The U. S. on-highway diesel fuel price on 09/11/17 averaged $2.802 per gallon. Every region in the country showed significant increases. California once again was the highest at $3.179 per gallon. The Gulf Coast Region had the best price at $2.647 per gallon. The on-highway price is the highest price since 08/17/15. It is predicted to rise each week because of the destruction from Hurricane Harvey in the Houston area.