The average pump price of diesel fuel fell 1.6 cents to $3.309 a gallon, the Department of Energy said Monday.
The decline followed last week’s 9.1-cent drop, the biggest of the year.
Trucking’s main fuel hit an all-time high of $3.444 three weeks ago before receding for the past three weekly surveys.
Regular gasoline, meanwhile, dipped 0.2 cent from last week’s $3 level to $2.998 a gallon, DOE said. Gasoline has declined 9.9 cents in the past three weeks.
Diesel prices fell in all five U.S. regions, said, led by a 7.8-cent drop in the Rocky Mountain region to $3.319 a gallon.
The Midwest saw the smallest downturn, falling half a cent to $3.271 a gallon, DOE said.
Each week, DOE surveys about 350 diesel filling stations to compile a national snapshot average price.