Petrol. In the USA the price of petrol is about US$3.50. Gallon. why?

Question

the vast difference compared with A$6.00 per Gallon?

Answer 1

The United States is very efficient at refining and transporting our fuel around the country through a network of pipelines and distribution points.

Answer 2

Compared to Australia, there is almost no tax on gasoline in the US.  Federally there is a US$0.18/gallon tax compared with a A$0.38/litre (almost A$1.50/gallon).  Add in some state/provincial taxes and the fact that gas is now closer to US$4.00 in the states and a small exchange rate benefit and that explains most of the difference.