The solution to reducing and eliminating the USA's demand for OPEC oil (i.e., 5 million of 13 million barrels per day of imported oil) touted by T. Boone Pickens is the conversion of America's 18-wheeler trucking fleet to natural gas. See The Daily Show: T. Boone Pickens Extended Interview, January 27, 2011 (USA) or The Daily Show: T. Boone Pickens Extended Interview, January 27, 2011 (Canada). Although not specified exactly how this would be done, Pickens suggested that it would involve the gradual replacement of old diesel trucks with new natural gas fueled trucks. At this time, both CNG and LNG-fueled trucks are available for this market but LNG vehicles have the advantage of potentially longer range but CNG has the advantage of more refueling stations.
T. Boone Pickens noted that natural gas costs $4/MCF which compares with about 7 gallons of diesel which would cost about $21 (see 13:35/22.20 of the extended interview). This does seems like an excellent price but, from a survey of natural gas and gasoline prices, Clean Energy Fuels Corporation (founded by Pickens) CNG & LNG stations seem to charge about $0.50/GGE less than the going price for gasoline. Pickens also goes on to say that the main thing that is keeping the USA from moving to natural gas is political leadership. There is no mention of fuel availability, which would seem to be a much bigger issue.
Before going farther, it would useful to put fuel prices in terms of the Diesel Gallon Equivalent (DGE), which means the amount of natural gas that has the equivalent energy of a gallon of diesel fuel. It compares with a GGE ( Gasoline Gallon Equivalent), which is how CNG is commonly advertised at CNG stations (see NGV Calcs). Using US DoE CTA Fuels Table data, the energy content of natural gas is 983 BTU/CF LHV, the energy content of reformulated gasoline is 113,602 BTU/gallon, while the energy content of low-sulfur diesel is 129,488 BTU/gallon LHV. The amount of BTUs in an cubic foot of natural varies from well to well (and pipeline to pipeline) but 983 BTU/CF is in the ballpark. Therefore, an MCF of natural gas works out to 7.591 gallons of low-sulfur diesel. Using the ratio between the energy content of reformulated gasoline and low-sulfur diesel, 1 DGE = 1.14 GGE.
Using Los Angeles as an example, CNG at Clean Energy Stations is currently selling for $2.60/GGE ($2.96/DGE) while diesel is selling for around $3.85/gallon - a savings of about $0.89/DGE. LNG at Waste Management stations in the Greater Los Angeles area seems to be selling for about $1.70/gallon or $2.95/DGE. If CNG were actually selling closer to the pipeline cost of natural gas, $4/MCF would cost about $0.527/DGE or $0.462/GGE. If we add $1/GGE for O&M costs and profit, CNG would be selling for about $1.462/GGE or $1.667/DGE.