The national average price of diesel fell yet again over the past week, to $4.145 a gallon, according to the weekly report from the U.S. Energy Information Administration.

That's a 6.2-cent-per-gallon decrease from the previous week, although prices are $1.282 higher than they were a year ago.

This is the sixth week in a row the EIA's weekly average has dropped, since hitting a record high of $4.764 per gallon in Mid-July.

The most expensive average retail prices were found in the New England region, at $4.382. The lowest were in the Midwest, at $4.073.

However, the Oil Price Information Service warns against getting too optimistic about lower fuel prices. "Despite the decline and some presently bearish sentiment, many experts in risk management are urging that customers consider using futures, options, and instruments that promise upside protection without giving up downside participation should another spike occur in the next 9 months," OPIS writes in an Aug. 22 report about wholesale diesel prices.