The average price for a gallon of diesel nationally plunged 7.4 cents to $2.463 for the week ending January 14, according to the Energy Information Administration.
All regions experienced a decline, with the smallest coming in New England, down 5 cents to $2.622. The biggest drop came in the Lower Atlantic - 9 cents to $2.368, making it also the cheapest region.
The most expensive region remained California at $2.773, despite an 8.3-cent decline.