicles among fuel choices (ethanol, natural gas, electricity) to reduce this sensitivity (economic impacts). Not discussed is the improving of fuel economy (higher mpg). Also, note that imports of crude oil are often a cause of oil insecurity with sometimes drastic impacts (gasoline rationing). We now are the leading nation for crude oil production and have significantly reduced imports (more on this later) but are still linked to international oil trade and the growing oil demand internationally.

This link above seems to be having some issues. So please take a look at these two links:
Oil and Petroleum products explained (use of oil) Energy Information Agency The takeawy message being the importance of oil to the United States (heavy oil use).
How oil prices impact the U.S. economy (Investopedia) The takeawy message being the importance of oil to the United States economy