Recent declines in fuel prices are expected to continue into next year, according to U.S. Energy Department’s just released Short Term Energy Outlook.

U.S. on-highway diesel fuel prices, which averaged $3.92 per gallon in 2013, are projected to fall to an average of $3.86 this year and $3.82 in 2015, 2 cents and 5 cents lower, respectively, than projected in last month's outlook.

For the current quarter diesel is forecast to average $3.83, falling to $3.74 in the fourth quarter of 2014. Once 2015 begins diesel prices are projected to rise slightly into the second quarter before retreating, but the 2015 average should still be below this year’s expected average, due to high prices in the first quarter of 2014.

While these numbers compare to the most current weekly average U. S. diesel price of $3.814 per gallon, the department cautions daily and weekly national average prices can differ significantly from monthly and seasonal averages, and there are also significant differences across regions, with monthly average prices in some areas falling above or below the national average price by 30 cents per gallon or more.

Meantime, U.S. regular grade gasoline retail prices, which fell to an average of $3.49 per gallon in August, 12 cents below the July average and 21 cents below the average in June, are projected to continue to decline to an average of $3.18 in December, which would mark the lowest monthly average since January 2011 and is 12 cents lower than in last month's forecast.

The Energy Department also expects U.S. regular gasoline retail prices, which averaged $3.51 in 2013, to average $3.46 in 2014 and $3.41 in 2015, 4 cents lower and 6 cents lower than last month's forecast, respectively.

The expected drops in fuel prices come as U.S. petroleum consumption is expected to fall this year by 0.2% while distillate fuel demand, which includes diesel, is expected to increase 4.2%. Helping the anticipated decline in fuel prices is the expectation crude oil prices will drop more than projected a month ago, due in part to new pipelines delivering oil to refineries along the Gulf Coast and big gains in U.S. crude oil output.