Thom, 'fact check' the facts about why 18 wheelers use a diesel power engine. The diesel engine is 15% to 20% more efficient as a gas power engine. An 18 wheeler (class 7 & 8 trucks) have a 600 plus house power engines, that also has 1200 plus foot pounds of torque (the torque is what makes the truck able to pull the loads-20 tons or more). A gasoline powered engine would have to be 20% larger to get the HP and still fall short, way short, on the torque (check it out-FACTS are FACTS). A natural gas engine is another 20% weaker, and requires 15% to 20% more fuel (there is 15% to 20% less energy in natural gas, a simple check would be to Google electric generators- compare the kilowatts output for a diesel, gasoline, natural gas and propane fueled engines). The T-boon's are pulling a Con on you.
The 18 wheelers have 300 to 500 gallon tanks on each side (600 to a 1000 total gallons) and burn 3 gallons per mile. There is NO WAY you could put that equivalent of compressed liquid Natural gas on these trucks, plus, you'd need 30% more of it to get enough fuel to do the same work as a diesel engine can do. ALSO, ask ANY knowledgeable engine mechanic about the maintenance requirements for a Diesel, gasoline and natural gas powered engine (no Spark plugs on a diesel, 500,000 to 1,000,000 miles life, compared to 100,000 to 200,000 miles on spark plug engine).
Check the fact that if 1/3 of all the cars on the road in the USA got the same MPH as the VW TDI (diesel), we would not have to import mid east oil. Why is it, all the European high mileage cars are DIESEL?? Today's diesel engines, cleanest ones, have less NOX than the gasoline engines (the soot is captured carbon, they filler that out of the exhaust). Also, you can inject natural gas into a diesel engine to improve its MPH and cleaner exhaust.
Please do some research, like you do on 99% of you other topics or talking points?
Listening on AM 1090 Seattle or XM radio- everyday.