I heard all kind of tin foil hat stories regarding this issue. It is clear that trains are more fuel efficient, but yet trucks are the main method of freight transportation. I heard oil companies had something to do with this, lobbying for trucks (in the form of roads) in order to get profit. Is there any truth in these stories? Was there at some point in american history a push, propelled by oil companies, for the government to construct roads instead of railroads? This kind of information is extremely elusive, I couldn't find anything. Any help will be much appreciated.
Without getting at all into the history of how it developed, it isn't clear to me that your premise is correct that trucks are the main method of freight transport in the US.
According to the US Department of Transportation, 39.5% of freight ton-miles in the US are rail vs. 28.6% via truck (12% water, 19.6% pipeline and 0.3% air.).