[porknubbins]

Say a tanker truck has a roughly 300 gallon fuel tank and a 10,000 gallon payload tank (per google). Thats roughly 3% loss to cross a lot of the US, which is by no means insignificant but assuming ships are not any worse and the pipeline to the ship is minimal, around a manageable 6% loss.

[ygra]

Trucks need a lot more infrastructure in a lot more places than ships, though. I guess that's not often factored in.